SGS Thomson Microelectronics TDA7421 Datasheet

®

FRONT-END FOR AM/FM RECEIVERS UP-CONVERSION ARCHITECTURE FOR AM HIGH SPEED PLL WITH INLOCK DETECTOR

FOR OPTIMIZED RDS APPLICATIONS SINGL E FR EQUE NCY REFE RENC E FO R AM/F M AM/FM STATION DETECTOR µP-CONTROLLED COMPENSATION OF EX-

TERNAL COMPONENTS SPREAD ADJUSTABLE AUDI O MUTE FULLY PROGRAMMABLE BY I2C BUS ADVANCED BICMOS TECHN OLOGY

TDA7421

AM/FM TUNER FOR CAR RADI O

AND Hi-Fi APPLICATIONS

TQFP64

ORDERING NUMBER:

TDA7421

GENERAL DESCRIPTION

The TDA7421 is a high performance tuner circuit that integrates AM/FM sections, IF counter and PLL synthesizer on a single chip.

Use of BICMOS technology allows the im plementation of tuning functions with a minimum of external components. Value spread of external components can be fully

PINS CONNECTION

FM IF AGC IN

AM MIX2 IN +

AM MIX2 IN-

MIX OUT -

MIX OUT +

AM AGC1 TC

AM AGC1 RF AMP

AM AGC1 PIN

60

61

62

63

AM MIX1 IN -

AM MIX1 IN +

FM MIX IN -

FM MIX IN +

FM RF AGC IN

FM AGC OUT

RF GND

VCO B VCO E

OSC GND

XTAL D XTAL G

OSC VCC

FM ANT ADJ

FM RF ADJ

PLL VCC

64 1 2 3 4 5 6 7 8 9 10

12 13 14 15 16

17 18 19 20 21

59 58 57 56 5455 53 52 51 50 49

22 23 24 25 26

compensated by means of on-chip electrical adjustment controlled by external µP.

The Automatic Gain Control (AGC) operates on different sensitivities and bandwidths in order to improve sensitivity and dynamic range. I allows to control selected functions of the tuner (AGC and amplifiers gain, PLL and counters operation modes).

RF VCC

AM MIX2 OUT -

AM MIX2 OUT +

FM IF AMP1 IN +

FM IF AMP1 IN -

FM IF AMP1 OUT

FM IF AMP2 IN +

FM IF AMP2 IN -

48

FM IF AMP2 OUT

47

IF1 VCC

46

FM LIM IN +

45

FM LIM IN -

44

IF1 GND

43

FM BW TC

42

FM MUTE DRIVE FM SMETER AM SMETER

41

FM DET ADJ

40

FM SD AM SD

39

AUDIO OUT

38

FM QUAD+

37

FM QUAD-

36

IF2 VCC

35

AM IF2 IN

34

AM REF

33

AM BPF

271128 29 30 31 32

2

C bus

June 1998

LP IN1

LP OUT

LP IN2

LP IN3

PLL GND

PLL VREF

SLEEP

SDA

SCL

DIG VDD

DIG GND

IF2 GND

CLN GND

STEREO OUT

IFC SSTOP AM

D96AU546A

AM DET

AM AGC2 TC

1/38

TDA7421

BLOCK DIAGRAM

AUDIO OUT

FM SMETER

AM SMETER

FM DET ADJ OUT

AM SD/

FM SD

BW TC

LPIN2

LPIN1

LPIN3

FM RF ADJ

FM ANT ADJ

LPOUT

PLL VCCPLL VREF

PLL GND

FM MUTE

QUAD-

QUAD+

IFC SSTOP

AM STEREO OUT

LIM IN+

LIM IN-

AMP2 OUT FM IF

AMP2 IN+ FM IF

AMP2 INFM IF

AMP1 OUT FM IF

AMP1 IN+ FM IF

AMP1 INFM IF

AGC IN FM IF

MIX OUT+

MIX OUT-

FILTER

ADJ.

AM IF

FM

AGC

FM AGC OUT

FM RF AGC IN

FM

DETECTOR

QUADRATURE

COUNT

ADJ.

FILTER

FM IF

AM

COUNTER

FM MIX

IN+

OUT

TRIPLE

SLIDER

AM

FM MIX

SMETER

LIMITER

IN-

FM SD

STOP

AM SD

STATION

MUTE

DETUNING

S METER

SOFT

DETECTOR

PHASE

COMPARATOR

÷

MUTE

VCOE

CH. MUTE

ADJACENT

CH. DET.

ADJACENT

OSC

10.25MHz

VCO

VCOB

XTALG

+

4 BIT DAC

AM IF

COUNTER

D96AU540A

÷

AM DET

+

4 BIT DAC

AGC

-

+

AM IF

AM

DETECTOR

AM AGC2

TC

AM

AM BPF

IFREF

-

PUMP

CHARGE

IN

DET

LOCK

ADJ.

AM RF AGC

AM MIX IN-

IN+

AM MIX

FILTER

AGC1 ANT

AM AGC1 RF AMP OUT

C

2

I

BUS

SCL

SDA

SLEEP

÷

XTALD

AM IF2

OUT+

AM MIX2

OUT-

AM MIX2

IN-

AM MIX2

MIX2 IN+

AM

AGCI TC

AM

2/38

ABSOLUTE MAXIMUM RATINGS

Symbol Parameter Value Unit

T

amb

T

stg

V

CC

V

DD

Operating Temperature Range -40 to 85 °C Storage Temperature Range -55 to 150 °C Analog Supply Voltages (PLL, RF, IF1, IF2, OSC) 10.2 V Digital Supply Voltage 5.5 V

THERMAL DATA

Symbol Parameter Value Unit

R

th j-amb

Thermal resistance Junction-Ambient typ. 68 °C/W

PIN DESCRIPTION

TDA7421

N. Name Function

1 AM MIX1 IN - Input "-" to the AM 1st mixer (differential input) 2 AM MIX1 IN + Input "+" to the AM 1st mixer (differential input) 3 FM MIX IN - Input "-" to the FM mixer (differential input) 4 FM MIX IN + Input "+" to the FM mixer (differential input) 5 FM RF AGC IN Input to the RF AGC circuit 6 FM AGC OUT Voltage output to the FM AGC 7 RF GND RF circuits ground 8 VCO B Local oscillator input to the transistor base (two-pin oscillator)

9 VCO E Local oscillator input to the transistor emitter (two-pin oscillator) 10 OSC GND Oscillator ground 11 XTAL D Crystal oscillator input to MOS drain (two-pin oscillator) 12 XTAL G Crystal oscillator input to MOS gate (two-pin oscillator) 13 OSC VCC Oscillator positive supply 14 FM ANT ADJ Tuning varicap voltage for antenna FM filter 15 FM RF ADJ Tuning varicap voltage for RF FM filter 16 PLL VCC PLL positive supply 17 LP OUT Op Amp output to PLL loop filters 18 LP IN1 PLL "N. 1" loop filter connection to Op Amp inverting input 19 LP IN2 PLL "N. 2" loop filter connection to Op Amp inverting input 20 LP IN3 PLL "N. 3" loop filter connection to Op Amp inverting input 21 PLL VREF Voltage reference to Op Amp noninverting input 22 PLL GND PLL ground

2

23 SLEEP I

C bus disconnect signal

24 SDA I2C bus data

2

25 SCL I

C bus clock

3/38

TDA7421

PIN DESCRIPTION

N. Name Function

27 DIG GND Digital circuits ground

28(*) IFC SSTOP

AM STEREO OUT 29 CLN GND "Clean" ground 30 IF2 GND IF 2nd ground 31 AM AGC2 TC AM 2nd AGC time constant 32 AM DET Connection to the capacitor of the AM diode-capacitor detector 33 AM BPF Connection to the AM IF filter 34 AM REF Reference voltage of AM IF amplifier 35 AM IF2 in Input (single ended) of AM 2nd IF amplifier 36 IF2 VCC IF 2nd positive supply 37 FM QUOD - "-" Insertion pt. of FM quadrature network (differential) 38 FM QUAD + "+" Insertion pt. of FM quadrature network (differential) 39 AUDIO OUT Audio frequency output (single ended)

40 (*) FM SD

41(*) FM SMETER

AM SMETER

FM DET ADJ 42 FM MUTE DRIVE FM mute time constant 43 FM BW TC FM detuning detector time constant 44 IF1 GND IF 1st ground 45 FM LIM IN - Input "-" of FM limiter (differential input) 46 FM LIM IN + Input "+" of FM limiter (differential input) 47 IF1 VCC IF 1st positive supply 48 FM IF AMP2 OUT Output (single ended) of the FM IF 2nd amplifier buffer 49 FM IF AMP2 IN - Input "-" of the FM IF 2nd amplifier (differential input) 50 FM IF AMP2 IN + Input "+" of the FM IF 2nd amplifier (differential input) 51 FM IF AMP1 OUT Output (single ended) of the FM IF 1st amplifier buffer 52 FM IF AMP1 IN - Input "-" of the FM IF 1st amplifier (differential input) 53 FM IF AMP1 IN + Input "+" of the FM IF 1st amplifier (differential input) 54 AM MIX2 OUT - Output "-" of the AM 2nd mixer (differential output) 55 AM MIX2 OUT + Output "+" of the AM 2nd mixer (differential output) 56 RF VCC RF stage positive supply 57 AM MIX2 IN - Input "-" to the AM 2nd mixer (differential input) 58 AM MIX2 IN + Input "+" to the AM 2nd mixer (differential input) 59 FM IF AGC IN Input FM IF AGC circuit 60 MIX OUT - Output "-" of the FM/AM 1st mixer (differential output) 61 MIX OUT + Output "+" of the FM/AM 1st mixer (differential output) 62 AM AGC1 TC AM 1st AGC time constant 63 AM AGC1 RF AMP Voltage output of the AM 1st AGC, to the transistor of the RF AF amplifier 64 AM AGC1 PIN Current output of the AM 1st AGC, to the PIN diodes antenna AM attenuator

(*) Pin function is user-defined by software.

AM SD

(continued)

Search stop signal or Output (single ended) of AM IF amplifier

FM Station detector output or AM Station detector output

FM S-meter output or AM S-meter output or FM detuning adjustment

4/38

TDA7421

ELECTRICAL CHARACTERISTICS DC PARAMETERS

amb

(T

= 25°C; Vcc = 8.5V, Vdd = 5V unless otherwise specified)

Symbol Parameter Test Condition Min. Typ. Max. Unit

DIG V

DIG I

Digital Supply Voltage 4.75 5.25 V

dd

Digital Supply Current AM MODE 4.0 4.6 5.2 mA

dd

FM MODE 3.5 4.0 4.5 mA

PLL V

PLL I

PLL Supply Voltage 7.5 10 V

CC

PLL Supply Current AM MODE 1.2 1.6 2.0 mA

CC

FM MODE 2.5 3.0 3.5 mA

RF V

RF I

RFSupply Voltage 7.5 10 V

CC

RF Supply Current AM MODE 15.0 17.5 20.0 mA

CC

FM MODE 10.0 13.0 16.0 mA

IF1 V

IF1 I

IF1 Supply Voltage 7.5 10 V

CC

IF1 Supply Current AM MODE 2.2 2.7 3.2 mA

CC

FM MODE 16.0 19.5 23.0 mA

IF2 V

IF2 I

IF2 Supply Voltage 7.5 10 V

CC

IF2 Supply Current AM MODE 8.5 10.5 12.5 mA

CC

FM MODE 27.0 32.0 37.0 mA

OSC V

OSC I

Oscillator Supply Voltage 7.5 10 V

CC

Oscillator Supply Current AM MODE 14.5 17.0 19.5 mA

CC

FM MODE 11.0 14.0 17.0 mA

TOTAL I

Total Supply Current AM MODE 45.0 50.0 55.0 mA

CC

FM MODE 73.0 81.0 89.0 mA

AC PARAMETERS

osc

Ref: FM Test Circuit measure V

with high impedance FET probe

Voltage Controlled Oscillator (VCO)

Symbol Parameter Test Condition Min. Typ. Max. Uni

f

VCOmin

f

VCOmax

V

OSC

Minimum VCO Frequency V

Maximum VCO Frequency V

Oscillator Amplitude fosc = 108.8MHz, Europe/USA

= 0, Europe/USA

turn

Japan

= VCC, Europe/USA

turn

Japan

f

= 72.3MHz, Japan

OSC

123.2

79.2

80.95598.2

65.4

128

90

106 dBu

Reference Oscillator

XTAL

Ref: AM Test Circuit measure V

Symbol Parameter Test Condition Min. Typ. Max. Uni

f

V

XTAL

Reference Frequency 10.25 MHz Oscillator Amplitude 108 dBu

with high impedance FET probe

MHz MHz

5/38

TDA7421

ELECTRICAL CHARACTERISTICS

(continued)

FM Section Global Performances

Refer to Evaluation Circuit and enclosed curves (S+N/N, THD)

- RF Input: f

= 98.1MHz, 75KHz dev., 1KHz mod.,60dBu

c

- Audio Output: BPF 20Hz - 20KHz

Symbol Parameter Test Condition Min. Typ. Max. Uni

S+N/N Signal to Noise Ratio 68 dB

THD Total Harmonic Distortion deviation = 40KHz 0.3 %

V

O AF

US Usable Sensitivity antenna level at which

Audio Output Level 350 400 450 mV

4dBu

S+N/N=30dB

AGC

range

Range AGC FM 65 dB

FM Front-e nd E le ctr ic al Ad jus tm en t s

Ref: FM Test Circuit measure V

ANTADJ

Symbol Parameter Test Condition Min. Typ. Max. Uni

ANTADJ

MAX OFF

ANTADJ

STEP OFF

RFADJ

MAX OFF

RFADJ

STEP OFF

Maximum FM Antenna Filter Adjustment Voltage Offset

FM Antenna Filter Adjustment Voltage Offset Step

Maximum FM RF Filter Adjustment Voltage Offset

FM RF Filter Adjustment Voltage Offset Step

and V

RFADJ

referred to V

V

PLLOUT

1111 V

PLLOUT

1001 V

PLLOUT

1111 V

PLLOUT

1001

PLLOUT

= 2.5V, ANA3-0 set to

= 2.5V, RFA3-0 set to

21 25 27 %

2.8 3.6 4.4 %

21 25 27 %

2.8 3.6 4.4 %

RMS

FM Mixer

Ref: FM Test Circuit, measure input at V

MIXFMIN

, output at V

Symbol Parameter Test Condition Min. Typ. Max. Unit

Z

IN,MIX

Single-ended input impedance

f = 100MHz 12 Ω

(pin 3, pin4)

G

IP3

CP1

MIX

Conversion Gain fIN = 98.1MHz 21.8 dB 3rd order intermodulation

distortion intercept point 1dB compression point fIN = 98.1MHz 90 dBu

MIX

fd = 98.1MHz; fu1 = 98.2MHz; f

= 98.3MHz;

u2

MIXOUT

104 dBu

FM AGC

Ref: FM Test Circuit, measure input at V

FMRFAGCIN

, and V

Symbol Parameter Test Condition Min. Typ. Max. Unit

V

RFAGCSTART

R

INRFAGC

V

IFAGCSTART

Open Loop Rf Agc Starting Point f

RFAGCIN

V

FMRFAGCIN

V

FMAGCOUT

Input Resistance 20 KΩ Open Loop If Agc Starting Point f

IFAGCIN

V

FMIFAGCIN

V

FMAGCOUT

FAGC2-0 set to 111

R

INIFAGC

R

OUTFMAGC

Input Resistance 20 KΩ Output Resistance 10 KΩ

FMIFAGCIN

, output at V

= 98.1MHz Value of

, at which

= 4V

= 10.7MHz Value of

, at which

= 4V

FMAGCOUT

74 80 86 dBu

71 77 83 dBu

6/38

TDA742 1

ELECTRICAL CHARACTERISTICS FM IF Amplifier 1

Ref: FM Test Circuit, measure input at V

(continued)

FMAMP1IN

, output at V

FMAMP1OUT

Symbol Parameter Test Condition Min. Typ. Max. Unit

R

IN,AMP1

R

OUT,AMP1

G

TYP,AMP1

Input Resistance f = 10.7MHz 330 Ω Output Resistance f = 10.7MHz 330 Ω Typical Gain fIN = 10.7MHz, FBH3-0 set to

16.5 17.5 18.5 dB

0100

G

MIN,AMP1

Minimum Gain fIN = 10.7MHz, FBH3-0 set to

14.5 15.5 16.5 dB

0001

G

MAX,AMP1

Maximum Gain fIN = 10.7MHz, FBH3-0 set to

18.5 19.5 20.5 dB

0000

IP3

CP1

AMP1

3rd Order Intermodulation Distortion Intercept Point

1dB Compression Point fIN = 10.7MHz; FBH3-0 set to

fd = 10.7MHz; fu1= 10.8MHz; fu2=

10.9MHz, FBH3-0 set to 0100

109 dBu

96 dBu

0100

FM IF Amplifier 2

Ref: FM Test Circuit, measure input at V

FMAMP2IN

, output at V

Symbol Parameter Test Condition Min. Typ. Max. Unit

R

IN,AMP2

R

OUT,AMP2

G

TYP,AMP2

G

MIN,AMP2

G

MAX,AMP2

IP3

CP1

AMP2

Input Resistance f = 10.7MHz 330 Ω Output Resistance f = 10.7MHz 330 Ω Typical Gain fIN = 10.7MHz, FBL3-0 set to 0100 5 6 7 dB Minimum Gain fIN = 10.7MHz, FBL3-0 set to 0001 3 4 5 dB Maximum Gain fIN = 10.7MHz, FBL3-0 set to 0000 7 8 9 dB 3rd Order Intermodulation

Distortion Intercept Point

fd = 10.7MHz; fu1= 10.8MHz; fu2=

10.9MHz, FBL3-0 set to 0100

1dB Compression Point fIN = 10.7MHz; FBL3-0 set to 0100 110 dBu

FMAMP2OUT

122 dBu

FM Limiter, Field Strengh Meter and Demodulator

Ref: FM Test circuit, measure:

- Input at V

FMLIMIN

- filtered FS Meter output at V

- shifted FS Meter output at V

- demodulator adjustment output at V

Symbol Parameter Test Condition Min. Typ. Max. Unit

R

IN,LIM

G

LIM

LS Limiting Sensitivity 23 dBu SM1 Smeter 1 at V SM2 Smeter 2 at V SM3 Smeter 3 at V

SM

MINSHIFT

SM

MAXSHIFT

G

DEM

G

DEMADJ

NOTE1: Refer to Global application circuit; input at first Ceramic Filter in, FBH3-0 set to 0001, FBL3-0 set to 0001

, fIN = 10.7MHz

SM,FILT SM,SHIFT

Limiter Input Resistance 330 Ω Limiter Gain 90 dB

SM,FILT SM,FILT SM,FILT

Smeter Minimum Shift Voltage at V

SM,SHIFT

referred to V

Smeter Maximum Shift Voltage at V

SM,SHIFT

referred to V

Demodulator Conversion Gain V Demodulator Adjustment

Conversion Gain

(FMADJ set to 0)

SM,SHIFT

SM,FILT

(FMADJ set to 1)

V V V V

00000 V

11111

V V

= 42dBu 0.1

FMLIMIN

= 77dBu 2.4

FMLIMIN

= 102dBu 4.0

FMLIMIN

= 70dBu, FSL4-0 set to

FMLIMIN

= 70dBu, FSL4-0 set to

FMLIMIN

> LS 2 mV

FMLIMIN

> LS, measured at

FMLIMIN

, FMADJ set to 1

SMSHIFT

(1)

0.25 0.5

(1)

2.75 3.1

(1)

4.35 4.7

0.25 0.3 0.35 V

1.55 1.8 2.05 V

14 mV

(1) (1) (1)

V V V

RMS

KHz

RMS

KHz

7/38

/ /

TDA7421

ELECTRICAL CHARACTERISTICS

(continued)

FM Audio Amplifier

Ref: FM Test circuit, measure:

- Input at V

FMLIMIN

- audio output at V

- muting voltage at V

Symbol Parameter Test Condition Min. Typ. Max. Unit

V

MUTE

V

PLAY

G

AMP,PLAY

G

AMP,MUTE MAX

G

AMP,MUTE MIN

V

AF

THD AFTotal Harmonic distortion f

S+N/N AF Signal to Noise Ratio f

AMR Amplitude Modulation Rejection AM modulation deph 30%, f

AUDIO

curr

MUTE R

NOTE1: Refer to Global application circuit; input at first Ceramic Filter in, FBH3-0 set to 0001, FBL3-0 set to 0001

out

, = 95dBu, fIN = 10.7MHz

AUDIO

, BPF 20Hz to 20KHz

MUTE , DRIVE

Mute Voltage V

MUTE,DRIVE

29dB, FMHIGH set to 0, AUM2-0 set to 111

Play Voltage V

MUTE,DRIVE

1dB, FMHIGH set to 0, AUM2-0 set to 111

Audio Amplifier Gain in Play

V

MUTE,DRIVE

Conditions Audio Amplifier Highest Gain in

Mute Condition Audio Amplifier Lowest Gain in

Mute Condition AF Output Level f

V

MUTE,DRIVE

set to 1, AUM2-0 set to 001 V

MUTE,DRIVE

set to 0, AUM2-0 set to 111

DEV

V

MUTE,DRIVE

DEV

V

MUTE,DRIVE

DEV

V

MUTE,DRIVE

1KHz, with respect to FM modulated signal with f

40KHz, V Audio Out Current Capability 5 mA Mute Drive Output Resistance 1 KΩ

for which ∆VAF = -

< V > V > V

= 75KHz, F

< V

= 75KHz, F

< V

= 75KHz, F

< V

MUTE,DRIVE

PLAY

MUTE

MOD

MUTE

MOD

MUTE

MOD

MUTE

, FMHIGH

, FMHIGH = 1KHz,

= 1KHz, = 1KHz,

=

DEV

< V

MUTE

MOD

2V

0.3 V

9dB

6.5 dB

-21 dB

350

(1)

400 450

(1)

0.5 %

(1)

68

=

60

75 %

(1)

67 dB

mV

RMS

FM QUALITY DETECTORS Field Strength Detector

Ref: FM Test Circuit, measure:

- Input at V

FMLIMIN

- output at V

Symbol Parameter Test Condition Min. Typ. Max. Unit

FSD

MIN

FSD

MAX

8/38

, fIN = 10.7MHz, CW

MUTE,DRIVE

Field Strenght Detector Minimum Threshold

Field Strenght Detector Maximum V

V

FMLIMIN

V

MUTE,DRIVE

to 0000

FMLIMIN

V

MUTE,DRIVE

to 1111

level at which

= V

, FSM3-0 set

MUTE

level at which

= V

, FSM3-0 set

MUTE

40 dBu

60 dBu

TDA7421

ELECTRICAL CHARACTERISTICS

(continued)

Detuning Detector

Ref: FM Test Circuit, measure:

- Inputs at V

FMLIMIN

- output at V

Symbol Parameter Test Condition Min. Typ. Max. Unit

DD

START

DD

SLOPE,MIN

DD

SLOPE,MAX

DD

TRC

, CW

MUTE,DRIVE

Detuning Detector Starting Point frequency shift from 10.7MHz at Detuning Detector Minimum

Muting Slope

Detuning Detector Maximum Muting Slope

Detuning Detector Time Constant Ratio

which V

MUTE,DRIVE

= V

PLAY

frequency shift from 10.7MHz + DD V

at which V

START,

BWM2-0 set to 100,

MUTE,

MUTE,DRIVE

FMRECSEEK set to 0 frequency shift from 10.7MHz +

DD V

at which V

START,

BWM2-0 set to 001,

MUTE,

MUTE,DRIVE

FMRECSEEK set to 0 ratio of "reception" mode

integration time constant inside the Detuning Detector with respect to "seek" mode

±23 KHz

22.5 30 37.5 KHz

=

7.5 10 12.5 KHz

=

34/6 s/s

Adjacent Channel Detector

Ref: FM Test Circuit, measure:

- Inputs at V

- output at V

FMLIMIN

: desired 10.7MHz, 95dBu CW; undesired 10.8MHz CW

MUTE,DRIVE

- BWM2-0 set to 001

Symbol Parameter Test Condition Min. Typ. Max. Unit

ACD

MAX

Adjacent Channel Quality Detector Maximum Sensitivity Threshold

amplitude of undesired signal at which V

MUTE,DRIVE

= V

MUTE

,

91 dBu

HDM4-0 set to 11111

ACD

Adjacent Channel Quality Detector

MIN

Minimum Sensitivity Threshold

amplitude of undesired signal at which V

MUTE,DRIVE

= V

MUTE

,

94.8 dBu

HDM4-0 set to 00000

Field Strength Station Detector

Ref: FM Test Circuit, measure:

- Inputs at V

- output at V

FMLIMIN

: desired 10.7MHz, CW

FMSD

- FMRECSEEK set to 1

Symbol Parameter Test Condition Min. Typ. Max. Unit

FSSD

Field Strength Station Detector

MIN

Minimum Threshold Field Strength Station Detector

MAX

Maximum Threshold

V V

level at which

FMLIMIN

= 2.5, FSM4-0 set to 00000

FMSD

level at which

FMLIMIN

= 2.5, FSM4-0 set to 11111

FMSD

24 dBu 76 dBu

Detuning Sta tion Detector

Ref: FM Test Circuit, measure:

- Input at V

- output at V

FMLIMIN

FMSD

, CW;

- FMRECSEEK set to 1

Symbol Parameter Test Condition Min. Typ. Max. Unit

DSD Detuning Station Detector

Threshold

frequency shift from 10.7MHz at which V

FMSD

= 2.5V

23 KHz

9/38

TDA7421

ELECTRICAL CHARACTERISTICS

(continued)

Adjacent Channel Station Detector

Ref: FM Test Circuit, measure:

- Input at V

- output at V

FMLIMIN

: desired 10.7MHz, 95dBu CW; undesired 10.8MHz CW

FMSD

- FMRECSEEK set to 1

Symbol Parameter Test Condition Min. Typ. Max. Unit

ACSD

Adjacent Channel Detector

MAX

Maximum Sensitivity Threshold

amplitude of undesired signal at which V

= 2.5V, HDM4-0 set

FMSD

92.5 dBu

to 11111

ACD

Adjacent Channel Detector

MIN

Minimum Sensitivity Threshold

amplitude of undesired signal at which V

= 2.5V, HDM4-0 set

FMSD

94.9 dBu

to 00000

AM Section Global Performances

Refer to E v aluatio n Circui t a nd enclosed curves ( S +N /N, TH D)

- RF Input: f

c

= 1MHz, f

mod

= 1KHz, m = 0.3;

- Audio Output: BPF 20Hz - 20KHz

Symbol Parameter Test Condition Min. Typ. Max. Unit

V

IN MIN

V

∆V

IN US

Maximum Sensitivity V Usable Sensitivity S+N/N = 20dB 31 dBu AGC Range V

is

S+N/N Signal to Noise Ratio V

α

IMAG

α

Tw

Image Rejection f1 = 1.9MHz

Tweet V

THD Total Harmonic Distortion V

V

AF

AMST

Audio Output Level V AM IF2 Output level V

= 74dBu; ∆VAF = - 20dB 20 dBu

INRF

= 74dBu; ∆VAF = -10dB 50 dB

INRF

= 74dBu 46.0 53.0 dB

INRF

f

= 22.4MHz

2

= 74dBu; f1 = 900KHz;

INRF

1.2 dB

f2 = 1350KHz

= 74dBu; m = 0.3 0.45 1.0 %

INRF

V

= 74dBu; m = 0.8 1.73 %

INRF

V

= 120dBu; m = 0.3 0.33 %

INRF

= 74dBu 137 167 197 mV

INRF

= 74dBu 106 dBu

INRF

dB

RMS

AM Mixer 1

Ref: AM Test Circuit, measure input at V

MIX2AMIN

, output at V

Symbol Parameter Test Condition Min. Typ. Max. Unit

R

INMIX1

G

IP3

CP1

MIX1

Input Resistance 1.2 KΩ Conversion Gain fIN = 1MHz 7.5 8.5 9.5 dB 3rd Order Intermodulation

Distortion Intercept Point

fd = 1MHz; fu1 = 1.1MHz; f

= 1.2MHz;

u2

1dB Compression Point fIN = 1MHz 98.7 dBu

10/38

MIXOUT

115 dBu

TDA7421

ELECTRICAL CHARACTERISTICS

(continued)

AM Wide & Narrow AGC

Ref: AM Test Circuit, input at V

MIX1AMIN

, and V

Symbol Parameter Test Condition Min. Typ. Max. Unit

V

WAGCTYP

Open Loop WIDE AGC Typical Starting Point

V

WAGCMIN

Open Loop WIDE AGC Minimum Starting Point

V

WAGCMAX

Open Loop WIDE AGC Maximum Starting Point

V

NAGCTYP

Open Loop NARROW AGC Typical Starting Point

V

NAGCMIN

Open Loop NARROW AGC Minimum Starting Point

V

NAGCMAX

Open Loop NARROW AGC Maximum Starting Point

R

OUTAMAGC1

I

AMAGC1PIN

Output Resistance 23.3 KΩ Maximum Pin-diode Current f

MIX2AMIN,

f

WAGCIN

1000; V V

AMAGC1AMP

f

WAGCIN

0000; V V

AMAGC1AMP

f

WAGCIN

1111; V V

AMAGC1AMP

f

NAGCIN

to 1000; V V

AMAGC1AMP

f

NAGCIN

to 0000; V V

AMAGC1AMP

f

NAGCIN

to 1111; V V

AMAGC1AMP

WAGCIN

V

MIX1AMIN

output at V

= 1MHz, AAG3-0 set to

= 10.7MHz, AAG3-0 set

= 1MHz;

at which

MIX1AMIN

= 2.5V

at which

MIX1AMIN

= 2.5V

at which

MIX1AMIN

= 2.5V

MIX2AMIN

= 2.5V

MIX2AMIN

= 2.5V

MIX2AMIN

= 2.5V

= 90dBu; AAG3-0 set to

0000

at which

AMAGC1AMP

AMAGC1PIN

, andV

91.3 dBu

80.6 dBu

95.6 dBu

93.2 dBu

82.8 dBu

97.4 dBu

1.4 mA

AM Mixer 2

Ref: AM Test Circuit, m easure input at V

MIX2AMIN

, output at V

MIX2OUT

, (switches must be in position 2 for

AGC measurements).

Symbol Parameter Test Condition Min. Typ. Max. Unit

R

G

IP3

CP1

AGC

INMIX2

MIX2

MIXCP

MIXSP

MIXR

Input Resistance 5 KΩ Maximum conversion Gain fIN = 10.7MHz 19.6 dB 3rd Order Intermodulation

Distortion Intercept Point

fd = 10.7MHz; fu1 = 10.8MHz; f

= 10.9MHz;

u2

122 dBu

1dB Compression Point fIN = 10.7MHz 90.7 dBu Central Point of AGC2 Intevention

on Mixer 2

AGC2 Starting Point on Mixer 2 fIN = 10.7MHz; Value of V

fIN = 10.7MHz; V Value of V

for which V

MIX2AMIN

= 52dBu;

MIX2OUT

is AGC

MIX2AMIN

-

MIXCP

61.2 dBu

40 dBu

3dB

AGC2 Range on Mixer 2 fIN = 10.7MHz; Range of

V AGC

MIX2AMIN

MIXCP

for which V

±3dB

MIX2OUT

is

24 dB

11/38

TDA7421

ELECTRICAL CHARACTERISTICS

(continued)

AM IF2 Amplifier

Ref: AM Test Circuit, measure input at V

IN

= 450KHz.

f

IP2AMPIN

, output at V

Symbol Parameter Test Condition Min. Typ. Max. Unit

R

IN,IF2AMP

G

IF2AMP

AGC AGC

AGC

AMPCP

AMPSP

AMPR

Input Resistance 2 KΩ Maximum Gain V Central Point of AGC2 Intevention

on IF2 Amp

V V

AGC2 Starting Point on IF2 Amp Value of V

V

= 10dBu 51 dB

IF2AMPIN

= 72dBu; Value of

IF2AMPIN

IF2AMPOUT

IF2AMPIN

AGC2 Range on IF2 Amp fIN = 10.7MHz; Range of

V AGC

AGC2 Time Constant Ratio Ratio of AGC2 "reception" Time

TCR

MIX2AMIN

MIXCP

= for which V

±3dB

Constant and "seek" Time Constant

IF

AMST

AM IF2 Output Level at pin 28 V

IF2AMPIN

= 72dBu;

AMSTEREO set to 1

IF

AMSTcurr

Current Capability of pin 28 AMSTEREO set to 1 150 µA

is AGC

IP2AMPOUT

for which

- 3dB

AMPCP

MIX2OUT

, (switches must be in position 1),

115 dBu

63 dBu

36 dB

is

150/5 s/s

104 106 108 dBu

AM Field Strength Meter and Field Strength Station Detector

Ref: AM Test Circuit, measure at V

IN

= 10.7KHz.

- f

MIX2AMIN

, outputs at V

AMSMETER

and at V

AMSD

(switches in position 2),

- AMSEE K set to 1

Symbol Parameter Test Condition Min. Typ. Max Unit

AMSM1 AM Smeter 1 at V AMSM2 AM Smeter 2 at V AMSM3 AM Smeter 3 at V

AMSD

Station Detector Minimum

MIN

Threshold

AMSD

Station Detector Maximum

MAX

Threshold

AMSMETER AMSMETER AMSMETER

V V V

V ASS3-0 set to 0000

V ASS3-0 set to 1111

= 35dBu 2.2 2.89 3.6 V

MIX2AMIN

= 65dBu 2.5 3.26 4.0 V

MIX2AMIN

= 95dBu 3.0 3.73 4.5 V

MIX2AMIN MIX2AMIN

MIX2AMIN

at which V

AMSD

= 2.5V,

44 dBu

64 dBu

IF Counter Output

Ref: AM & FM Test Circuit, measure at pin 28

Symbol Parameter Test Condition Min. Typ. Max Unit

IFC

12/38

IFC

FM

AM

current

FM IFC Sensitivity V

FMRECSEEK set to 1, EW2-0 set to 101, IFS2-0 set to 010

AM IFC Sensitivity V

AMSEEK set to 1, EW2-0 set to 011, IF2-0 set to 100, AMFM STBY1-0 set to 10

IFC Current Capability 150 µA

at which Vpin 28 = 2.5V,

FMLIMIN

at which Vpin 28 = 2.5V,

IF2AMPIN

34 dBu

29 dBu