Philips TDA1072AT Datasheet

INTEGRATED CIRCUITS

DATA SH EET

TDA1072AT

AM receiver circuit

Product specification
File under Integrated Circuits, IC01

March 1989

Philips Semiconductors Product specification

AM receiver circuit TDA1072AT

GENERAL DESCRIPTION

The TDA 1072AT integrated AM receiver circuit performs the active and part of the filtering functions of an AM radio
receiver. It is intended for use in mains-fed home receivers and car radios. The circuit can be used for oscillator
frequencies up to 50 MHz and can handle RF signals up to 500 mV. RF radiation and sensitivity to interference are
minimized by an almost symmetrical design. The voltage-controlled oscillator provides signals with extremely low
distortion and high spectral purity over the whole frequency range even when tuning with variable capacitance diodes.
If required, band switching diodes can easily be applied. Selectivity is obtained using a block filter before the IF amplifier.

Features

• Inputs protected against damage by static discharge

• Gain-controlled RF stage

• Double balanced mixer

• Separately buffered, voltage-controlled and temperature-compensated oscillator, designed for simple coils

• Gain-controlled IF stage with wide AGC range

• Full-wave, balanced envelope detector

• Internal generation of AGC voltage with possibility of second-order filtering

• Buffered field strength indicator driver with short-circuit protection

• AF preamplifier with possibilities for simple AF filtering

• Electronic standby switch.

QUICK REFERENCE DATA

PARAMETER CONDITIONS SYMBOL MIN. TYP. MAX. UNIT

Supply voltage range V
Supply current range I
RF input voltage for

S+N/N = 6 dB at m = 30% V

RF input voltage for 3%

total harmonic distortion
(THD) at m = 80% V

AF output voltage with

= 2 mV; fI = 1 MHz;

V

I

m = 30% and f

AGC range: change of V

for 1 dB change of V

= 400 Hz V

m

I

O(AF)

Field strength indicator

voltage at V

= 2.7 kΩ V

R

L(9)

= 500 mV;

I

PACKAGE OUTLINE

P

P

I

I

O(AF)

IND

7.5 − 10 V
15 − 26 mA

− 1.5 −µV

− 500 − mV

− 310 − mV

− 86 − dB

− 2.8 − V

16-lead mini-pack; plastic (SO16; SOT109A); SOT109-1; 1996 August 13.

March 1989 2

Philips Semiconductors Product specification

AM receiver circuit TDA1072AT

(1) Coil data: TOKO sample no. 7XNS-A7523DY; L1: N1/N2 = 12/32; Qo = 65; QB = 57.

Filter data: Z

= 700 Ωat R

F

= 3 kΩ; Z1 = 4.8 kΩ.

3-4

Fig.1 Block diagram and test circuit (connections shown in broken lines are not part of the test circuit).

March 1989 3

Philips Semiconductors Product specification

AM receiver circuit TDA1072AT

FUNCTIONAL DESCRIPTION
Gain-controlled RF stage and mixer

The differential amplifier in the RF stage employs an AGC negative feedback network to provide a wide dynamic range.
Very good cross-modulation behaviour is achieved by AGC delays at the various signal stages. Large signals are
handled with low distortion and the S/N ratio of small signals is also improved. Low noise working is achieved in the
differential amplifier by using transistors with a low base resistance.

A double balanced mixer provides the IF output to pin 1.

Oscillator

The differential amplifier oscillator is temperature compensated and is suitable for simple coil connection. The oscillator
is voltage-controlled and has little distortion or spurious radiation. It is specially suitable for electronic tuning using
variable capacitance diodes. Band switching diodes can easily be applied using the stabilized voltage V
buffered oscillator output is available for driving a synthesizer. If this is not needed, resistor R

can be omitted.

L(10)

Gain-controlled IF amplifier

This amplifier comprises two cascaded, variable-gain differential amplifier stages coupled by a band-pass filter. Both
stages are gain-controlled by the AGC negative feedback network.

11-16

. An extra

Detector

The full-wave, balanced envelope detector has very low distortion over a wide dynamic range. The residual IF carrier is
blocked from the signal path by an internal low-pass filter.

AF preamplifier

This stage preamplifies the audio frequency output. The amplifier output stage uses an emitter follower with a series
resistor which, together with an external capacitor, provides the required low-pass filtering for AF signals.

AGC amplifier

The AGC amplifier provides a control voltage which is proportional to the carrier amplitude. Second-order filtering of the
AGC voltage achieves signals with very little distortion, even at low audio frequencies. This method of filtering also gives
a fast AGC settling time which is advantageous for electronic search tuning. The AGC settling time can be further
reduced by using capacitors of smaller value in the external filter. The AGC voltage is fed to the RF and IF stages via
suitable AGC delays. The capacitor at pin 7 can be omitted for low-cost applications.

Field strength indicator output

A buffered voltage source provides a high-level field strength output signal which has good linearity for logarithmic input
signals over the whole dynamic range. If field strength information is not needed, R

can be omitted.

L(9)

Standby switch

This switch is primariIy intended for AM/FM band switching. During standby mode the oscillator, mixer and demodulator
are switched off.

Short-circuit protection

All pins have short-circuit protection to ground.

March 1989 4

Philips Semiconductors Product specification

AM receiver circuit TDA1072AT

RATINGS

Limiting values in accordance with the Absolute Maximum Rating System (IEC 134)

PARAMETER CONDITIONS SYMBOL MIN. MAX. UNIT

Supply voltage V

P

= V

13-16

Input voltage

pins 14-15 V
pins 14-16 V
pins 15-16 V
pins 14-16 V
pins 15-16 V

Input current

(pins 14 and 15) I
Total power dissipation (note 1) P
Operating ambient temperature range T
Storage temperature range T
Junction temperature T

V

13

14-15
14-16
15-16
14-16
15-16

14-15

tot
amb
stg
j

− 12 V

− 10 V

− V

− V

P
P

V
V

−−0.6 V

−−0.6 V

− 200 mA

− 300 mW

−40 + 80 °C

−55 + 150 °C

− + 125 °C

Note

1. Mounted on epoxiprint.

THERMAL RESISTANCE

From junction to ambient R

Note

1. Mounted on epoxiprint.

th j-a

300 K/W
160 K/W

(1)

March 1989 5

Philips Semiconductors Product specification

AM receiver circuit TDA1072AT

CHARACTERISTICS

= V

V

P

measurements are with respect to ground (pin 16); unless otherwise specified

Supplies

Supply voltage (pin 13) V
Supply current (pin 13) I

RF stage and mixer

Input voltage (DC value) V
RF input impedance at

V

RF input impedance at

V

IF output impedance R

Conversion transconductance

before start of AGC I
Maximum IF output voltage,

inductive coupling to pin 1,

(peak-to-peak value) V
DC value of output current

(pin 1) at V
AGC range of input stage − 30 − dB
RF signal handling capability:

input voltage for THD = 3%

at m = 80% (RMS value) V

Oscillator

Frequency range ∆f 0.6 − 60 MHz
Oscillator amplitude

(pins 11 to 12)

(peak-to-peak value) V
External load impedance R
External load impedance for

no oscillation R
Ripple rejection at V

= 100 mV (RMS value);

f

p

(RR = 20 log [V

13-16

= 8.5 V; T

= 25 °C; fi = 1 MHz; fm = 400 Hz; m = 30%; fIF = 460 kHz; measured in test circuit of Fig.1; all

amb

PARAMETER CONDITIONS SYMBOL MIN. TYP. MAX. UNIT

13

13

14-15

< 300 µVR

I

> 10 mV R

I

= 0 V I

I

P

14-15

C

14-15

14-15

C

14-15
1

C

1

1/VI

1(p-p)

1

I(rms)

11-12(p-p)
11-12(ext)

11-12(ext)

7.5 8.5 10 V
15 23 27 mA

− VP / 2 − V

− 5.5 − kΩ

− 25 − pF

− 8 − kΩ

− 22 − pF
500 0 0 kΩ

− 6 − pF

− 6.5 − mA/V

− 5 − V

− 1.2 − mA

− 500 − mV

− 130 150 mV

0.5 − 200 kΩ

−−60 Ω

= 100 Hz

])

13/V11

March 1989 6

Philips Semiconductors Product specification

AM receiver circuit TDA1072AT

PARAMETER CONDITIONS SYMBOL MIN. TYP. MAX. UNIT

Source voltage for switching

diodes (6 × V

)V

BE

DC output current (for

switching diodes) V

P

= V

13

≤ 9 V I

Change of output voltage at

= 20 mA (switch to

∆I

11

maximum load) ∆V

Buffered oscillator output

DC output voltage V
Output signal amplitude

(peak-to-peak value) V
Output impedance R
Output current I

IF, AGC and AF stages

DC input voltage V
IF input impedance R

C

IF input voltage for

THD = 3% at m = 80% V
Voltage gain before start

of AGC V
AGC range of IF stages:

change of V

change of V

V

= 75 mV ∆V

3-4(ref)

3-4
O(AF)

for 1 dB

;

AF output voltage at

= 50 µVV

V

3-4(IF)

AF output voltage at

V

= 1 mV V

3-4(IF)

AF output impedance (pin 6) Z

Indicator driver

Output voltage at

= 0 mV R

V

I

= 2.7 kΩ V

L(9)

Output voltage at

VI= 500 mV R

= 2.7 kΩ V

L(9)

Load resistance R

11

11

11

10

10(p-p)
10

10(peak)

3-4
3-4
3-4

3-4

3-4/V6

3-4

O(AF)

O(AF)

−3.5 − kΩ

O

9

9
L(9)

− 4.2 − V

0 − 5mA

− 0.5 − V

− 0.7 − V

− 320 − mV

− 170 −Ω

−−−3mA

− 2 − V

2.4 3.0 3.9 kΩ

− 7 − pF

− 90 − mV

− 68 − dB

− 55 − dB

− 130 − mV

− 310 − mV

− 20 150 mV

2.5 2.8 3.1 V

2.7 −−kΩ

March 1989 7