TDA1574T Philips Semiconductors, TDA1574T Datasheet - Page 4

• Manufacturer Part Number: TDA1574T
• Description: Integrated FM tuner for radio receivers
• Manufacturer: Philips Semiconductors

Philips Semiconductors
PINNING
FUNCTIONAL DESCRIPTION
Mixer
The mixer circuit uses a double balanced multiplier with a preamplifier (common base input) in order to obtain a large
signal handling range and low oscillator radiation.
Oscillator
The oscillator circuit uses an amplifier with a differential input. Voltage regulation is achieved by utilizing the symmetrical
tan h-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 narrowband information (keyed AGC) or by a
wideband/narrowband information only. If narrowband AGC is required pin 3 should be connected to pin 5. If wideband
AGC is required pin 14 should be connected to pin 15.
August 1990
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Integrated FM tuner for radio receivers
Mixer input 1
Mixer input 2
Wideband information input
Ground
Voltage reference
Oscillator output
Oscillator input 1
Oscillator input 2
Buffered oscillator output
Not connected
Not connected
IF output
Standby switch
Narrowband information input
IF input 1
IF input 2
Supply voltage
Mixer output 1
Mixer output 2
AGC output
4
Fig.2 Pinning diagram.
Product specification
TDA1574T