February 1985 4
Philips Semiconductors Product specification
Integrated FM tuner for radio receivers TDA1574
FUNCTIONAL DESCRIPTION
Mixer
The mixer circuit is a double balanced multiplier with a preamplifier (common base input) to obtain a large signal handling
range and a low oscillator radiation.
Oscillator
The oscillator circuit is an amplifier with a differential input. Voltage regulation is achieved by utilizing the symmetrical
tanh-transfer-function to obtain low order 2nd harmonics.
Linear IF amplifier
The IF amplifier is a one stage, differential input, wideband amplifier with an output buffer.
Keyed AGC
The AGC processor combines narrow- and wideband information via an RF level detector, a comparator and an ANDing
stage. The level dependent, current sinking output has an active load, which sets the AGC threshold.
The AGC function can either be controlled by a combination of wideband and narrowband information (keyed AGC), or
by a wideband information only, or by narrowband information only. If only narrow-band AGC is wanted pin 3 should be
connected to pin 5. If only wideband AGC is wanted pin 12 should be connected to pin 13.
RATINGS
Limiting values in accordance with the Absolute Maximum System (IEC 134)
THERMAL RESISTANCE
Note
All pins are short-circuit protected to ground.
Supply voltage (pin 15) V
P
= V
15-4
max. 18 V
Mixer output voltage (pins 16 and 17) V
16, 17-4
max. 35 V
Standby switch input voltage (pin 11) V
11-4
max. 23 V
Reference voltage (pin 5) V
5-4
max. 7 V
Field strength input voltage (pin 12) V
12-4
max. 7 V
Total power dissipation P
tot
max. 800 mW
Storage temperature range T
stg
−55 to + 150 °C
Operating ambient temperature range T
amb
−40 to + 85 °C
From junction to ambient (in free air) R
th j-amb
= 80 K/W