ST TDA7540N User Manual

AM/FM car radio tuner IC with stereo decoder and

Features

FM-part

■ RF AGC generation by RF and IF detection

■ I/Q mixer for 1st FM IF 10.7MHz with image

rejection

■ Mixer for 2nd IF 450kHz

■ Internal 450KHz bandpass filter with bandwidth

control by ISS

■ Fully integrated FM-demodulator with spike

cancellation

AM-part

■ Wide and narrow AGC generation

■ Mixer for 1st IF 10.7MHz, AM upconversion

■ Mixer for 2nd IF 450kHz, AM downconversion

■ Integrated AM-demodulator

■ AM IF- and audio noise blanking

Stereodecoder

■ PLL with adjustment free, fully integrated VCO

■ Automatic pilot dependent mono/stereo

switching

■ Programmable ROLL-OFF compensation

■ High cut and stereo blend-characteristics

programmable

■ Dedicated RDS-mute

■ Internal noise blanker with several threshold

controls

Table 1. Device summary

TDA7540N

intelligent selectivity system (ISS)

LQFP80

Additional features

■ VCO for world tuning range

■ High performance fast PLL for RDS-System

■ IF counter for FM and AM with search stop

signal

■ Quality detector for level, deviation, adjacent

channel and multipath

■ ISS (intelligent selectivity system) for

cancellation of adjacent channel and noise
influences

■ Adjacent channel mute

■ Fully electronic alignment

■ All functions I

Description

The TDA7540N is a high performance tuner
circuit for AM/FM car radio. It contains mixer, IF
amplifier, demodulator for AM and FM,
stereodecoder, quality detection, ISS filter and
PLL synthesizer with IF counter on a single chip.
Use of BICMOS technology allows the
implementation of several tuning functions and a
minimum of external components.

2

C-Bus controlled

Order code Temp range, °CPackage Packing

TDA7540N -40 to 85°C LQFP80 (14x14x1.4mm) Tube

TDA7540NTR -40 to 85°C LQFP80 (14x14x1.4mm) Tape and reel

November 2007 Rev 1 1/76

www.st.com

1

Contents TDA7540N

Contents

1 Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

2 Pins description and connection diagrams . . . . . . . . . . . . . . . . . . . . . . 8

2.1 LQFP80 pins connection diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

2.2 Pin description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

3 Electrical specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

3.1 Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

3.2 Thermal data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

3.3 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

3.3.1 Globals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

3.3.2 FM section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

3.3.3 AM section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

3.3.4 Stereodecoder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

3.3.5 PLL Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

4 Functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

4.1 FM section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

4.1.1 Mixer1, AGC and 1.IF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

4.1.2 Mixer2, limiter and demodulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

4.1.3 Quality detection and ISS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

4.1.4 Soft mute control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

4.2 AM section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

4.3 Stereodecoder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

4.3.1 Decoder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

4.3.2 Functional description of the noise blanker . . . . . . . . . . . . . . . . . . . . . . 32

4.3.3 Functional description of the multipath-detector . . . . . . . . . . . . . . . . . . 33

4.3.4 Quality detector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

4.3.5 AFS control and stereo decoder mute . . . . . . . . . . . . . . . . . . . . . . . . . . 34

4.4 PLL and IF counter section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

4.4.1 PLL frequency synthesizer block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

4.4.2 IF counter block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

4.5 I2C-Bus interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

2/76

TDA7540N Contents

5 Software specification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

5.1 Address organization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

5.2 Control register function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

5.2.1 Data byte specification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

6 Appendix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

7 Part list . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

8 Application circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72

9 Application notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73

10 Package information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74

11 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75

3/76

List of tables TDA7540N

List of tables

Table 1. Device summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Table 2. Pin description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Table 3. Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Table 4. Thermal data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Table 5. Globals electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Table 6. FM section electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Table 7. AM section electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Table 8. Stereodecoder electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Table 9. PLL electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Table 10. Address organization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

Table 11. Control register function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Table 12. Subaddress. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

Table 13. Addr 0 Charge Pump Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

Table 14. Addr 1 PLL counter 1 (LSB) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

Table 15. Addr 2 PLL counter 2 (MSB). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

Table 16. Addr 3,4 TV1,2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

Table 17. Addr 5 IF counter control 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

Table 18. Addr 6 IF counter control 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

Table 19. Addr 7 AM control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

Table 20. Addr 8 quality ISS filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

Table 21. Addr 9 quality detection adjacent channel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

Table 22. Addr 10 quality detection multipath. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

Table 23. Addr 11 quality deviation detection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

Table 24. Addr 12 softmute control 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

Table 25. Addr 13 softmute control 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

Table 26. Addr 14 VCODIV/PLLREF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

Table 27. Addr 15 FM AGC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

Table 28. Addr 16 AM AGC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

Table 29. Addr 17 FM demodulator fine adjust. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

Table 30. Addr 18 S-meter slider . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

Table 31. Addr 19 IF GAIN/XTAL adjust. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

Table 32. Tank adjust . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

Table 33. Addr 21 I/Q FM mixer1 adjust . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

Table 34. Addr 22 AM IF noise blanker . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

Table 35. Addr 23 switch control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

Table 36. Addr 24 stereodecoder 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

Table 37. Addr 25 stereodecoder 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

Table 38. Addr 26 stereodecoder 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

Table 39. Addr 27 stereodecoder 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

Table 40. Addr 28 stereodecoder 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

Table 41. Addr 29 stereodecoder 6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

Table 42. Addr 30 stereodecoder 7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

Table 43. Addr 31 stereodecoder 8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

Table 44. Addr 32 stereodecoder 9 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

Table 45. Addr 33 test tuner control 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

Table 46. Addr 34 test tuner control 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

Table 47. Addr 35 test tuner control 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

Table 48. Addr 36 test tuner control 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

4/76

TDA7540N List of tables

Table 49. Addr 37 test tuner control 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

Table 50. Addr 38 test stereodecoder control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

Table 51. Addr39 test FM demodulator spike blanker and stereo decoder . . . . . . . . . . . . . . . . . . . . 63

Table 52. Block diagram quality detection principle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

Table 53. Functional mode quality detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

Table 54. Part list (application- and measurment circuit) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

Table 55. Document revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75

5/76

List of figures TDA7540N

List of figures

Figure 1. Block circuit diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Figure 2. LQFP80 pins connection (top view) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Figure 3. Trigger threshold vs. V
Figure 4. Deviation controlled trigger adjustment
Figure 5. Field strength controlled trigger adjustment

Figure 6. Relation between internal and external level-voltagees and setup of stereoblend. . . . . . . 31

Figure 7. Highcut characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Figure 8. Block diagram I/Q mixer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

Figure 9. Block diagram VCO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

Figure 10. Block diagram keying AGC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

Figure 11. Block diagram ISS function. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

Figure 12. Block diagram AM part . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

Figure 13. Block diagram AM IF noise blanker . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

Figure 14. Block diagram stereodecoder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

Figure 15. Block diagram audio noise blanker. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

Figure 16. Block diagram multipath detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

Figure 17. Block diagram AFS function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70

Figure 18. Application circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72

Figure 19. LQFP80 (14x14x1.40mm) mechanical data and package dimensions. . . . . . . . . . . . . . . . 74

PEAK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

6/76

TDA7540N Block diagram

1 Block diagram

Figure 1. Block circuit diagram

7/76

Pins description and connection diagrams TDA7540N

2 Pins description and connection diagrams

2.1 LQFP80 pins connection diagram

Figure 2. LQFP80 pins connection (top view)

IF1AMP1IN

IF1REF

IF1AMP1OUT

VCCIF1

IF1AMP2IN

AMDETC

IF1AMP2OUT

AMRFAGCTC

FMM1X2REF

FMM1X2IN

VCC2

AMMIX2OUT1

AMMIX2OUT2

GNDVCC2

60

59

58

57

56

55

54

53

52

51

50

49

48

47

46

45

44

43

42

41

VREF1

AMIF2IN

MPXW

GNDDEM

FMREFDEMC

AMIF2REF

AMIF2BPF

MPXOUT

AFS

VCCSTEREO

MPXIN

MUTETC

MPTC

GNDSTEREO

QUALYOUT

FSWO

VCC1

L

R

GNDVCC1

MIX1 OUT1

TEST1

DEVTC

AMMIX1IN

AMMIX1REF

AMRFAGCOUT

AMPINDR

FMPINDR

FMMIX1IN1

GNDRF

FMMIX1IN2

TV1

TV2

ISSSTATUS

FMAGCTC

VCOB

VCOE

VCCVCO

S1

S2

TEST2

MIX1OUT2

79

80

1

2

3

4

5

6

7

8

9

10

12

13

14

15

16

17

18

19

20

21 22 23 24 25

GNDIF1

IF1AGCIN

AMAGC2TC

75 74 73 727071 69 68 67 66 65

76

77

78

26 27 28 29 30

AMREFDEMC

311132 33 34 35 36

64 63 62 61

37 38 39 40

2.2 Pin description

Table 2. Pin description

Pin # Pin name Function

1 MIX1OUT1 Mixer tank 10.7MHz

2 TEST1 Testing I/O pin

3 DEVTC Deviation detector time constant

4 AMMIX1IN AM mixer1 input

5 AMMIX1REF AM mixer1 reference

6 AMRFAGCOUT Output AM RF AGC

7 AMPINDR AM pin diode driver output

8 FMPINDR FM pin diode driver output

9 FMMIX1IN1 FM mixer1 input1

FSU

GNDVCO

ADJCH

AMST/MP

XTALG

STEREO

ISSTC1

ISSTC2

XTALD

SDA

SSTOP

SCL

FSTC

LPOUT

GNDVCC3

VCC3

VREF2

LPAM

LPFM

LPHC

D06AU1653

8/76

TDA7540N Pins description and connection diagrams

Table 2. Pin description (continued)

Pin # Pin name Function

10 GNDRF RF ground

11 FMMIX1IN2 FM mixer1 input2

12 TV1 Tuning voltage preselection1

13 TV2 Tuning voltage preselection2

14 ISSSTATUS ISS filter status output

15 S1 Free programmable switching output

16 FMAGCTC FM AGC time constant

17 S2 Free programmable switching output

18 VCOB VCO input base

19 VCOE VCO output emitter

20 VCCVCO VCO supply

21 GNDVCO VCO ground

22 FSU Unweighted fieldstrength output

23 ADJCH Ident. adjacent channel output

24 AMST/MP AM stereo output / ident. multipath output

25 STEREO Stereo information indication output

26 XTALG Xtal oscillator to MOS gate

27 ISSTC1 Time constant1 ISS filter switch

28 ISSTC2 Time constant2 ISS filter switch

29 XTALD Xtal oscillator to MOS drain

30 SSTOP Search stop output

31 SDA I

32 SCL I

33 FSTC S-meter filtering capacitor

34 GNDVCC3 VCC3 ground

35 LPOUT Op amp output to PLL loop filters

36 VCC3 Supply tuning voltage

37 VREF2 Voltage reference for PLL op amp

38 LPAM Op amp input to PLL loop filters AM

39 LPFM Op amp input to PLL loop filters FM

40 LPHC High current PLL loop filter input

41 GNDVCC1 Digital ground

42 R Stereodecoder output right

43 L Stereodecoder output left

44 VCC1 Digital supply

45 FSWO Weighted fieldstrength output with programmable DC offset

46 Qualyout Stereodecoder quality output

2

C-Bus data

2

C-Bus clock

9/76

Pins description and connection diagrams TDA7540N

Table 2. Pin description (continued)

Pin # Pin name Function

47 GNDSTEREO Strereodecoder ground

48 MPTC Multipath time constant

49 MUTETC Weak signal mute time constant

50 MPXIN Stereodecoder Input

51 VCCSTEREO Stereodecoder supply

52 AFS Alternative frequency search drive

53 MPX/AFAM MPX output / AM AF output

54 AMIF2BPF AM IF2 bandpass filter

55 AMIF2REF Reference voltage AM IF2 amplifier

56 FMREFDEMC FM demodulator reference

57 GNDDEM Ground FM demodulator

58 MPXW MPX Output without ISS filtering

59 AMIF2IN Input AM IF2

60 VREF1 Reference 5V

61 GNDVCC2 Analog ground

62 AMMIX2OUT2 AM Tank 450kHz

63 AMMIX2OUT1 AM Tank 450kHz

64 VCC2 Analog supply

65 FMMIX2IN FM IF1 mixer2 input

66 FMMIX2REF FM IF1 mixer2 reference

67 AMRFAGCTC AM RF AGC time constant

68 IF1AMP2OUT IF1 amplifier2 output

69 AMDETC AM detector capacitor

70 AMREFDEMC AM demodulator reference

71 IF1AMP2IN IF1 amplifier2 input

72 VCCIF1 IF1 supply

73 IF1AMP1OUT IF1 amplifier1 output

74 IF1REF IF1 amplifier reference

75 IF1AMP1IN IF1 amplifier1 input

76 GNDIF1 IF1 ground

77 IF1AGCIN IF1 AGC input

78 AMAGC2TC AM AGC2 time constant

79 TEST2 Testing I/O pin

80 MIX1OUT2 Mixer tank 10.7MHz

10/76

TDA7540N Electrical specifications

3 Electrical specifications

3.1 Absolute maximum ratings

Table 3. Absolute maximum ratings

Symbol Parameter Value Units

T

V

amb

T

Supply voltage 9.5 V

S

Ambient temperature -40 to 85 °C

Storage temperature -55 to 150 °C

stg

3.2 Thermal data

Table 4. Thermal data

Symbol Parameter Value Unit

Thermal resistance junction to ambient Max. 55 °C/W

R

th(j-amb)

3.3 Electrical characteristics

3.3.1 Globals

Table 5. Globals electrical characteristics

Symbol Parameter Test conditions Min. Typ. Max. Unit

(T

= 25°C, V

amb

f

= 10.25MHz, in application circuit, unless otherwise specified).

Xtal

CC1

= V

CC2

= V

CC3

= V

CCST

= V

CCVCO

= V

CCMIX1

= V

CCMIX2

= V

CCIF1

=8.5V,

Supply

V

CC1

V

CC2

V

CC3

V

CCVCO

V

CCMIX1

V

CCMIX2

V

CCIF1

V

CCST

I

CC1

I

CC1

I

CC2

I

CC2

Digital supply voltage 7.7 8.5 9 V

Analog supply voltage 7.7 8.5 9 V

Analog tuning voltage 7.7 8.5 9 V

VCO supply voltage 7.7 8.5 9 V

MIX1 supply voltage 7.7 8.5 9 V

MIX2 supply voltage 7.7 8.5 9 V

IF1 supply voltage 7.7 8.5 9 V

Stereo supply voltage 7.7 8.5 9 V

Supply current FM ON 10 12 mA

Supply current AM ON 10 12 mA

Supply current FM ON / VCO:3 65 78 mA

Supply current AM ON 75 90 mA

11/76

Electrical specifications TDA7540N

Table 5. Globals electrical characteristics (continued)

(T

= 25°C, V

amb

f

= 10.25MHz, in application circuit, unless otherwise specified).

Xtal

Symbol Parameter Test conditions Min. Typ. Max. Unit

CC1

= V

CC2

= V

CC3

= V

CCST

= V

CCVCO

= V

CCMIX1

= V

CCMIX2

= V

CCIF1

=8.5V,

I

CC3

I

CCVCO

I

CCMIX1

I

CCMIX1

I

CCMIX2

I

CCIF1

I

CCST

Supply current 2 3 mA

Supply current 8 10 mA

Supply current FM ON 8 10 mA

Supply current AM ON 7 8.5 mA

Supply current AM ON 7 8.5 mA

Supply current 5 6.5 mA

Supply current 12 13.5 mA

Reference voltages

V

REF1

V

REF2

2

C-Bus interface

I

f

SCL

V

V

I

IN

V

Internal reference voltage I

Internal reference voltage I

Clock frequency 400 kHz

Input low voltage 1 V

IL

Input high voltage 3 5 V

IH

Input current -5 5 μA

Output acknowledge voltage IO = 1.6mA 0.4 V

O

= 0mA 4.8 5 5.2 V

REF1

= 0mA 2.4 2.5 2.6 V

REF2

3.3.2 FM section

Table 6. FM section electrical characteristics

Symbol Parameter Test conditions Min. Typ. Max. Unit

Wide band RF AGC

V

9-11

V

9-11

Narrow band IF & keying AGC

V

V

V

(T

amb

f

= 98MHz, dev= 40kHz, f

RF

otherwise specified).

Lower threshold start V16 = 2.5V 83 85 87 dBμV

Upper threshold start V16 = 2.5V 94 96 98 dBμV

77

77

77

Lower threshold start KAGC = off, V

Upper threshold start KAGC = off, V

Lower threshold start with
KAGC

= 25°C, V

CC1

= V

= V

CC2

MOD

KAGC = max,
V

ΔfIF=300KHz

= V

CC3

= 1kHz, f

= 0mV

9-11

= V

CCST

RMS,

CCVCO

= 10.25MHz, in application circuit, unless

Xtal

= 0mV

9-11

= 0mV

9-11

RMS

RMS

= V

CCMIX1

= V

CCMIX2

84 86 88 dBμV

96 98 100 dBμV

96 98 100 dBμV

= V

CCIF1

= 8.5V,

12/76

TDA7540N Electrical specifications

Table 6. FM section electrical characteristics (continued)

(T

= 25°C, V

amb

f

= 98MHz, dev= 40kHz, f

RF

CC1

= V

CC2

= V

MOD

= V

CC3

= 1kHz, f

= V

CCST

CCVCO

= 10.25MHz, in application circuit, unless

Xtal

= V

CCMIX1

= V

CCMIX2

= V

CCIF1

= 8.5V,

otherwise specified).

Symbol Parameter Test conditions Min. Typ. Max. Unit

KAGC = max,
V

= 0mV

V

22

Startpoint KAGC

Δ Control range KAGC ΔV

R

IN

C

IN

Input resistance 10 13 16 kΩ

Input capacitance 2.5 pF

AGC time constant output

V

16

V

16

I

16

I

16

Max. AGC output voltage V

Min. AGC output voltage V

Min. AGC charge current V

Max. AGC discharge current V

AGC pin diode driver output

9-11

ΔfIF=300KHz
f

generates FS level at V

IF1

= +0.8V 16 dB

22

9-11

9-11

9-11

9-11

= 0mV

= 50mV

= 0mV

= 50mV

RMS,

RMS

RMS

RMS,V16

RMS,V16

2.2 V

22

V

REF1

+V

BE

V

0.5 V

= 2.5V -16.5 -12.5 -8.5 μA

= 2.5V 0.8 1.25 1.68 mA

I

8

I

8

AGC OUT, current min. V

AGC OUT, current max. V

9-11

9-11

= 0mV

= 50 mV

, V8 = 2.5V 12 μA

RMS

, V8 = 2.5V -22 -17 -12 mA

RMS

I/Q Mixer1 (10.7MHz)

R

V

R

C

OUT

9,11

g

IN

IN

m

Input resistance differential 10 kΩ

Input capacitance differential 4 pF

Output resistance differential 100 kΩ

Input DC bias 2.2 2.5 2.8 V

Conversion
transconductance

17 ms

F Noise figure 400Ω generator resistance 3 dB

CP

1dB

1dB compression point referred to diff. mixer input 100 dBμV

IIP3 3rd order intermodulation 122 dBμV

IQP I/Q phase adjust PH -7 +8 °

IRR Image rejection ratio ratio wanted/image 30 40 dB

IRR Image rejection ratio with phase adjust 40 46 dB

IF1 Amplifier1 +2 (10.7MHz)

G2 Gain 5 6 7 dB

G1

G1

min

max

Min. gain IFG1 7.5 9 10.5 dB

Max. gain IFG1 16 18 20 dB

13/76

Electrical specifications TDA7540N

Table 6. FM section electrical characteristics (continued)

(T

= 25°C, V

amb

f

= 98MHz, dev= 40kHz, f

RF

CC1

= V

CC2

= V

MOD

= V

CC3

= 1kHz, f

= V

CCST

CCVCO

= 10.25MHz, in application circuit, unless

Xtal

= V

CCMIX1

= V

CCMIX2

= V

CCIF1

= 8.5V,

otherwise specified).

Symbol Parameter Test conditions Min. Typ. Max. Unit

R

IN

R

OUT

CP

1dB

IIP3 3rd order Intermodulation ref. to 330Ω

Input resistance 260 330 400 W

Output resistance 260 330 400 W

1dB compression point referred to 330Ω input 105 dBμV

input, 9dB gain 126 dBμV

Mixer2 (450kHz)

R

IN

V

65

V

65

Input impedance 260 330 400 Ω

Max. input voltage 119 dBμV

Limiting sensitivity S/N = 20dB 28 dBμV

G Mixer gain 18 dB

Limiter 1 (450kHz)

G

Limiter

Gain 80 dB

Demodulator, audio output

THD

V

R

|ΔV|

|ΔV|

S/N

V

MPXW

MPX

OUT

min

max

MPX output signal Dev.= 75kHz 400 500 600 mV

Output impedance 50 Ω

DC offset fine adjust DEM, MENA=1 8.5 mV

DC offset fine adjust DEM, MENA=1 264 mV

MPXW output signal Dev.= 75kHz 280 350 420 mV

Dev.= 75kHz, V65= 10mV

Dev.= 40kHz,V65 = 10mV

RMS

RMS

76 dB

Quality detection

0.1 %

RMS

RMS

S-meter, unweighted fieldstrength

ΔV

ΔV

ΔV

R

V

V

V

OUT

T

65

22

22

K

Min. input voltage MIX2 30 dBμV

Fieldstrength output V65 = 20dBµV 0.1 V

Fieldstrength output V65 = 80dBµV, SMSL = 0 2.2 2.6 3.0 V

Voltage per decade SMSL = 0 0.8 1 1.2 V

22

Voltage per decade SMSL = 1 1.2 1.5 1.8 V

22

S-meter offset SL, SMSL=1 -15 15 dB

22

Output impedance 280 400 520 Ω

Coefficient temperature 0 ppm/K

14/76

TDA7540N Electrical specifications

Table 6. FM section electrical characteristics (continued)

(T

= 25°C, V

amb

f

= 98MHz, dev= 40kHz, f

RF

CC1

= V

CC2

= V

MOD

= V

CC3

= 1kHz, f

= V

CCST

CCVCO

= 10.25MHz, in application circuit, unless

Xtal

= V

CCMIX1

= V

CCMIX2

= V

CCIF1

= 8.5V,

otherwise specified).

Symbol Parameter Test conditions Min. Typ. Max. Unit

Adjacent channel gain

G

min

G

max

Gain minimum ACG=0 32 dB

Gain maximum ACG=1 38 dB

Adjacent channel filter

f

HP

f

BP

f

-20dB

-3dB frequency highpass ACF=0 100 kHz

Centre frequency ACF=1 100 kHz

Attenuation 20dB 70 kHz

Adjacent channel output

R

V

V

OUT

23

23

Output voltage low 0.1 V

Output voltage high 4.9 V

Output resistance 3.5 4.5 5.5 kΩ

Multipath channel gain

G

min

G

max

Gain minimum MPG=0 12 dB

Gain maximum MPG=1 23 dB

Multipath bandpass filter

f

BP19

f

BP31

Centre frequency MPF=0 19 kHz

Centre frequency MPF=1 31 kHz

Q Quality factor 5 8 10

Multipath output

Output voltage low 0.1 V

Output voltage high 4.9 V

Output resistance 3 kΩ

R

V

V

OUT

24

24

ISS (intelligent Selectivity System)

Filter 450kHz

f

centre

Centre frequency f

REF_intern

= 450kHz 450 kHz

BW 3dB Bandwidth, -3dB ISS80 = 1 70 80 90 kHz

BW 20dB Bandwidth, -20dB ISS80 = 1 132 150 168 kHz

BW 3dB Bandwidth, -3dB ISS80 = 0 106 120 135 kHz

BW 20dB Bandwidth, -20dB ISS80 = 0 220 250 280 kHz

BW 3dB Bandwidth weather band ISS30 = 1 20 30 40 kHz

BW 20dB -20dB weather band ISS30 = 1 56 80 104 kHz

15/76

Electrical specifications TDA7540N

Table 6. FM section electrical characteristics (continued)

(T

= 25°C, V

amb

f

= 98MHz, dev= 40kHz, f

RF

CC1

= V

CC2

= V

MOD

= V

CC3

= 1kHz, f

= V

CCST

CCVCO

= 10.25MHz, in application circuit, unless

Xtal

= V

CCMIX1

= V

CCMIX2

= V

CCIF1

= 8.5V,

otherwise specified).

Symbol Parameter Test conditions Min. Typ. Max. Unit

Adjacent channel ISS filter threshold

V

NTH

V

NTH

V

WTH

V

WTH

V

THMP

V

THMP

I

27,I28

I

27,I28

I

27,I28

I

27,I28

I

27,I28

I

27,I28

V

27,V28

V

27,V28

Internal low threshold ACNTH 0 V

Internal high threshold ACNTH 0.24 0.3 0.36 V

Internal low threshold ACWTH 0.2 0.25 0.3 V

Internal high threshold ACWTH 0.76 0.95 1.14 V

Multipath threshold

Internal low threshold MPTH 0.40 0.50 0.60 V

Internal high threshold MPTH 1.0 1.25 1.5 V

ISS filter time constant

Charge current low mid TISS, ISSCTL = 1 -96 -74 -54 μA

Charge current high mid TISS, ISSCTL = 1 -60 μA

Charge current low narrow TISS, ISSCTL = 1 -165 -124 -87 μA

Charge current high narrow

TISS, ISSCTL = 1 -110 μA

Discharge current low TISS, ISSCTL = 0 -0.4 1 2.0 μA

Discharge current high TISS, ISSCTL = 0 10 15 20 μA

Low voltage ISSCTL = 0 0.1 0.2 V

High voltage ISSCTL = 1 4.6 4.9 V

ISS filter switch threshold

V

27,V28

V

27,V28

V

27,V28

V

27,V28

I

I

I

I

DEV

DEV

RATIO

RATIO

3

3

3

3

Threshold ISS on ISSCTL = 0 3 V

Threshold ISS off ISSCTL = 0 1 V

Threshold ISS narrow on ISSCTL = 0 4 V

Threshold ISS narrow off ISSCTL = 0 2 V

Charge current low TDEV -20 -32 -40 μA

Charge current high TDEV -30 -39 -48 μA

Discharge current low TDEV 0.5 1 1.5 μA

Discharge current high TDEV 5.5 8 10.5 μA

Internal low threshold DWTH 30 kHz

WTH

Internal high threshold DWTH 75 kHz

WTH

Referred to threshold DTH 1

min

Referred to threshold DTH 1.5

max

16/76

TDA7540N Electrical specifications

Table 6. FM section electrical characteristics (continued)

(T

= 25°C, V

amb

f

= 98MHz, dev= 40kHz, f

RF

CC1

= V

CC2

= V

MOD

= V

CC3

= 1kHz, f

= V

CCST

CCVCO

= 10.25MHz, in application circuit, unless

Xtal

= V

CCMIX1

= V

CCMIX2

= V

CCIF1

= 8.5V,

otherwise specified).

Symbol Parameter Test conditions Min. Typ. Max. Unit

Softmute

V

ANT

V

ANT

a

SMmin

a

SMmax

a

SMTHISS

V

ACTH

a

SMAC

I

49

I

49

Upper startpoint SMTH, SMD, SLOPE = 0 10 dBμV

lower startpoint SMTH, SMD, SLOPE = 0 3 dBμV

Min. softmute depth

Max. softmute depth

Mute depth threshold for ISS
filter on

SMD, SLOPE = 0, SMTH

SMD, SLOPE = 0, SMTH

SMCTH 0.2 1 2 dB

Internal AC mute threshold ACM 60 340 mV

AC mute depth ACMD 4 10 dB

Charge current -65 -47.5 -30 μA

Discharge current 1.5 2.5 4.0 μA

S/N MPX

V

= 60dBμV,

ANT

(S+N)/N

dev.= 40kHz,LP=15KHz
deemphasis t = 50

3.3.3 AM section

Table 7. AM section electrical characteristics

(T

= 25°C, V

amb

f

= 98MHz, m= 30%, f

RF

CC1

otherwise specified).

= V

CC2

MOD

= V

= V

CC3

= 400kHz, f

Upper

Upper

18 dB

36 dB

66 69 dB

μs

= V

CCST

CCVCO

= 10.25MHz, in application circuit, unless

Xtal

= V

CCMIX1

= V

CCMIX2

= V

CCIF1

= 8.5V,

Symbol Parameter Test conditions Min. Typ. Max. Unit

Global

V

(S+N)/N Signal to Noise Ratio Ref.: V

Usable sensitivity (S+N)/N = 26 dB 25 19 dBµV

ANT_us

ΔV

ANT

a

IF

f

AF

THD Total Harmonic Distortion

V

53

IF2 AGC Range Ref.: V

IF rejection

Frequency response

Ref: V
IF = 10.7MHz

Ref.: V

ΔV

= -3 dB

AF

V

INRF

m = 0.3
V

INRF

m = 0.3

AF output level V

INRF

= 60dBμV, 50 52 dB

INRF

= 60dBμV5055 dB

INRF

= 60dBµV,

INRF

= 60dBµV,

INRF

= 60dBµV, m = 0.8

70 80 dB

3.6 kHz

0.5

0.3

= 120dBµV, m = 0.8

1.0

0.3

= 60dBµV 160 180 200 mV

17/76

%

RMS

Electrical specifications TDA7540N

Table 7. AM section electrical characteristics (continued)

(T

= 25°C, V

amb

f

= 98MHz, m= 30%, f

RF

CC1

= V

CC2

MOD

= V

= V

CC3

CCST

= 400kHz, f

= V

CCVCO

= 10.25MHz, in application circuit, unless

Xtal

= V

CCMIX1

= V

CCMIX2

= V

CCIF1

= 8.5V,

otherwise specified).

Symbol Parameter Test conditions Min. Typ. Max. Unit

V

V

V

|I

78max

24

V

71

71

IF output level V

Min. RF AGC threshold

4

Max. RF AGC threshold

Min. IF AGC threshold
Max. IF AGC threshold

Min. DAGC threshold
Max. DAGC threshold

= 60dBµV, m=off 190 mV

INRF

WAGC

WAGC

DAGC

97

109

96.5
109

74
96

| AGC2 charge current seek 80 100 120 μA

CCR Charge current ratio seek/seek off 30

AGC voltage driver output

V

V

| I

6

Max. AGC output voltage 3.5 V

6

Min. AGC output voltage 0.5 V

6

| AGC current 100 μA

AGC pin diode driver output

I

7

AGC driver current -2.6 -2 -1.4 mA

AM Mixer1 (10.7MHz)

R

CP

R

C

OUT

IN

IN

1dB

Input resistance differential 100 kΩ

Input capacitance differential 4 pF

Output impedance differential 100 kΩ

1dB compression point referred to diff. mixer input 112 dBμV

IIP3 3rd order intermodulation 132 dB

F Noise figure 8 dB

AGain 26 dB

RMS

dBμV
dBμV

dBμV
dBμV

dBμV
dBμV

μV

C

min

C

max

C

1-80

Min. capacitance step IF1T 0.55 pF

Max. capacitance IF1T 8.25 pF

IF1T 2 pF

AM Mixer2 (450kHz)

CP

R

71

C

71

1dB

Input resistance 260 330 400 W

Input capacitance 2.5 pF

1dB compression point referred to diff. mixer input 120 dBμV

IIP3 3rd order intermodulation 132 dBμV

F Noise figure 12 dB

18/76

TDA7540N Electrical specifications

Table 7. AM section electrical characteristics (continued)

(T

= 25°C, V

amb

f

= 98MHz, m= 30%, f

RF

CC1

= V

CC2

MOD

= V

= V

CC3

CCST

= 400kHz, f

= V

CCVCO

= 10.25MHz, in application circuit, unless

Xtal

= V

CCMIX1

= V

CCMIX2

= V

CCIF1

= 8.5V,

otherwise specified).

Symbol Parameter Test conditions Min. Typ. Max. Unit

A Max. gain Mixer2 tank output 34 dB

ΔA Gain control range 20 dB

C

min

C

max

C

62-63

IF noise blanking

Min. cap step IF2T 1.6 pF

Max. cap IF2T 24 pF

IF2T 2 pF

V

V

V

thstep

V

V

t

bl

t

bl

th

th

desth

desth

Min. blanking time 8 μs

Max. blanking time 17 μs

Min internal threshold 10 12.5 15 mV

Max. internal threshold 150 187.5 225 mV

Threshold step 10 12.5 15 mV

Min. desensitivity threshold 2.9 3.2 3.5 V

Max. desensitivity threshold 3.6 4 4.4 V

3.3.4 Stereodecoder

Table 8. Stereodecoder electrical characteristics

Symbol Parameter Test conditions Min. Typ. Max. Unit

Stereodecoder

V

R

G

min

G

max

G

step

SVRR Supply voltage ripple rejection V

a Max. channel separation

(T
V

amb

MPX

= 25°C, V
= 500mV

= V

CC1

mono, f = 1kHz, deemphasis = 50µs, f

rms

circuit, unless otherwise specified).

in

in

MPX input level STD Gain = 2.5 dB 0.5 0.93 V

Input resistance 70 100 130 kΩ

Min. Stereodecoder gain -0.5 0 0.5 dB

Max. Stereodecoder gain 3.15 3.75 4.35 dB

Stereodecoder gain step
resolution

CC2

= V

V
only L/R

CC3

= V

CCST

= V

CCVCO

= V

= V

CCMIX1

= 10.25MHz, in application

Xtal

CCMIX2

= V

1 1.25 1.5 dB

= 100mV, f = 1kHz 54 60 dB

ripple

= 500mV

MPX

rms

stereo

50 dB

CCIF1

= 8.5V,

rms

THD Total harmonic distortion 0.02 0.3 %

(S+N)/N

Signal plus Noise to Noise
ratio

A-weighted, 19kHz notch 85 dB

19/76

Electrical specifications TDA7540N

Table 8. Stereodecoder electrical characteristics (continued)

(T
V

amb

MPX

= 25°C, V
= 500mV

= V

CC1

mono, f = 1kHz, deemphasis = 50µs, f

rms

CC2

= V

CC3

= V

CCST

= V

CCVCO

= V

= V

CCMIX1

= 10.25MHz, in application

Xtal

CCMIX2

= V

CCIF1

= 8.5V,

circuit, unless otherwise specified).

Symbol Parameter Test conditions Min. Typ. Max. Unit

V

R

V

V

puafs

puafs

TH1

TH2

Pull up voltage for AFS pin 3.1 3.3 3.5 V

Pull up resistor for AFS pin 25 kΩ

1. threshold for AFS PIN 2.2 2.4 2.6 V

2. threshold for AFS PIN 0.6 0.8 1.0 V

Mono/stereo-switch

V

PTHST1

V

PTHST0

V

PTHMO1

V

PTHMO0

Pilot threshold voltage for Mono->Stereo, PTH = 1 6 10 15 mV

Pilot threshold voltage for Mono->Stereo, PTH = 0 10 14 19 mV

Pilot threshold voltage for Stereo->Mono, PTH = 1 4 8 12 mV

Pilot threshold voltage for Stereo->Mono, PTH = 0 7 12 16 mV

19kHz PLL

f

lock

PLL lock range

Pilot magnitude
20 mV

rms

= 4%

18.9 19.1 kHz

DP Pilot deviation Pilot frequency 19kHz 4 30 %

Deemphasis- and highcut

t

HC50

t

HC75

t

HC25

t

HC37

t

HC50

t

HC75

F

AMCMin

F

AMCMin

Deemphasis time constant

Deemphasis time constant

Deemphasis time constant

Deemphasis time constant

Highcut time constant

Highcut time constant

Min. AM corner frequency

Max. AM corner frequency

DEEMP = 0, DESFT = 1

>> V

V

LEVEL

HCH

DEEMP = 1, DESFT = 1

>> V

V

LEVEL

HCH

DEEMP = 0, DESFT = 0

>> V

V

LEVEL

HCH

DEEMP = 1, DESFT = 0

>> V

V

LEVEL

HCH

DEEMP = 0, DESFT = 1

<< V

V

LEVEL

HCL

DEEMP= 1, DESFT = 1

<< V

V

LEVEL

HCL

DEEMP = 0, DESFT = 1
AMCF

DEEMP = 0, DESFT = 1
AMCF

50 μs

75 μs

25 μs

37.5 μs

150 μs

225 μs

1.06 kHz

3.18 kHz

rms

rms

rms

rms

Stereoblend- and highcut-control

L

L

Gmax

L

Gstep

Gmin

Min. level gain LG -0.5 0 0.5 dB

Max. level gain LG 4.0 4.7 5.2 dB

Level gain step resolution LG 0.4 0.67 0.9 dB

20/76

TDA7540N Electrical specifications

Table 8. Stereodecoder electrical characteristics (continued)

(T
V

amb

MPX

= 25°C, V
= 500mV

= V

CC1

mono, f = 1kHz, deemphasis = 50µs, f

rms

CC2

= V

CC3

= V

CCST

= V

CCVCO

= V

= V

CCMIX1

= 10.25MHz, in application

Xtal

CCMIX2

= V

CCIF1

= 8.5V,

circuit, unless otherwise specified).

Symbol Parameter Test conditions Min. Typ. Max. Unit

VSBL

VSBL

VSBL

VHCH

VHCH

VHCH

VHCL

VHCL

VHCL

Min. voltage for mono SBC 29 33 %V

min

Max. voltage for mono SBC 54 58 %V

max

Step resolution SBC 4.2 %V

step

Min. voltage for no highcut VHCH 42 46 %V

min

Max. Voltage for no highcut VHCH 61 66 %V

max

Step resolution VHCH 8 %V

step

Min. voltage for full high cut VHCL, MAXHC = 11 11 15 %VHCH

min

Max. voltage for full high cut VHCL, MAXHC = 11 31 33 %VHCH

max

Step resolution VHCL, MAXHC = 11 7.3 %VHCH

step

Carrier and harmonic suppression at the output

a19 Pilot signal f=19kHz V

= 50mV

pilot

rms

50 dB

a38 Subcarrier f=38kHz 75 dB

a57 Subcarrier f=57kHz 62 dB

a76 Subcarrier f=76kHz 90 dB

(2)

(1)

=10kHz, f

mod

=13kHz, f

mod

=1kHz 65 dB

spur

=1kHz 75 dB

spur

Intermodulation

a2 f

a3 f

Traffic radio

REF1

REF1

REF1

REF1

REF1

REF1

a57 Signal f=57kHz 70 dB

SCA - Subsidiary communications authorization

(3)

a67 Signal f=67kHz 75 dB

ACI - adjacent channel interference

(4)

a114 Signal f=114kHz 95 dB

a190 Signal f=190kHz 84 dB

FM noise blanker

(5)

(5)

(5)

0)

V

=0.8V, NBLTH 147 mV

PEAK

V

=0.8V, NBLTH 280 mV

PEAK

19 mV

V

=1.5V, NBCTH 450 mV

PEAK

V

=1.5V, NBCTH 1200 mV

PEAK

V

TRMIN

V

TRMAX

V

TRSTEP

V

TRNOISE

V

TRNOISE

Min. trigger threshold

Max. trigger threshold

Trigger threshold step

Min. noise controlled trigger
threshold

(5)

Max. noise controlled
trigger threshold

21/76

OP

OP

OP

OP

OP

Electrical specifications TDA7540N

Table 8. Stereodecoder electrical characteristics (continued)

(T
V

amb

MPX

= 25°C, V
= 500mV

= V

CC1

mono, f = 1kHz, deemphasis = 50µs, f

rms

CC2

= V

CC3

= V

CCST

= V

CCVCO

= V

= V

CCMIX1

= 10.25MHz, in application

Xtal

CCMIX2

= V

CCIF1

= 8.5V,

circuit, unless otherwise specified).

Symbol Parameter Test conditions Min. Typ. Max. Unit

V

PEAK

V

PEAK

V

PEAK

V

PEAKDEV

V

PEAKDEV

V

PEAKFS

V

PEAKFS

T

S

T

S

SR

PEAK

SR

PEAK

V

RECTADJ

Peak voltage NBRR = 00, V

Peak voltage V

Peak voltage V

Min. deviation dependent
peak voltage

Max. deviation dependent
peak voltage

Min. fieldstrength controlled
peak voltage

Max. fieldstrength controlled
peak voltage

Min. blanking time

Max. blanking time

Noise rectifier charge

Noise rectifier charge

Noise rectifier discharge
adjustment

=50mV, f=150kHz 1.6 1.9 2.1 V

MPX

=200mV, f=150kHz 2.2 2.5 2.7 V

MPX

V

=500mV, NBDTH = 11 0.5 0.8 (off) 1.0 V

MPX

V

=500mV, NBDTH= 00 1.7 2.0 2.2 V

MPX

V

=0mV, V

MPX

(fully mono), NBFS = 11

V

=0mV, V

MPX

(fully mono), NBFS = 00

Signal HOLDN in testmode,
NBT

Signal HOLDN in testmode,
NBT

Signal PEAK in testmode,
NBPC=0

Signal PEAK in testmode,
NBPC=1

Signal PEAK in testmode,
NBRR=00, NBSMP=0,
MPPC=0

=0mV 0.5 0.8 1.0 V

MPX

<< V

LEVEL

LEVEL

<< V

SBL

SBL

0.5 0.8 (off) 1.0 V

1.7 2.0 2.2 V

22 μs

38 μs

10 mV/μs

20 mV/μs

0.3 V/ms

OP

OP

Signal PEAK in testmode,
NBRR=01, NBSMP=0,
MPPC=0

Signal PEAK in testmode,
NBRR=10, NBSMP=0,
MPPC=0

Signal PEAK in testmode,
NBRR=11, NBSMP=0,
MPPC=0

Signal PEAK in testmode,

=1V, NBSMP=0,

V

MPTC

MPPC=1, NBRR=01

Signal PEAK in testmode,

=1V,, NBSMP=1,

V

MPTC

MPPC=0, NBRR=01

Signal PEAK in testmode,
V

=1V,, NBSMP=1,

MPTC

MPPC=1A, NBRR=01

V

RECTADJ

V

RECTADJ

V

RECTADJ

V

ADJMP

V

ADJMP

V

ADJMP

Noise rectifier discharge
adjustment

Noise rectifier discharge
adjustment

Noise rectifier discharge
adjustment

Noise rectifier adjustment by
multipath

Noise rectifier adjustment by
strong multipath influence

Noise rectifier adjustment by
multipath and strong multipath
influence

22/76

0.8 V/ms

1.3 V/ms

2.0 V/ms

2.5 V/ms

3.3 V/ms

4.5 V/ms

TDA7540N Electrical specifications

Table 8. Stereodecoder electrical characteristics (continued)

(T
V

amb

MPX

= 25°C, V
= 500mV

= V

CC1

mono, f = 1kHz, deemphasis = 50µs, f

rms

CC2

= V

CC3

= V

CCST

= V

CCVCO

= V

= V

CCMIX1

= 10.25MHz, in application

Xtal

CCMIX2

= V

CCIF1

= 8.5V,

circuit, unless otherwise specified).

Symbol Parameter Test conditions Min. Typ. Max. Unit

G

AMdelay

AM delay filter attenuation f = 2.2kHz 2.0 dB

Multipath detector

f

CMP

G

BPMP

G

BPMP

G

RECTMP

G

RECTMP

I

CHMP

I

CHMP

I

DISMP

Center frequency of multipath­bandpass

Min. band pass gain MPBPG 4 6 8 dB

Max. band pass gain MPBPG 10 12 14 dB

Min. rectifier gain MPRG -1 0 1 dB

Max. rectifier gain MPRG 4.5 7.6 9.5 dB

Rectifier charge current MPCC = 0 0.5 0.8 1.2 μA

Rectifier charge current MPCC = 1 0.2 0.4 0.6 μA

Rectifier discharge current 0.3 0.6 0.8 mA

stereo decoder locked on pilot
tone

19 kHz

Quality detector

a Min. MP influence factor QDC 0.5 0.6 0.7

aMax. MP

influence factor QDC 0.9 1.05 1.2

A Min. noise influence factor QNG 6 dB

A Max. noise influence factor QNG 15 dB

1. Intermodulation Suppression

2 = VO(signal,@1KHz) / VO(spurious, @1KHz) ; fs = (2x10KHz) - 19KHz

a

a

3 = VO(signal,@1KHz) / VO(spurious, @1KHz) ; fs = (3x13KHz) - 38KHz

measured with: 91% stereo signal; 9% pilot signal; fm = 10kHz or 13kHz.

2. Traffic Radio (V.F.) Suppression

57(V,W,F) = VO(signal,@1KHz) / VO(spurious, @1KHz+/-23KHz)

a

measured with: 91% stereo signal; 9% pilot signal; fm=1kHz; 5% sub carrier (f=57kHz, fm=23Hz AM, m=60%)

3. SCA ( Subsidiary Communications Authorization )

67 = VO(signal,@1KHz) / VO(spurious, @9KHz) ; fs = (2x38KHz) - 67KHz

a

measured with: 81% mono signal; 9% pilot signal; fm=1kHz; 10%SCA – sub carrier ( fS = 67kHz, unmodulated ).

4. ACI (Adjacent Channel Interference )

114 = VO(signal,@1KHz) / VO(spurious, @4KHz) ; fs = 110KHz - (3x38KHz)

a

a

190 = VO(signal,@1KHz) / VO(spurious, @4KHz) ; fs = 186KHz - (5x38KHz)

measured with: 90% mono signal; 9% pilot signal; fm=1kHz; 1% spurious signal ( fS = 110kHz or 186kHz, unmodulated).

5. All thresholds are measured inTestmode at the quality output. The thresholds are calculated by
V

- V

V

NBTH

PEAK

PEAK

is adjusted by applying a 150kHz sinewave at MPXIN.

23/76

Electrical specifications TDA7540N

Figure 3. Trigger threshold vs. V

VTH

Min. Trig. T hreshold

280 mV

8 STEPS

147 mV

0.8 V

PEAK

Figure 4. Deviation controlled trigger adjustment

V

PEAK

[V ]

OP

Noise Controlled Tr ig. Threshold

1200 mV (00)

950 mV (01)

700 mV (10)

450 mV (11)

V

Peak1.5 V

00

2.0
01

1.5

10

1.0

0.8

11

20 32.5 45 75

Figure 5. Field strength controlled trigger adjustment

V

PEAK

MONO STER EO

≈

3V

2.0V (00 )

1.6V(01)

NOIS E

ATC_SB OFF (11)

1.4V(10)

Detector off

DEVIATION [KHz]

0.8V

noisy sig nal go od signa l

24/76

E'

TDA7540N Electrical specifications

3.3.5 PLL Section

Table 9. PLL electrical characteristics

(T

= 25°C, V

amb

f

= 98MHz, dev. = 40kHz, f

RF

otherwise specified).

Symbol Parameter Test conditions Min. Typ. Max. Unit

Output of tuning voltages (TV1,TV2)

CC1

= V

CC2

= V

CC3

MOD

= V

CCST

= 1kHz, f

= V

CCVCO

= 10.25MHz, in application circuit, unless

Xtal

= V

CCMIX1

= V

CCMIX2

= V

CCIF1

= 8.5V,

R

R

V

OUT

OUT

OUT

Output voltage TVO 0.5 V

-0.5 V

CC3

Output impedance TVMODE=0 32 40 48 kΩ

Output impedance TVMODE=1 16 20 24 kΩ

Xtal reference oscillator

f

LO

C

Step

C

max

Δf/f Deviation versus VCC2

Reference frequency C

= 15pF 10.25 MHz

Load

Min. cap step XTAL 0.75 pF

Max. cap XTAL 23.25 pF

ΔV

= 1V 1.5 ppm/V

CC2

Δf/f Deviation versus temp -40°C < T < +85°C 0.2 ppm/K

Loop filter input/output

-I

I

V

V

I

OUT

I

OUT

IN

IN

OL

OH

Input leakage current VIN = GND, PD

V

= VREF1

Input leakage current

Output voltage Low I

Output voltage High I

Output current, sink V

Output current, source V

IN

PD

= Tristate

OUT

= -0.2mA 0.05 0.5 V

OUT

= 0.2mA

OUT

= 1V to V

OUT

= 1V to V

OUT

= Tristate -0.1 0.1 μA

OUT

-0.1 0.1 μA

V

-

V

CC3

0.5

-1V 10 mA

CC3

-1V -10 mA

CC3

CC3

0.05

-

Voltage controlled oscillator (VCO)

V

f

VCOmin

f

VCOmax

C/N Carrier to Noise

Minimum VCO frequency 50 MHz

Maximum VCO frequency 260 MHz

f

= 200MHz, Δf=1KHz,

VCO

B=1Hz, closed loop

80 dBc

SSTOP, INLOCK, ISSSTATUS outputs (open collector)

V Output voltage low I = -200

μA0.20.5V

V Output voltage high 5 V

-I Output leakage current V = 5V -0.1 0.1 μA

I Output current, sink V = 0.5V-5V 1 mA

Switching outputs S1, S2 (open collector SMODE=1)

V Output voltage low I = -5mA 0.2 0.5 V

25/76

Electrical specifications TDA7540N

Table 9. PLL electrical characteristics (continued)

(T

= 25°C, V

amb

f

= 98MHz, dev. = 40kHz, f

RF

CC1

= V

CC2

= V

CC3

MOD

= V

CCST

= 1kHz, f

= V

CCVCO

= 10.25MHz, in application circuit, unless

Xtal

= V

CCMIX1

= V

CCMIX2

= V

CCIF1

= 8.5V,

otherwise specified).

Symbol Parameter Test conditions Min. Typ. Max. Unit

V Output voltage high V

CC1

V

-I Output leakage current V = 5V -0.5 0.5 μA

I Output current, sink V = 0.5V-V

CC

7mA

Switching outputs S1, S2 (Open emitter SMODE=0)

V Output voltage low I = 0μA0.10.3V

V Output voltage high I = 1mA

V

CC1

-1

V

I Output current, sink V = 5V 7 mA

26/76

TDA7540N Functional description

4 Functional description

4.1 FM section

4.1.1 Mixer1, AGC and 1.IF

FM quadrature I/Q-mixer converts FM RF to IF1 of 10.7MHz. The mixer provides inherent
image rejection and wide dynamic range with low noise and large input signal performance.
The mixer1 tank can be adjusted by software (IF1T). For accurate image rejection the
phase-error of I/Q can be compensated by software (PH)

It is capable of tuning the US FM, US weather, Europe FM, Japan FM and East Europe FM
bands

– US FM = 87.9 to 107.9 MHz
– US weather = 162.4 to 162.55 MHz
– Europe FM = 87.5 to 108 MHz
– Japan FM = 76 to 91 MHz
– East Europe FM = 65.8 to 74 MHz

The AGC operates on different sensitivities and bandwidths in order to improve the input
sensitivity and dynamic range. AGC thresholds are programmable by software
(RFAGC,IFAGC,KAGC). The output signal is a controlled current for pin diode attenuator.

A 10.7MHz programmable amplifier (IFG1) correct the IF ceramic insertion loss and the
costumer level plan application.

4.1.2 Mixer2, limiter and demodulator

In this 2nd mixer stage the first 10.7MHz IF is converted into the second 450kHz IF. A multi­stage limiter generates signals for the complete integrated demodulator including spike
cancellation (DNB). MPX output DC offset versus noise DC level is correctable by software
(DEM), if tuner softmute is activated.

4.1.3 Quality detection and ISS

Fieldstrength

Parallel to mixer2 input a 10.7MHz limiter generates a signal for digital IF counter and a
fieldstrength output signal. This internal unweighted fieldstrength is used for keying AGC,
adjacent channel and multipath detection and is available at PIN22 (FSU) after +6dB buffer
stage. It is possible to combinate the IF counter result with this FSU via programmable
comparator (SSTH). The behaviour of FSU signal can be corrected for DC offset (SL) and
slope (SMSL). The generated unweighted fieldstrength is externally filtered and used for
softmute function and generation of ISS filter switching signal for weak input level (sm).

Adjacent channel detector

The input of the adjacent channel detector is AC coupled from internal unweighted
fieldstrength. A programmable highpass or bandpass (ACF) and amplifier (ACG) as well as
rectifier determines the influences. This voltage is compared with adjustable comparator1
thresholds (ACWTH, ACNTH). The output signal of this comparator generates a DC level at
PIN27 by programmable time constant. Time control (TISS) for a present adjacent channel

27/76

Functional description TDA7540N

is made by charge and discharge current after comparator1 in an external capacitance. The
charge current is fixed and the discharge current is controlled by I
produces digital signals (ac, ac+) in an additional comparator4. The adjacent channel
information is available as analog output signal after rectifier and +8dB output buffer.

2

C Bus. This level

Multipath detector

The input of the multipath detector is AC coupled from internal unweighted fieldstrength. A
programmable bandpass (MPF) and amplifier (MPG) as well as rectifier determines the
influences. This voltage is compared with an adjustable comparator2 thresholds (MPTH).
The output signal of this comparator2 is used for the "Milano" effect. In this case the
adjacent channel detection is switched off. The "Milano" effect is selectable by I
(MPOFF). The multipath information is available as analog output signal after rectifier and
+8dB output buffer.

2

C Bus

450kHz IF narrow bandpass filter (ISS filter)

The device gets an additional 450KHz IF narrow bandpass filter for suppression of noise
and adjacent channel signal influences. This narrow filter has three switchable bandwidthes,
narrow range of 80kHz, mid range of 120kHz and 30KHz for weather band information.
Without ISS filter the IF bandwidth (wide range) is defined only by ceramic filter chain. The
filter is located between mixer2 and 450kHz limiter stage. The centre frequency is matched
to the demodulator center frequency.

Deviation detector

In order to avoid distortion in audio output signal the narrow ISS filter is switched OFF for
present overdeviation. Hence the demodulator output signal is detected. A lowpass filtering
and peak rectifier generates a signal that is defined by software controlled current (TDEV) in
an external capacitance.

This value is compared with a programmable comparator3 thresholds (DWTH, DTH) and
generates two digital signals (dev, dev+). For weak signal condition deviation threshold is
dependent on FSWO.

ISS switch logic

All digital signals coming from adjacent channel detector, deviation detector and softmute
are acting via switching matrix on ISS filter switch. The IF bandpass switch mode is
controlled by software (ISSON, ISS30, ISS80, CTLOFF). The switch ON of the IF bandpass
is also available by external manipulation of voltage at PIN27. Two application modes are
available (APPM).

The conditions are described in Ta bl e 5 2 .

4.1.4 Soft mute control

The filtered fieldstrength (FSWO) signal is the reference for mute control. The startpoint and
mute depth are programmable (SMTH, SMD) in a wide range. The time constant is defined
by external capacitance. Additional adjacent channel mute function is supported. A
highpass filter with -3dB threshold frequency of 100kHz, amplifier and peak rectifier
generates an adjacent noise signal from MPX output with the same time constant for
softmute. This value is compared with comparator5 thresholds (ACM). For present strong
adjacent channel the MPX signal is additional attenuated (ACMD).

28/76

TDA7540N Functional description

4.2 AM section

The up/down conversion is combined with gain control circuit sensing three input signals,
narrow band information at PIN 54, upconversion signal (IF2AGC) at PIN 71and wide band
information (RFAGC) at PIN 4.This gain control gives two output signals. The first one is a
current for pin diode attenuator and the second one is a voltage for preamplifier. Time
constant of RF- and IF-AGC is defined by internal 100k resistor and external capacitor at
PIN 67. The intervention points for AGC (DAGC,WAGC) are programmable by software.

In order to avoid a misbehaviour of AGC intervention point it is important to know that the
DAGC threshold has to be lower than WAGC threshold !

The oscillator frequency for upconversion-mixer1 is generated by dividing the VCO
frequency after VCO divider (VCOD) and AM predivider(AMD).

Two 10,7MHz ceramic filters before mixer2 input increases 900KHz attenuation.In mixer2
the IF1 is down converted into the IF2 450kHz. After filtering by ceramic filter a 450kHz
amplifier is included with an additional gain control of IF2 below DAGC threshold. Time
constant is defined by capacitance at PIN 78.

Mixer1 and mixer2 tanks are software controlled adjustable (IF1T, IF2T).

The demodulator is a peak detector to generate the audio output signal.

A separate output is available for AMIF stereo (AMST).

AM IF noise blanker

In order to remove in AM short spikes a noise cancellation conception is used in 450KHz IF
AM level. The advantage is to avoid long narrow AGC- and demodulator- time constants,
wich enlarge spike influences on audio signal and makes difficult to remove it in audio path.

The 10.7MHz AM IF signal generates before 10.7 MHz ceramic filter via limitation an
unweighted fieldstrenght signal including slope of noise spike. The comparison of these
detected slope between fast and slow rectifier ignores audio modulation whereby the
threshold of slow rectifier is programmable (AINBT). A comparator activates a pulse
generator.

The duration of this pulse is software programmable (AINT) and is smooth blanking out the
spikes in 450KHz AM mixer2. Additionally this funtionality is controlled by narrow AM
fieldstrenght (AINBD).

4.3 Stereodecoder

4.3.1 Decoder

The stereo decoder-part of the TDA7540N (see Figure 14) contains all functions necessary
to demodulate the MPX-signal like pilot tone-dependent MONO/STEREO-switching as well
as "stereoblend" and "highcut". Adaptations like programmable input gain, roll-off
compensation, selectable deemphasis time constant and a programmable field strength
input allow easy adaption to different applications.

th

The 4
and noise and acts as an anti-aliasing filter for the following switch capacitor filters.

order input filter has a corner frequency of 80kHz and is used to attenuate spikes

29/76

Functional description TDA7540N

Demodulator

In the demodulator block the left and the right channel are separated from the MPX-signal.
In this stage also the 19-kHz pilot tone is canceled. For reaching a high channel separation
the TDA7540 offers an I2C-bus programmable roll-off adjustment, which is able to
compensate the low pass behavior of the tuner section. Within the compensation range an
adjustment to obtain at least 40dB channel separation is possible. The bits for this
adjustment are located together with the level gain adjustment in one byte. This gives the
possibility to perform an optimization step during the production of the car radio where the
channel separation and the header are trimmed.

In addition to that the FM signal can be inverted.

Deemphasis and highcut

The deemphasis low pass allows to choose between a time constant of 50µs/ 75μs
(DEEMP) and 25μs/37.5μs (DESFT). The highcut control range will be in both cases τ
2xτ

. Inside the highcut control range (between VHCH and VHCL) the LEVEL signal is

Deemp

converted into a 5-bit word, which controls the low pass time constant between

τ

Deemp

...3xτ

. Thereby the resolution will remain always 5 bits independently of the

Deemp

absolute voltage range between the VHCH- and VHCL-values.

The highcut function can be switched off by I

2

C-bus .

HC

=

In AM mode (AMON = 1) the bits DEEMP and DESFT together with the AM corner
frequency bits (AMCF1...5) can be used as programmable AM frequency response. The
maximum corner frequency is defined by τ

, the minimum is defined by 3xτ

Deemp

Deemp

19kHz PLL and pilot tone detector

The PLL has the task to lock on the 19kHz pilot tone during a stereo-transmission to allow a
correct demodulation. The included pilot tone-detector enables the demodulation if the pilot
tone reaches the selected pilot tone threshold V

. Two different thresholds are

PTHST

available. The status of the detector output can be checked by reading the status byte of the
TDA7540N via I

2

C-bus or by reading the STEREO pin (pin 25).

Field strength control

The field strength input is used to control the highcut- and the stereoblend-function. In
addition the signal can be also used to control the noise blanker thresholds and as input for
the multipath detector.

Level-input and -gain

As level input for the stereo decoder is used the FSU voltage (pin22). Appling a capacitor at
FSTC (pin33) a desired time constant can by reached together with the internal resistor of
10k between FSU pin and FSTC pin.

In addition to that the LEVEL signal is low pass filtered internally in order to suppress
undesired high frequency modulation on the highcut- and stereoblend-function . The filter is
a combination of a 1
order switched capacitor low pass at 2.2kHz. The second stage is a programmable gain
stage to adapt the LEVEL signal internally . The gain is widely programmable in 8 steps
from 0dB to 4,7dB (step=0.67dB). These 3bits are located together with the Roll-Off bits in
the "Stereo decoder 8"-byte to simplify a possible adaptation during the production of the
car radio.

st

-order RC-low pass at 53kHz (working as anti-aliasing filter) and a 1st-

30/76

TDA7540N Functional description

L

t

r

τ

Stereoblend control

The stereoblend control block converts the internal LEVEL-voltage into a demodulator
compatible analog signal, which is used to control the channel separation between 0dB and
the maximum separation. Internally this control range has a fixed upper limit, which is the
internal reference voltage

V

in 4% steps (see Figure 6).

REF1

To adjust the external LEVEL-voltage to the internal range two values must be defined: the
LEVEL gain L

and VSBL. To adjust the voltage where the full channel separation is

G

reached (VST) the LEVEL gain L
estimate the gain:

The MONO-voltage VMO (0dB channel separation) can be chosen selecting VSBL.

Figure 6. Relation between internal and external level-voltagees and setup of

stereoblend

V

. The lower limit can be programmed between 29 and 58% of

REF1

has to be defined. The following equation can be used to

G

L

G

= V

/FSU@full stereo

REF1

The stereo blend function can be switched ON/OFF using bit Addr25<d2>. Please note that
in AM it must be switched in forced mono!

Highcut control

The highcut control set-up is similar to the stereoblend control set-up: the starting point
VHCH can be set with 2 bits to be 42, 50, 58 or 66% of V
to be 11, 18.3, 25.7 or 33% of VHCH (see Figure 7).

Figure 7. Highcut characteristics

owpass

ime con stant

3

•
Deem p

Deem p

VHCL VHC

whereas the range can be set

REF1

HFieldst

ength

31/76

Functional description TDA7540N

4.3.2 Functional description of the noise blanker

In the automotive environment spikes produced by the ignition or for example the wiper­motor disturb the MPX-signal. The aim of the noise blanker part is to cancel the audible
influence of the spikes. Therefore the output of the stereo decoder is held at the actual
voltage for a time between 22
blanker is given inFigure 15.

In a first stage the spikes must be detected but to avoid a wrong triggering on high
frequency (white) noise a complex trigger control is implemented. Behind the trigger stage a
pulse former generates the "blanking"-pulse. An own biasing circuit supplies the noise
blanker in order to avoid any cross talk to the signal path.

Trigg er pa th

The incoming MPX signal is high pass filtered, amplified and rectified. This second order
high pass filter has a corner-frequency of 140kHz. The rectified signal, RECT, is low pass
filtered to generate a signal called PEAK. Also noise with a frequency 140kHz increases the
PEAK voltage. The resulting voltage can be adjusted by use of the noise rectifier discharge
current. The PEAK voltage is fed to a threshold generator, which adds to the PEAK-voltage
a DC-dependent threshold VTH. Both signals, RECT and PEAK+VTH are fed to a
comparator, which triggers a re-triggerable monoflop. The monoflop's output activates the
sample-and-hold circuits in the signal path for the selected duration.

μs and 38μs (programmable). The block diagram of the noise

Automatic noise controlled threshold adjustment (Figure 3)

There are mainly two independent possibilities for programming the trigger threshold:

1. the low threshold in 8 steps (NBLTH)

2. and the noise adjusted threshold in 4 steps (NBCTH).

The low threshold is active in combination with a good MPX signal without any noise; the
PEAK voltage is less than 1V. The sensitivity in this operation is high.

If the MPX signal is noisy (low fieldstrength) the PEAK voltage increases due to the higher
noise, which is also rectified. With increasing of the PEAK voltage the trigger threshold
increases, too. This particular gain is programmable in 4 steps (NBCTH).

Automatic threshold control by the stereoblend voltage (Figure 5)

Besides the noise controlled threshold adjustment there is an additional possibility for
influencing the noise blanker trigger threshold using the bits NBFS. This influence depends
on the stereoblend control.

The point where the MPX signal starts to become noisy is fixed by the RF part. This point is
also the starting point of the normal noise-controlled trigger adjustment. But in some cases
the noise blanker can create a wrong triggering, which create distortion, already in the
region of mono/stereo transition. Therefore a opportunity to control the PEAK voltage by the
stereo blend function it is implemented.

Over deviation detector (Figure 4)

If the system is tuned to stations with a high deviation the noise blanker can trigger on the
higher frequencies of the modulation. To avoid this wrong behavior, which causes noise in
the output signal, the noise blanker offers a deviation-dependent threshold adjustment. By
rectifying the MPX signal a further signal representing the actual deviation is obtained. It is

32/76

TDA7540N Functional description

used to increase the PEAK voltage. Offset and gain of this circuit are programmable in 3
steps (NBDTH) of the stereo decoder-byte (the first step turns off the detector).

Multipath-level

To react on high repetitive spikes caused by a Multipath-situation, the discharge-time of the
PEAK voltage can be decreased depending on the voltage-level at Pin MPout. There are
two ways to do this. One way is to switch on the linear influence of the Multipath-Level on the
PEAK-signal . In this case the discharge slew rate is 1V/ms

1)

. The second possibility is to
activate a function, which switches to the 18k discharge if the Multipath-Level is below 2.5V.
If multipath influence on noise blanker is switched ON than MPF bit has to be set to 0.

1)

The slew rate is measured with R

Discharge

=infinite and V

MPout

=2.5V

AM Mode of Noise Blanker

The TDA7540N offers an AM audio noise blanker too.

If the AM noise blanker is used the AM audio delay filter and the AM audio filter must be
switched on. It is not recommented to use the AM noise blanker without to use the AMIF
noiseblanker inside the tuner.

The noise blanker is activated if the spike is bigger than a fixed threshold

In order to blank the whole spike in AM mode the hold time of the S&H circuit is much longer
than in FM mode (640µs -1.2ms).

4.3.3 Functional description of the multipath-detector

Using the internal Multipath-Detector the audible effects of a multipath condition can be
minimized. A multipath-condition is detected by rectifying the 19kHz spectrum in the
fieldstrength signal. An external capacitor is used to define the attack- and decay-times (see
block diagram, Figure 16). The MP_OUT-pin is used as detector-output connected to a
capacitor of about 47nF. Using this configuration an external adaptation to the user's
requirement is possible without affecting the "normal" fieldstrength input (LEVEL) for the
stereo decoder.

To keep the old value of the Multipath Detector during an AF-jump, the MP-Hold switch can
disconnect the external capacitor. This switch is controlled directly by the AFS-Pin.

Selecting MPION the channel separation is automatically reduced during a multipath
condition according to the voltage appearing at the MP_OUT-pin.

Programming

To obtain a good multipath performance an adaptation is necessary. Therefore the gain of
the first 19kHz-bandpass is programmable in two steps (MPG), the gain of the second
19kHz-bandpass is programmable in four steps (MPBPG) and the rectifier gain is
programmable in four steps(MPRG). Please note that the frequency of the first multipath
bandpass (MPF) must be set to 19kHz! The attack- and decay-times can be set by the
external capacitor value and the multipath detector charge current MPCC.

4.3.4 Quality detector

The TDA7540N offers a quality detector output, which gives a voltage representing the FM­reception conditions. To calculate this voltage the MPX-noise and the multipath-detector
output are summed according to the following formula:

33/76

Functional description TDA7540N

VQual = 0.8b (VNoise-0.8 V)+ a (V

The noise-signal is the PEAK-signal without additional influences (see noise blanker
description). The factor 'a' can be programmed from 0.6 to 1.05(QDC) and the factor b can
be programmed from 6dB to 15dB ( QNG). The output is a low impedance output able to
drive external circuitry as well as simply fed to an AD-converter for RDS applications.

4.3.5 AFS control and stereo decoder mute

The TDA7540N is supplied with several functionality to support AF-checks using the stereo
decoder. The additional pin (AFS) is implemented in order to speed up the stereo decoder
AF-functions compared to IIC controlling.

The block diagramm of AFS function is shown in Figure 17.

In order to separate the different functions of the AFS pin, two different logic thresholds are
implemented. Below the higher threshold voltage (2.4V) only the multipath-detector is
switched into small time constant (internal logical signal MPfast).

Below the lower threshold voltage (0.8V) the full AFS function is activated. The MPXIN pin is
switched into high impedance mode (internal signal AFSMute), which avoids any clicks
during the jump condition. If the stereo decoder is not muted, it is possible at the same time
to evaluate the noise- and multipath-content of the alternate frequency using the Quality
detector output.

Furthermore the AFS pin does also freeze the condition of pilot locking and magnitude
(internal signal PDhold). The Pdhold signal is defined by V
PDH signal.

REF1

th1

-VMpout).

or V

, dependent on the

th2

4.4 PLL and IF counter section

4.4.1 PLL frequency synthesizer block

This part contains a frequency synthesizer and a loop filter for the radio tuning system. Only
one VCO is required to build a complete PLL system for FM world tuning and AM
upconversion (Figure 9). For auto search stop operation an IF counter system is available.

The PLL counter works in a two stages configuration. The first stage is a swallow counter
with a two modulus (32/33) precounter. The second stage is an 11-bit programmable
counter.

The circuit receives the scaling factors for the programmable counters and the values of the
reference frequencies via an I
adjustable internal (XTAL) oscillator followed by the reference divider. The main reference
and step-frequencies are free selectable (RC, PC).

Output signals of the phase detector are switching the programmable current sources. The
loop filter integrates their currents to a DC voltage.

The values of the current sources are programmable by 6 bits also received via the I
(A, B, CURRH, LPF).

To minimize the noise induced by the digital part of the system, a special guard
configuration is implemented.

The loop gain can be set for different conditions by setting the current values of the
chargepump generator.

2

C-Bus interface.The reference frequency is generated by an

2

C Bus

34/76

TDA7540N Functional description

Frequency generation for phase comparison

The RF signals applies a two modulus counter (32/33) pre-scaler, which is controlled by a 5­bit A-divider. The 5-bit register (PC0 to PC4) controls this divider. In parallel the output of the
prescaler connects to an 11-bit B-divider. The 11-bit PC register (PC5 to PC15) controls this
divider

Dividing range behind VCO divider:

f

= [33 x A + (B + 1 - A) x 32] x f

VCOdiv

f

= (32 x B + A + 32) x f

VCOdiv

REF

REF

Important: For correct operation: A ≤ 32; B ≥ A

Three state phase comparator

The phase comparator generates a phase error signal according to phase difference
between f

SYN

and f

. This phase error signal drives the charge pump current generator.

REF

Charge pump current generator

This system generators signed pulses of current. The phase error signal decides the
duration and polarity of those pulses. The current absolute values are programmable by A
register for high current and B register for low current.

Inlock detector

Switching the chargepump in low current mode can be done either via software or
automatically by the inlock detector, by setting bit LDENA to "1".

After reaching a phase difference about lower than 40nsec the chargepump is forced in low
current mode. A new PLL divider alternation by I
high current mode.

Low noise CMOS op-amp

An internal voltage divider at pin VREF2 connects the positive input of the low noise op­amp. The charge pump output connects the negative input. This internal amplifier in
cooperation with external components can provide an active filter. The negative input is
switchable to three input pins, to increase the flexibility in application. This feature allows two
separate active filters for different applications.

While the high current mode is activated LPHC output is switched on.

4.4.2 IF counter block

The aim of IF counter is to measure the intermediate frequency of the tuner for AM and FM
mode. The input signal for FM and AM upconversion is the same 10.7MHz IF level after
limiter. AM 450KHz signal is coming from narrow filtered IF2 before demodulation. A switch
controlled by IF counter mode (IFCM) is choosing the input signal for IF counter.

The grade of integration is adjustable by eight different measuring cycle times. The
tolerance of the accepted count value is adjustable, to reach an optimum compromise for
search speed and precision of the evaluation.

2

C-Bus will switch the chargepump in the

The IF-counter mode

The IF counter works in 3 modes controlled by IFCM register.

35/76

Functional description TDA7540N

Sampling timer

A sampling timer generates the gate signal for the main counter. The basically sampling
time are in FM mode 6.25kHz (t

=160μs) and in AM mode 1kHz (t

TIM

=1ms). This is

TIM

followed by an asynchronous divider to generate several sampling times.

Intermediate frequency main counter

This counter is a 11 - 21-bit synchronous autoreload down counter. Five bits (CF) are
programmable to have the possibility for an adjust to the centre frequency of the IF-filter.
The counter length is automatic adjusted to the chosen sampling time and the counter mode
(FM, AM-UPC, AM).

At the start the counter will be loaded with a defined value which is an equivalent to the
divider value (t

SamplexfIF

If a correct frequency is applied to the IF counter frequency input at the end of the sampling
time the main counter is changing its state from 0h to 1FFFFFh.

This is detected by a control logic and an external search stop output is changing from LOW
to HIGH. The frequency range inside which a successful count result is adjustable by the
EW bits.

t

= (CF + 1696+1) / f

CNT

t

= (CF + 10688+1) / fIF AM up conversion mode

CNT

t

= (CF + 488+1) / f

CNT

).

IF

IF

FM mode

AM mode

Counter result succeeded:
t

≥ t
≤ t

CNT
CNT

- t
+ t

ERR

ERR

TIM

t

TIM

Counter result failed:
t

> t

TIM

t

< t

TIM

t

= IF timer cycle time (sampling time)

TIM

t

CNT

t

ERR

+ t

CNT
CNT

- t

ERR

ERR

= IF counter cycle time
= discrimination window (controlled by the EW registers)

The IF counter is only started by inlock information from the PLL part. It is enabled by
software (IFENA).

Adjustment of the measurement sequence time

The precision of the measurements is adjustable by controlling the discrimination window.
This is adjustable by programming the control registers EW.

The measurement time per cycle is adjustable by setting the registers IFS.

Adjust of the frequency value

The center frequency of the discrimination window is adjustable by the control registers CF.

36/76

TDA7540N Functional description

4.5 I2C-Bus interface

The TDA7540N supports the I2C-Bus protocol. This protocol defines any device that sends
data onto the bus as a transmitter, and the receiving device as the receiver. The device that
controls the transfer is a master and device being controlled is the slave. The master will
always initiate data transfer and provide the clock to transmit or receive operations.

Data transition

Data transition on the SDA line must only occur when the clock SCL is LOW. SDA transitions
while SCL is HIGH will be interpreted as START or STOP condition.

Start condition

A start condition is defined by a HIGH to LOW transition of the SDA line while SCL is at a
stable HIGH level. This "START" condition must precede any command and initiate a data
transfer onto the bus. The device continuously monitors the SDA and SCL lines for a valid
START and will not response to any command if this condition has not been met.

Stop condition

A STOP condition is defined by a LOW to HIGH transition of the SDA while the SCL line is at
a stable HIGH level. This condition terminates the communication between the devices and
forces the bus-interface of the device into the initial condition.

Acknowledge

Indicates a successful data transfer. The transmitter will release the bus after sending 8 bits
of data. During the 9th clock cycle the receiver will pull the SDA line to LOW level to indicate
it receive the eight bits of data.

Data transfer

During data transfer the device samples the SDA line on the leading edge of the SCL clock.
Therefore, for proper device operation the SDA line must be stable during the SCL LOW to
HIGH transition.

Device addressing

To start the communication between two devices, the bus master must initiate a start
instruction sequence, followed by an eight bit word corresponding to the address of the
device it is addressing.

The most significant 6 bits of the slave address are the device type identifier.

The TDA7540N device type is fixed as "110001".

The next significant bit is used to address a particular device of the previous defined type
connected to the bus.

The state of the hardwired PIN 59 defines the state of this address bit. So up to two devices
could be connected on the same bus. When PIN 59 is connected to VCC2 and a resistor at
PIN 55 versus ground of about 5.6k Ohm the address bit “1” is selected. In this case the AM
part doesn’t work. Otherwise the address bit “0” is selected (FM and AM is working).
Therefor a double FM tuner concept is possible.

37/76

Functional description TDA7540N

The last bit of the start instruction defines the type of operation to be performed:

– When set to "1", a read operation is selected
– When set to "0", a write operation is selected

The TDA7540N connected to the bus will compare their own hardwired address with the
slave address being transmitted, after detecting a START condition. After this comparison,
the TDA7540N will generate an "acknowledge" on the SDA line and will do either a read or a
write operation according to the state of R/W bit.

Write operation

Following a START condition the master sends a slave address word with the R/W bit set to
"0". The device will generate an "acknowledge" after this first transmission and will wait for a
second word (the word address field). This 8-bit address field provides an access to any of
the 64 internal addresses.

Upon receipt of the word address the TDA7540N slave device will respond with an
"acknowledge". At this time, all the following words transmitted to the TDA7540N will be
considered as Data. The internal address will be automatically incremented up to hex40 in
page mode. Than again subaddresse hex60 has to be transmitted for following registers
above 32.

After each word receipt the TDA7540N will answer with an "acknowledge".

Read operation

If the master sends a slave address word with the R/W bit set to "1", the TDA7540N will
transit one 8-bit data word. This data word includes the following informations:

bit0 (ISS filter, 1 = ON, 0 = OFF)
bit1 (ISS filter bandwidth, 1 = 80kHz, 0 = 120kHz)
bit2 (STEREO,1 = STEREO, 0 = MONO)
bit3 (1 = PLL is locked in , 0 = PLL is locked out).
bit4 (fieldstrength indicator, 1 = lower as softmute threshold, 0 = higher as softmute

threshold)
bit5 (adjacent channel indicator, 1 = adjacent channel present, 0 = no adjacent

channel)
bit6 (deviation indicator, 1 = strong overdeviation present, 0 = no strong overdeviation)
bit7 (deviation indicator, 1 = overdeviation present, 0 = no overdeviation)

38/76

TDA7540N Software specification

5 Software specification

The interface protocol comprises:

- start condition (S)

- chip address byte

- subaddress byte

- sequence of data (N bytes + Acknowledge)

- stop condition (P)

The pagermode is only working up to byte 31. After byte 31 it is need to send again the chip
address followed by the subaddress 32 and the databytes starting from 32 up to 39!

5.1 Address organization

Table 10. Address organization

Function Addr 7 6 5 4 3 2 1 0

CHARGEPUMP 0 FMSEEK CURRH B1 B0 A3 A2 A1 A0

PLL COUNTER

IFC CTRL 1 5 LDENA CASF IFCM1 IFCM0 IFENA IFS2 IFS1 IFS0

IFC CTRL 2 6 EW2 EW1 EW0 CF4 CF3 CF2 CF1 CF0

AM CTL 7 LM TVMODE TV2WB TV1WB AMD1 AMD0 AMST AMSEEK

QUALITYISS 8 TISS2 TISS1 TISS0 --- ISS30 ISS80 ISSON CTLOFF

QUALITY AC 9 ACNTH1 ACNTH0 ACWTH2 ACWTH1 ACWTH0 ACG ACF ---

QUALITY MP 10 MPAC APPM2 APPM1 MPTH1 MPTH0 MPG MPF MPOFF

QUALITYDEV 11 BWCTL DTH1 DTH0 DWTH1 DWTH0 TDEV2 TDEV1 TDEV0

MUTE1 12 MENA SMD3 SMD2 SMD1 SMD0 SMTH2 SMTH1 SMTH0

MUTE2 13 F100K ACM3 ACM2 ACM1 ACM0 ACMD1 ACMD0 SMCTH

VCO/PLLREF 14 LPF AMON RC2 RC1 RC0 VCOD2 VCOD1 VCOD0

1 PC7 PC6 PC5 PC4 PC3 PC2 PC1 PC0

2 PC15 PC14 PC13 PC12 PC11 PC10 PC9 PC8

TV1 3 TV1O7 TV1O6 TV1O5 TV1O4 TV1O3 TV1O2 TV1O1 TV1O0

TV2 4 TV2O7 TV2O6 TV2O5 TV2O4 TV2O3 TV2O2 TV2O1 TV2O0

39/76

Software specification TDA7540N

Table 10. Address organization (continued)

Function Addr 7 6 5 4 3 2 1 0

FMAGC 15 RFKAGC KAGC2 KAGC1 KAGC0 IFAGC1 IFAGC0 RFAGC1 RFAGC0

AMAGC 16 DAGC3 DAGC2 DAGC1 DAGC0 WAGC3 WAGC2 WAGC1 WAGC0

DEM ADJ 17 DNB1 DNB0 DEM5 DEM4 DEM3 DEM2 DEM1 DEM0

LEVEL 18 ODSW ODCUR SMSL SL4 SL3 SL2 SL1 SL0

IF1/XTAL 19 XTAL4 XTAL3 XTAL2 XTAL1 XTAL0 IFG11 IFG10 XTLIM

TANK ADJ 20 IF1T3 IF1T2 IF1T1 IF1T0 IF2T3 IF2T2 IF2T1 IF2T0

I/Q ADJ 21 SMO1 SMO0 --- --- PH3 PH2 PH1 PH0

AMIFNB 22 AINT1 AINT0 AINBD1 AINBD0 AINBT3 AINBT2 AINBT1 AINBT0

SCTRL 23 SSTH3 SSTH2 SSTH1 SSTH0 S2MODE S2 S1MODE S1

STD1 24 STVCO1 STVCO0 NBT1 NBT0 SI TFCKL NBFT TSMA

STD2 25 STING1 STING0 DEEMP PTH NBPC MS STDON STDM

STD3 26 NBDTH1 NBDTH0 NBON NBCTH1 NBCTH0 NBLTH2 NBLTH1 NBLTH0

STD4 27 NBSMP VHCL1 VHCL0 VHCH1 VHCH0 MAXHC1 MAXHC0 HCON

STD5 28 MPPC QDC1 QDC0 NBFS1 NBFS0 SBC2 SBC1 SBC0

STD6 29 MPRG1 MPRG0 MPCC MPION MPBPG1 MPBPG0 NBRR1 NBRR0

STD7 30 AMAF LG2 LG1 LG0 ROC3 ROC2 ROC1 ROC0

STD8 31 AMNBD AMNBFO AMNBHP PDH AFSM AFSON QNG1 QNG0

STD9 32 AMCF4 AMCF3 AMCF2 AMCF1 AMCF0 DESFT --- ---

TESTTU1 33 OUT20 ISSIN TOUT TIN1 CLKSEP TEST3 TEST2 TEST1

TESTTU2 34 OUT7 OUT6 OUT5 OUT4 OUT3 OUT2 OUT1 OUT0

TESTTU3 35 --- TINACM TINMP TINAC OUT11 OUT10 OUT9 OUT8

TESTTU4 36 OUT19 OUT18 OUT17 OUT16 OUT15 OUT14 OUT13 OUT12

TESTTU5 37 TIN2 OUT27 OUT26 OUT25 OUT24 OUT23 OUT22 OUT21

TESTSTD 38 --- --- MUXST3 MUXST2 MUXST1 MUXST0 --- TST

FMDEMSB 39 VCOM PCM --- SBSH SBA SBTO SBW SBT

5.2 Control register function

Table 11. Control register function

Register Name Function

A Charge pump high current

ACF Adjacent channel filter select

ACG Adjacent channel filter gain

ACM Threshold for startpoint adjacent channel mute

ACMD Adjacent channel mute depth

40/76

TDA7540N Software specification

Table 11. Control register function (continued)

Register Name Function

ACNTH Adjacent channel narrow band threshold

ACWTH Adjacent channel wide band threshold

AFSM AFS influence on stereodecoder mute

AFSON AFS Pin enable

AINBD AM IF noise blanker desensitivity

AINBT AM IF noise blanker threshold

AINT AM IF noise blanking time

AMAF AM audio filter

AMD AM prescaler

AMCF AM corner frequency

AMIN AM IF1 input select

AMNBD AM audio delay for noise blanking

AMON AM-FM switch

AMSEEK Set short time constant of AGC in AM seek mode

AMST AM stereo select

APPM Application mode quality detection

B Charge pump low current

BWCTL ISS filter fixed bandwith (ISS80) in automatic control

CASF Check alternative station frequency

CF Center frequency IF counter

CLKSEP Clock separation (only for testing)

CTLOFF Switch off automatic control of ISS filter

CURRH Set current high charge pump

DAGC AM narrow band AGC threshold

DEEMP Stereodecoder deemphasis

DEM Demodulator offset

DESFT Stereodecoder deemphasis shift

DEVM Deviation detector mode

DNB Demodulator spike blanking threshold

DTH Deviation detector threshold for ISS filter “OFF”

DWTH Deviation detector threshold for ISS filter narrow/wide

EW Frequency error window IF counter

F100K Corner frequency of AC-mute high pass filter

FMSEEK ISS time constant change in FM seek mode

HCON High cut enable

41/76

Software specification TDA7540N

Table 11. Control register function (continued)

Register Name Function

IF1T FM/AM mixer1 tank adjust

IF2T AM mixer2 tank adjust

IFAGC FM IF AGC

IFCM IF counter mode

IFENA IF counter enable

IFG IF1 amplifier gain (10.7MHz)

IFS IF counter sampling time

ISSIN Test input for ISS filter

ISSON ISS filter “ON”

ISS30 ISS filter 30KHz weather band

ISS80 ISS filter narrow/mid switch

KAGC FM keying AGC

LDENA Lock detector enable

LG Level gain adjust in stereodecoder

LM Local mode FM seek stop

LPF Loop filter input select

MAXHC Maximum high cut

MENA Softmute enable

MPAC Adjacent channel control by multipath

MPCC Multipath detector charge current

MPBPG Multipath detector bandpass filter gain

MPF Multipath filter frequency

MPG Multipath filter gain

MPION Multipath internal influence enable

MPOFF Multipath control “OFF”

MPPC Multipath influence on peak discharge current

MPRG Multipath detector rectifier gain

MPTH Multipath threshold

MS Mono/Stereo switch automatically

MUXST Test multiplexer output stereodecoder

NBCTH Noise blanker noise controlled threshold

NBDTH Noise blanker deviation controlled threshold

NBFS Field strength controlled noise blanker

NBFT AM noise blanker fixed threshold

NBLTH Noise blanker low threshold

42/76

TDA7540N Software specification

Table 11. Control register function (continued)

Register Name Function

NBON Noise blanker enable

NBPC Noise blanker peak charge current

NBRR Noise blanker rectifier discharge resistor

NBSMP Strong multipath influence on noise blanker on/off

NBT Noise blanker time

ODCUR Current for overdeviation-correction

ODSW Overdeviation-correction enable

OUT Test output (only for testing)

PC Counter for PLL (VCO frequency)

PCM Pilot cancellation mode

PDH PD hold activation

PH I/Q mixer phase adjust

PTH Pilot threshold

QDC Quality detector coefficient

QNG Quality noise gain

RC Reference counter PLL

RFAGC FM RF AGC

RFKAGC FM RF keying AGC

ROC Roll-Off compensation

S Two mode switching output enable

SBA FM demodulator spike blanker attack mode

SBC Stereoblend control

SBSH FM demodulator spike blanker sample&hold mode

SBT FM demodulator spike blanker test mode

SBTO FM demodulator spike blanker toggle mode

SBW FM demodulator spike blanker window mode

SI Signal invertion

SL S meter slider

SMODE Two mode switching output

SMCTH Softmute capacitor threshold for ISS “ON”

SMD Softmute depth threshold

SMO Softmute reference voltage offset

SMSL S meter slope

SMTH Softmute startpoint threshold

SSTH Unweighted fieldstrenght threshold for seek stop

43/76

Software specification TDA7540N

Table 11. Control register function (continued)

Register Name Function

STDON Stereodecoder on/off if muted

STDM Stereodecoder mute enable

STING Stereodecoder ingain

STVCO Stereodecoder VCO adjust

TDEV Time constant for deviation detector

TEST Testing PLL/IFC (only for testing)

TFCKL Fast clock for testing audioprocessor

TIN Switch FSU PIN to TEST input (only for testing)

TINAC Test input adjacent channel (only for testing)

TINACM Test input adjacent channel mute (only for testing)

TINMP Test input multipath(only for testing)

TISS Time constant for ISS filter “ON”/”OFF”

TMSA Test mode stereodecoder and audioprocessor

TOUT Switch FSU PIN to Test output (only for testing)

TST Test stereodecoder enable

TVMODE Tuning voltage offset mode

TVO Tuning voltage offset for prestage

TVWB Tuning voltage offset for prestage (weather band mode)

VCOD VCO divider

VCOM Stereodecoder VCO mode

VCOON Enable Stereo Decoder VCO

VHCH Start level high cut

VHCL Stop level high cut

WAGC AM wide band AGC

XTAL Xtal frequency adjust

XTLIM Xtal amplitude limitation

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TDA7540N Software specification

Table 12. Subaddress

MSB LSB

I A5A4A3A2A1A0

000000Charge pump control

-------

100000STD9

-------

100111FMDEMSB

0 Page mode “OFF”

1 Page mode enable

5.2.1 Data byte specification

Table 13. Addr 0 Charge Pump Control

MSB LSB

d7 d6 d5 d4 d3 d2 d1 d0

0000High current = 0mA

Function

Function

0001High current = 0.5mA

0010High current = 1mA

0011High current = 1.5mA

-----

1111High current = 7.5mA

0 0 Low current = 0µA

0 1 Low current = 50µA

1 0 Low current = 100µA

1 1 Low current = 150µA

0 Select low current

1 Select high current

0 ISS time constant at PIN 27 available, FMSEEK “OFF”

1 ISS time constant at PIN 28 available, FMSEEK “ON”

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Software specification TDA7540N

Table 14. Addr 1 PLL counter 1 (LSB)

MSB LSB

d7 d6 d5 d4 d3 d2 d1 d0

00000000LSB = 0

00000001LSB = 1

00000010LSB = 2

---------

11111100LSB = 252

11111101LSB = 253

11111110LSB = 254

11111111LSB = 255

Table 15. Addr 2 PLL counter 2 (MSB)

MSB LSB

d7 d6 d5 d4 d3 d2 d1 d0

00000000MSB = 0

00000001MSB = 256

Function

Function

00000010MSB = 512

---------

11111100MSB = 64768

11111101MSB = 65024

11111110MSB = 65280

11111111MSB = 65536

Swallow mode: f

Table 16. Addr 3,4 TV1,2

VCO/fSYN

= LSB + MSB + 32

MSB LSB

Function

d7 d6 d5 d4 d3 d2 d1 d0

0000000Tuning Voltage Offset = 0

0000001TVO = 25mV

0000010TVO = 50mV

---------

1111111TVO = 3175mV

0-TVO

1+TVO

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TDA7540N Software specification

Table 17. Addr 5 IF counter control 1

MSB LSB

d7 d6 d5 d4 d3 d2 d1 d0

000t

001t

010t

011t

100t

101t

110t

111t

0 IF counter disable / stand by

1 IF counter enable

00 Not valid

0 1 IF counter FM mode

1 0 IF counter AM mode (450KHz)

1 1 IF counter AM mode (10.7MHz)

= 20.48ms (FM)128ms (AM )

Sample

= 10.24ms (FM)64ms (AM )

Sample

= 5.12ms (FM)32ms (AM )

Sample

= 2.56ms (FM)16ms (AM )

Sample

= 1.28ms (FM)8ms (AM )

Sample

= 640µs (FM)4ms (AM )

Sample

= 320µs (FM)2ms (AM)

Sample

= 160µs (FM)1ms (AM )

Sample

Function

0 Disable mute & AGC on hold in FM mode

1 Enable mute & AGC on hold in FM mode

0 Lock detector disable

1 Lock detector enable

Table 18. Addr 6 IF counter control 2

MSB LSB

d7 d6 d5 d4 d3 d2 d1 d0

00000f

00001

---------

01011f

---------

01111

---------

11111f

000 Not valid

= 10.60625MHz (FM) / 10.689MHz ; 449KHz (AM)

Center

= 10.61250MHz (FM) / 10.690MHz ; 450KHz (AM)

f

Center

recommended

= 10.67500MHz (FM) / 10.700MHz ; 460KHz (AM)

Center

f

= 10.70000MHz (FM) / 10.704MHz ; 464KHz (AM)

Center

recommended

= 10.80000MHz (FM) / 10.720MHz ;480KHz (AM)

Center

Function

001 Not valid

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Software specification TDA7540N

Table 18. Addr 6 IF counter control 2 (continued)

MSB LSB

Function

d7 d6 d5 d4 d3 d2 d1 d0

010 Not valid

011 Δf = 6.25kHz (FM)1kHz (AM) not recommended

100 Δf = 12.5kHz (FM) 2kHz (AM) not recommended

101 Δf = 25kHz (FM) 4kHz (AM)

110 Δf = 50kHz (FM) 8kHz (AM)

111 Δf = 100kHz (FM)16kHz (AM)

Table 19. Addr 7 AM control

MSB LSB

d7 d6 d5 d4 d3 d2 d1 d0

0 Multipath information available FM at PIN 24

1 AM stereo output available at PIN 24

0 0 Prescaler ratio 10

0 1 Prescaler ratio 8

1 0 Prescaler ratio 6

1 1 Prescaler ratio 4

0 0 Disable additional TV1, 2 offset

0 1 Enable additional TV1 offset +3.175V (for weather band)

1 0 Enable additional TV2 offset +3.175V (for weather band)

1 1 Enable additional TV1, 2 offset +3.175V (for weather band)

0 TV is tracking with PLL

1 TV is independing on PLL

Function

0 Normal AGC time constant

1 Short time constant for AM seek stop

0 Disable local mode

1 Enable local mode (PIN diode current = 0.5mA)

Table 20. Addr 8 quality ISS filter

MSB LSB

Function

d7 d6 d5 d4 d3 d2 d1 d0

0 ISS filter control “ON” recommended

1 ISS filter control “OFF”

0 Switch ISS filter “OFF”

1 Switch ISS filter “ON”

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TDA7540N Software specification

Table 20. Addr 8 quality ISS filter (continued)

MSB LSB

Function

d7 d6 d5 d4 d3 d2 d1 d0

0 Switch “OFF” ISS filter 120kHz

1 Switch “ON” ISS filter 80kHz

0 Switch “OFF” ISS filter 30KHz for weatherband

1 Switch “ON” ISS filter 30KHz for weatherband

000

001

010

011

discharge current1µA, charge current mid 74µA
narrow124µA

discharge current3µA, charge current mid 72µA
narrow122µA

discharge current5µA, charge current mid 70µA
narrow120µA

discharge current7µA, charge current mid 68µA
narrow118µA

--- -

111

discharge current15µA,charge current mid 60µA
narrow110µA

Table 21. Addr 9 quality detection adjacent channel

MSB LSB

d7 d6 d5 d4 d3 d2 d1 d0

0 dc-coupling deviation detector (has to be 0 in AM mode)

1 ac-coupling deviation detector (recommended mode)

0 AC highpass frequency 100kHz

1 AC bandpass frequency 100kHz

0 AC gain 32dB

1 AC gain 38dB

Function

0 0 0 AC wide band threshold 0.25V

0 0 1 AC wide band threshold 0.35V

0 1 0 AC wide band threshold 0.45V

--- -

1 1 1 AC wide band threshold 0.95V

0 0 AC narrow band threshold 0.0V

0 1 AC narrow band threshold 0.1V

1 0 AC narrow band threshold 0.2V

1 1 AC narrow band threshold 0.3V

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Software specification TDA7540N

Table 22. Addr 10 quality detection multipath

MSB LSB

Function

d7 d6 d5 d4 d3 d2 d1 d0

0 Multipath control “ON”

1 Multipath control “OFF”

0

1 MP bandpass frequency 31KHz

0 MP gain 12dB

1 MP gain 23dB

0 0 MP threshold 0.50V

0 1 MP threshold 0.75V

1 0 MP threshold 1.00V

1 1 MP threshold 1.25V

0 0 Application mode 1

0 1 Application mode 2

0 Multipath eliminates ac

1 Multipath eliminates ac and ac+

MP bandpass frequency 19KHz if MPION=1, NBSMP=1,
MPPC=1, than has to be 0

Table 23. Addr 11 quality deviation detection

MSB LSB

d7 d6 d5 d4 d3 d2 d1 d0

0 0 0 charge current 39µA

0 0 1 charge current 38µA

0 1 0 charge current 37µA

0 1 1 charge current 36µA

----

1 1 1 charge current 32µA, discharge current 8µA

0 0 DEV threshold for ISS narrow/wide 30kHz

0 1 DEV threshold for ISS narrow/wide 45kHz

1 0 DEV threshold for ISS narrow/wide 60kHz

1 1 DEV threshold for ISS narrow/wide 75kHz

0 0 DEV threshold for ISS filter “OFF” ratio 1.5

0 1 DEV threshold for ISS filter “OFF” ratio 1.4

1 0 DEV threshold for ISS filter “OFF” ratio 1.3

1 1 DEV threshold for ISS filter “OFF” ratio 1

Function

, discharge current 1µA

, discharge current 2µA

, discharge current 3µA

, discharge current 4µA

50/76

TDA7540N Software specification

Table 23. Addr 11 quality deviation detection

MSB LSB

Function

d7 d6 d5 d4 d3 d2 d1 d0

0

1

Disable ISS filter to fixed bandwith (ISS80) in automatic
control

Enable ISS filter to fixed bandwith (ISS80) in automatic
control

Table 24. Addr 12 softmute control 1

MSB LSB

Function

d7 d6 d5 d4 d3 d2 d1 d0

0 0 0 Startpoint mute 0 in application about 3dBµV antenna level

0 0 1 Startpoint mute 1 in application about 4dBµV antenna level

----

1 1 1 Startpoint mute 7 in application about 10dBµV antenna level

0000 Mute depth 0 in application 18dB

0001 Mute depth 1 in application 20dB

0010 Mute depth 2 in application 22dB

0011 Mute depth 3 in application 24dB

---- - (logarithmically behaviour)

1111 Mute depth 15 in application 36dB

0 FM mute disable, (has to be 0 in AM mode)

1 FM mute enable

Table 25. Addr 13 softmute control 2

MSB LSB

d7 d6 d5 d4 d3 d2 d1 d0

0 Disable mute threshold for ISS filter “ON”

1 Enable mute threshold for ISS filter “ON”

0 0 AC mute depth 10dB

0 1 AC mute depth 8dB

1 0 AC mute depth 6dB

1 1 AC mute depth 4dB

0000 AC mute threshold 60mV

0001 AC mute threshold 80mV

0010 AC mute threshold 100mV

---- -

0111 AC mute threshold 340mV

51/76

Function

Software specification TDA7540N

Table 25. Addr 13 softmute control 2

MSB LSB

Function

d7 d6 d5 d4 d3 d2 d1 d0

1111 AC mute “OFF”

0 AC mute filter 110KHz

1 AC mute filter 100KHz

Table 26. Addr 14 VCODIV/PLLREF

MSB LSB

Function

d7 d6 d5 d4 d3 d2 d1 d0

0 0 not valid (only for testing)

0 1 VCO frequency divided by 2

1 0 VCO frequency divided by 3

1 1 original VCO frequency

0 VCO” I” signal 0 degree

1 VCO “I” signal 180 degree

1 0 0 PLL reference frequency 50KHz

1 0 1 PLL reference frequency 25KHz

1 1 0 PLL reference frequency 10KHz

1 1 1 PLL reference frequency 9KHz

0 0 0 PLL reference frequency 2KHz

0 Select FM mode

1 Select AM mode

0 Select PLL low pass filter FM

1 Select PLL low pass filter AM

Table 27. Addr 15 FM AGC

MSB LSB

d7 d6 d5 d4 d3 d2 d1 d0

0 0 RFAGC threshold V

0 1 RFAGC threshold V

1 0 RFAGC threshold V

1 1 RFAGC threshold V

0 0 IFAGC threshold V

0 1 IFAGC threshold V

1 0 IFAGC threshold V

1 1 IFAGC threshold V

9-11TH

9-11TH

9-11TH

9-11TH

77TH

77TH

77TH

77TH

Function

= 85(77 ANT)dBµV

= 90(82 ANT)dBµV

= 94(86 ANT)dBµV

= 96(88 ANT)dBµV

= 86(60 ANT)dBµV

= 92(66 ANT)dBµV

= 96(70 ANT)dBµV

= 98(72 ANT)dBµV

52/76

TDA7540N Software specification

Table 27. Addr 15 FM AGC

MSB LSB

Function

d7 d6 d5 d4 d3 d2 d1 d0

0 0 0 KAGC threshold 80dBµV

0 0 1 KAGC threshold 82dBµV

0 1 0 KAGC threshold 84dBµV

0 1 1 KAGC threshold 86dBµV

1 0 0 KAGC threshold 88dBµV

1 0 1 KAGC threshold 90dBµV

1 1 0 KAGC threshold 92dBµV

111 Keying AGC “OFF”

0RF KAGC“0FF”

1RF KAGC“0N”

Table 28. Addr 16 AM AGC

MSB LSB

d7 d6 d5 d4 d3 d2 d1 d0

0000not valid

0001not valid

0010WAGC V

0011WAGC V

0100WAGC V

0101WAGC V

0110WAGC V

0111WAGC V

1000WAGC V

1001WAGC V

1010WAGC V

1011WAGC V

1100WAGC V

1101WAGC V

1110WAGC V

1111WAGC V

0000 DAGC V

0001 DAGC V

0010 DAGC V

0011 DAGC V

= 97dBµ V

4TH

= 98.5dBµ V

4TH

= 100dBµ V

4TH

= 101.5dBµ V

4TH

= 102.5dBµ V

4TH

= 103.5dBµ V

4TH

= 104.5dBµ V

4TH

= 105dBµ V

4TH

= 106dBµ V

4TH

= 106.5dBµ V

4TH

= 107dBµ V

4TH

= 108dBµ V

4TH

= 108.5dBµ V

4TH

= 109dBµ V

4TH

= 74dBµ

71TH

= 77dBµ

71TH

= 79dBµ

71TH

= 80.5dBµ

71TH

Function

= 96.5dBµ

71TH

71TH

71TH

71TH

71TH

71TH

71TH

71TH

71TH

71TH

71TH

71TH

71TH

71TH

= 98.5dBµ

= 100dBµ

= 101dBµ

= 102.5dBµ

= 103.5dBµ

= 104dBµ

= 105dBµ

= 105.5dBµ

= 106.5dBµ

= 107dBµ

= 107.5dBµ

= 108dBµ

= 108.5dBµ

53/76

Software specification TDA7540N

Table 28. Addr 16 AM AGC (continued)

MSB LSB

Function

d7 d6 d5 d4 d3 d2 d1 d0

0100 DAGC V

0101 DAGC V

0110 DAGC V

0111 DAGC V

1000 DAGC V

1001 DAGC V

1010 DAGC V

1011 DAGC V

1100 DAGC V

1101 DAGC V

1110 DAGC V

1111 DAGC V

Table 29. Addr 17 FM demodulator fine adjust

MSB LSB

d7 d6 d5 d4 d3 d2 d1 d0

0000000mV

000001+8.5mV

71TH

71TH

71TH

71TH

71TH

71TH

71TH

71TH

71TH

71TH

71TH

71TH

= 82dBµ

= 83.5dBµ

= 85dBµ

= 86.5dBµ

= 88dBµ

= 89dBµ

= 90dBµ

= 91dBµ

= 92dBµ

= 93dBµ

= 94dBµ

= 96dBµ

Function

000010+17mV

-------

011111+263.5mV

1000000mV

100001-8.5mV

100010-17mV

-------

111111-263.5mV

0 0 Spike cancelation ”OFF”

0 1 Threshold for spike cancelation 750mV

1 0 Threshold for spike cancelation 270mV

1 1 Threshold for spike cancelation 520mV recommended

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TDA7540N Software specification

Table 30. Addr 18 S-meter slider

MSB LSB

d7 d6 d5 d4 d3 d2 d1 d0

0000S meter slider offset SL=0dB

0001S meter offset SL=1dB

0010S meter offset SL=2dB

-----

1111S meter offset SL=15dB

0 S meter offset -SL

1 S meter offset +SL

0 S Meter slope 1V/decade

1 S meter slope 1.5V/decade

0 Overdeviation correction current max=45µA

1 Overdeviation correction current max=90µA

0 Overdeviation correction “OFF”

1 Overdeviation correction “ON”

Table 31. Addr 19 IF GAIN/XTAL adjust

Addr 20 Tank Adjust

Function

MSB LSB

d7 d6 d5 d4 d3 d2 d1 d0

0 Xtal amplitude limitation disable

1 Xtal amplitude limitation enable

0 0 IF1 gain1 9dB

0 1 IF1 gain1 12dB

1 0 IF1 gain1 15dB

1 1 IF1 gain1 18dB

00000 C

00001 C

00010 C

00011 C

00100 C

----- -

11111 C

Load

Load

Load

Load

Load

Load

Function

0pF

0.75pF

1.5pF

2.25pF

3pF

23.25pF

55/76

Software specification TDA7540N

Table 32. Tank adjust

MSB LSB

d7 d6 d5 d4 d3 d2 d1 d0

0 0 0 0 450kHz 0pF

0 0 0 1 450kHz 1.6pF

0 0 1 0 450kHz 3.2pF

0 0 1 1 450kHz 4.8pF

-----

1 1 1 1 450kHz 24pF

0 0 0 0 10.7MHz 0pF

0 0 0 1 10.7MHz 0.55pF

0 0 1 0 10.7MHz 1.1pF

0 0 1 1 10.7MHz 1.65pF

---- -

1 1 1 1 10.7MHz 8.25pF

Table 33. Addr 21 I/Q FM mixer1 adjust

Function

MSB LSB

Function

d7 d6 d5 d4 d3 d2 d1 d0

0000-7 degree

0001-6 degree

0010-5 degree

-----

01110 degree

1000+1 degree

1001+2 degree

-----

1111+8degree

0 0 Softmute reference offset OFF

0 1 Softmute reference offset -50mV

1 0 Softmute reference offset -100mV

1 1 Softmute reference offset -150mV

56/76

TDA7540N Software specification

Table 34. Addr 22 AM IF noise blanker

MSB LSB

d7 d6 d5 d4 d3 d2 d1 d0

0000Not valid

0001AINBT 12.5mV

0010AINBT 25mV

-----

1111AINBT 187.5mV

0 0 AINBD “ON”

0 1 AINBD 4.0V

1 0 AINBD 3.2V

1 1 AINBD “OFF”

00 AINT 8µs

0 1 AINT 11µs

1 0 AINT 14µs

1 1 AINT 17µs

Table 35. Addr 23 switch control

Function

MSB LSB

Function

d7 d6 d5 d4 d3 d2 d1 d0

0 S1 LOW output voltage

1 S1 HIGH output voltage

0 S1 emitter output available

1 S1 open collector output available

0 S2 LOW output voltage

1 S2 HIGH output voltage

0 S2 emitter output available

1 S2 open collector output available

0000 SSTOP=IFC (IF counter status)

0001 SSTOP= H if IFC=H&FSU>0.89V

0010 SSTOP= H if IFC=H&FSU>1.16V

0011 SSTOP= H if IFC=H&FSU>1.43V

----

1111 SSTOP= H if IFC=H&FSU>4.67V

57/76

Software specification TDA7540N

Table 36. Addr 24 stereodecoder 1

MSB LSB

Function

d7 d6 d5 d4 d3 d2 d1 d0

1 only for testing (has to be set to 1)

0 not valid (only for testing)

1 Audio AM noise blanker fix threshold enable

1 only for testing (has to be set to 1)

0 Audio inverter OFF

1 Audio inverter ON

0 0 Audio noise blanking time 38µs

0 1 Audio noise blanking time 25.5µs

1 0 Audio noise blanking time 32µs

1 1 Audio noise blanking time 22µs

0 Stereodecoder VCO adjust minus

1 Stereodecoder no VCO adjust recommended

0 Stereodecoder VCO adjust plus

1 Stereodecoder no VCO adjustrecommended

Table 37. Addr 25 stereodecoder 2

MSB LSB

d7 d6 d5 d4 d3 d2 d1 d0

0 Stereo decoder mute disable

1 Stereo decoder mute enable

0 Stereo decoder “ON” if muted

1 Stereo decoder “OFF” if muted

0 Forced MONO, must be set in AM

1 MONO/STEREO switch automatically

0 Noise blanker peak charge current low

1 Noise blanker peak charge current high

0 Pilot threshold high

1 Pilot threshold low

0 Deemphasis 50µs

1 Deemphasis 75µs

0 0 Stereodecoder ingain = 3.75dB

0 1 Stereodecoder ingain = 2.5dB

Function

1 0 Stereodecoder ingain = 1.25dB

1 1 Stereodecoder ingain = 0dB

58/76

TDA7540N Software specification

Table 38. Addr 26 stereodecoder 3

MSB LSB

d7 d6 d5 d4 d3 d2 d1 d0

0 0 0 Audio noise blanker low threshold 280mV

0 0 1 Audio noise blanker low threshold 261mV

0 1 0 Audio noise blanker low threshold 242mV

0 1 1 Audio noise blanker low threshold 223mV

1 0 0 Audio noise blanker low threshold 204mV

1 0 1 Audio noise blanker low threshold 185mV

1 1 0 Audio noise blanker low threshold 166mV

1 1 1 Audio noise blanker low threshold 147mV

0 0 Audio noise blanker noise controlled threshold 1200mV

0 1 Audio noise blanker noise controlled threshold 950mV

1 0 Audio noise blanker noise controlled threshold 700mV

1 1 Audio noise blanker noise controlled threshold 450mV

0 Audio noise blanker OFF

1 Audio noise blanker ON

Function

0 0 Deviation adjust 2.0V

0 1 Deviation adjust 1.5V

1 0 Deviation adjust 1.0V

1 1 Deviation detector off

Table 39. Addr 27 stereodecoder 4

MSB LSB

d7 d6 d5 d4 d3 d2 d1 d0

0 High Cut OFF

1 High Cut ON

0 0 max. High Cut 10dB

0 1 max. High Cut 5.5dB

1 0 max. High Cut 7.5dB

1 1 max. High Cut 8.5dB

0 0 Start level High Cut at 42% REF5V

0 1 Start level High Cut at 50% REF5V

1 0 Start level High Cut at 58% REF5V

1 1 Start level High Cut at 66% REF5V

Function

0 0 Stop level High Cut at 11% VHCH

0 1 Stop level High Cut at 18.3% VHCH

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Software specification TDA7540N

Table 39. Addr 27 stereodecoder 4 (continued)

MSB LSB

Function

d7 d6 d5 d4 d3 d2 d1 d0

1 0 Stop level High Cut at 25.7% VHCH

1 1 Stop level High Cut at 33% VHCH

0 Strong multipath influence on peak discharge OFF

1 Strong multipath influence on peak discharge ON (MPF = 0!!)

Table 40. Addr 28 stereodecoder 5

MSB LSB

d7 d6 d5 d4 d3 d2 d1 d0

0 0 0 Stereoblend control at 29% REF5V

0 0 1 Stereoblend control at 33% REF5V

0 1 0 Stereoblend control at 38% REF5V

0 1 1 Stereoblend control at 42% REF5V

1 0 0 Stereoblend control at 46% REF5V

1 0 1 Stereoblend control at 50% REF5V

1 1 0 Stereoblend control at 54% REF5V

1 1 1 Stereoblend control at 58% REF5V

0 0 Audio noise blanker field strength adjust 2.0V

0 1 Audio noise blanker field strength adjust 1.6V

1 0 Audio noise blanker field strength adjust 1.4V

1 1 Audio noise blanker field strength adjust OFF

0 0 Quality detector coefficient a=0.6

0 1 Quality detector coefficient a=0.75

1 0 Quality detector coefficient a=0.9

1 1 Quality detector coefficient a=1.05

Function

0 Multipath influence on peak discharge OFF

1

Table 41. Addr 29 stereodecoder 6

Multipath influence on peak discharge ON (-1V/ms) (MPF = 0!!)

MSB LSB

Function

d7 d6 d5 d4 d3 d2 d1 d0

0 0 Noise rectifier discharge resistor = infinite

0 1 Noise rectifier discharge resistor =56K

1 0 Noise rectifier discharge resistor =33K

1 1 Noise rectifier discharge resistor =18K

60/76

TDA7540N Software specification

Table 41. Addr 29 stereodecoder 6 (continued)

MSB LSB

Function

d7 d6 d5 d4 d3 d2 d1 d0

0 0 Multipath detector band pass gain =6dB

0 1 Multipath detector band pass gain =12dB

1 0 Multipath detector band pass gain =9dB

1 1 Multipath detector band pass gain =10.5dB

0 Multipath detector internal influence ON

1 Multipath detector internal influence OFF

0 Multipath detector charge current =0.8µA

1 Multipath detector charge current =0.4µA

0 0 Multipath detector rectifier gain =7.6dB

0 1 Multipath detector rectifier gain =4.6dB

1 0 Multipath detector rectifier gain =0dB

1 1 Multipath detector rectifier gain disabled

Table 42. Addr 30 stereodecoder 7

MSB LSB

d7 d6 d5 d4 d3 d2 d1 d0

0000Roll-Off compensation not allowed

0001Roll-Off compensation 17.1%

0010Roll-Off compensation 15.2%

0011Roll-Off compensation 13.3%

0100Roll-Off compensation 11.4%

0101Roll-Off compensation 9.6%

0110Roll-Off compensation 7.8% recommended

0111Roll-Off compensation 6.0%

1000Roll-Off compensation not allowed

1001Roll-Off compensation 4.7%

1010Roll-Off compensation 2.9%

1011Roll-Off compensation 1.3%

1100Roll-Off compensation -0.2%

1101Roll-Off compensation -1.8%

Function

1110Roll-Off compensation -3.4%

1111Roll-Off compensation -5%

0 0 0 Level gain 0dB

0 0 1 Level gain 0.67dB

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Software specification TDA7540N

Table 42. Addr 30 stereodecoder 7 (continued)

MSB LSB

Function

d7 d6 d5 d4 d3 d2 d1 d0

0 1 0 Level gain 1.34dB

--- -

1 1 1 Level gain 4.7dB

0 AM audio filter “OFF”

1 AM audio filter “ON” (has to be set if AMNB is used !!)

Table 43. Addr 31 stereodecoder 8

MSB LSB

Function

d7 d6 d5 d4 d3 d2 d1 d0

0 0 Quality noise gain =6dB

0 1 Quality noise gain =9dB

1 0 Quality noise gain =12dB

1 1 Quality noise gain =15dB

0 Enable AFS PIN

1 Disable AFS PIN

0 AFS influence on stereodecoder mute

1 No AFS influence on stereodecoder mute

0 PD hold activation if AFS<V

1 PD hold activation if AFS<V

th1

th2

0/1 not valid

0/1 not valid

0 AM audio delay for noise blanking “OFF”

1

Table 44. Addr 32 stereodecoder 9

AM audio delay for noise blanking “ON”(has to be set if
AMNB is used !!)

MSB LSB

Function

d7 d6 d5 d4 d3 d2 d1 d0

0 Deemphasis shift (25/37.5µs)

1 Deemphasis no shift (50/75µs)

00000 AM corner frequency = 3.18kHz

00001 AM corner frequency = 3.10kHz

00010 AM corner frequency = 3.02kHz

-----

11101 AM corner frequency = 1.12kHz

11111 AM corner frequency = 1.06kHz

62/76

TDA7540N Software specification

Table 45. Addr 33 test tuner control 1

MSB LSB

Function

d7 d6 d5 d4 d3 d2 d1 d0

xxxxxxxxOnly for testing ( have to be set to 0)

Table 46. Addr 34 test tuner control 2

MSB LSB

Function

d7 d6 d5 d4 d3 d2 d1 d0

xxxxxxxxOnly for testing ( have to be set to 0)

Table 47. Addr 35 test tuner control 3

MSB LSB

Function

d7 d6 d5 d4 d3 d2 d1 d0

xxxxxxxxOnly for testing ( have to be set to 0)

Table 48. Addr 36 test tuner control 4

MSB LSB

Function

d7 d6 d5 d4 d3 d2 d1 d0

xxxxxxxxOnly for testing ( have to be set to 0)

Table 49. Addr 37 test tuner control 5

MSB LSB

Function

d7 d6 d5 d4 d3 d2 d1 d0

xxxxxxxxOnly for testing ( have to be set to 0)

Table 50. Addr 38 test stereodecoder control

MSB LSB

Function

d7 d6 d5 d4 d3 d2 d1 d0

xxxxxxx0Only for testing ( have to be set to 1)

Table 51. Addr39 test FM demodulator spike blanker and stereo decoder

MSB LSB

Function

d7 d6 d5 d4 d3 d2 d1 d0

xxxxxxx0Only for testing ( have to be set to 1)

63/76

Appendix TDA7540N

6 Appendix

Figure 8. Block diagram I/Q mixer

Figure 9. Block diagram VCO

64/76

TDA7540N Appendix

Figure 10. Block diagram keying AGC

Figure 11. Block diagram ISS function

65/76

Appendix TDA7540N

Block diagram quality detection principle (without overdeviation correction)

Table 52. Block diagram quality detection principle

ac No adjacent channel Adjacent channel present

ac+ No strong adjacent channel Adjacent channel higher as ac

sm Fieldstrength higher as softmute threshold Fieldstrength lower as softmute threshold

dev Deviation lower as threshold DWTH Deviation higher as threshold DWTH

dev+ Deviation lower as threshold DTH*DWTH Deviation higher as threshold DTH*DWTH

inton ISS filter off by logic (wide) ISS filter on by logic

int80 ISS filter 120kHz (mid) ISS filter 80kHz (narrow)

Signal Low High

Table 53. Functional mode quality detection

Input signals Mode1 Mode2

ac ac+ sm dev dev+ inton int80 Function inton int80 Function

000000 0wide0 0wide

000100 0wide0 0wide

000110 0wide0 0wide

0 0 1 0 0 1 1 narrow 1 1 narrow

001100 0wide1 0mid

001110 0wide0 0wide

100001 1narrow1 0mid

1 1 0 0 0 1 1 narrow 1 1 narrow

100101 0mid1 0mid

110111 0mid1 1narrow

1 0 1 0 0 1 1 narrow 1 1 narrow

1 1 1 0 0 1 1 narrow 1 1 narrow

101101 0mid1 0mid

111101 0mid1 1narrow

101111 0mid1 0mid

111111 0mid1 1narrow

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TDA7540N Appendix

Figure 12. Block diagram AM part

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Appendix TDA7540N

Figure 13. Block diagram AM IF noise blanker

Figure 14. Block diagram stereodecoder

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TDA7540N Appendix

Figure 15. Block diagram audio noise blanker

Figure 16. Block diagram multipath detection

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Appendix TDA7540N

Figure 17. Block diagram AFS function

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TDA7540N Part list

7 Part list

Table 54. Part list (application- and measurment circuit)

Item Description

F1 TOKO 5KM 396INS-A543EK

F2 TOKO MC152 E558HNA-100092

F3 TOKO 7PSG P826RC-5134N

F4 TOKO PGL 5PGLC-5103N

L1 TOKO FSLM 2520-150 15uH

L2,L4 TOKO FSLM 2520-680 68uH

L3 SIEMENS SIMID03 B82432 1mH

L5 TOKO LLQ 2012-220

L6 TOKO LLQ 2012-680

CF1,CF2 muRata SFE10.7MS3A10-A 180KHz

CF3 muRata SFE10.7MJA10-A 150KHz

CF4 muRata SFPS 450H

D1 TOSHIBA 1SV172

D2,D3 TOKO KP2311E

D4 TOKO KV1410

D5 PHILIPS BB156

Q1 TOSHIBA HN3G01J

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Application circuit TDA7540N

8 Application circuit

Figure 18. Application circuit

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TDA7540N Application notes

9 Application notes

Following items are important to get highest performance of TDA7540N in application:

1. In order to avoid leakage current from PLL loop filter input to ground a guardring is

recommended around loop filter PIN’s with PLL reference (VREF2) voltage potential.

2. Distance between Xtal and VCO input PIN 18 should be far as possible and Xtal

package should get a shield versus ground.

3. Blocking of VCO supply should be near at PIN 20 and PIN 21.

4. Blocking of VCC2 supply should be near at PIN 64 and PIN 61.

5. Wire lenght to FM mixer1-input and -output should be symetrically and short.

6. FM demodulator capacitance at PIN 56 should be sense connected as short as

possible versus demodulator ground at PIN 57.

7. Wire lenght from AM mixer tank output to 9KHz ceramic filter input has to be short as

possible.

8. To minimize “AM TWEET” the AM demodulator capacitor should be connected versus

GNDVCC1 at PIN 41 and FSU output at PIN 22 should be filtered with capacitor of
about 2,2nF versus GNDVCC2.

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Package information TDA7540N

10 Package information

In order to meet environmental requirements, ST offers these devices in ECOPACK®
packages. These packages have a lead-free second level interconnect. The category of
second level interconnect is marked on the package and on the inner box label, in
compliance with JEDEC Standard JESD97. The maximum ratings related to soldering
conditions are also marked on the inner box label. ECOPACK is an ST trademark.
ECOPACK specifications are available at: www.st.com.

Figure 19. LQFP80 (14x14x1.40mm) mechanical data and package dimensions

DIM.

A 1.600 0.0630

A1 0.050 0.150 0.0020 0.0059

A2 1.350 1.400 1.450 0.0531 0.0551 0.0571

b 0.220 0.320 0.380 0.0087 0.0126 0.0150

c 0.090 0.200 0.0035 0.0079

D 15.800 16.000 16.200 0.6220 0.6299 0.6378

D1 13.800 14.000 14.200 0.5433 0.5512 0.5591

D3 12.350 0.4862

E 15.800 16.000 16.200 0.6220 0.6299 0.6378

E1 13.800 14.000 14.20 0 0.5433 0.5512 0.5591

E3 12.350 0.4862

e 0.650 0.0256

L 0.450 0.600 0.750 0.0177 0.0236 0.0295

L1 1.000 0.0394

k 0˚ (m in.); 3.5˚ (typ,); 7˚ (max.)

ccc 0.100 0.0039

mm inch

MIN. TYP. MAX. MIN. TYP. MAX.

OUTLINE AND

MECHANICAL DATA

LQFP80 (14x14x1.40mm)

Low profile Quad Flat Package

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0062342 D

TDA7540N Revision history

11 Revision history

Table 55. Document revision history

Date Revision Changes

12-Nov-2007 1 Initial release.

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TDA7540N

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