TCA440 specifications
Bat detector page
Main homepage
mail me !
 Below some of the specifications of the TCA440 are given. This text is part of the specifications of Signetics (now part of Philips, I think). The actual IC that I bought has chip number A244D, N9.
Also check out this pdf.

AM receiver circuit

TCA440 block diagram

Description

TCA 440 is a monolithic IC, especially developed for AM receivers up to 50 Mhz. It includes a RF stage with AGC, a balanced mixer, separate oscillator and an IF amplifier with AGC. Because of its low current consumption and of its internal stabilisation the TCA 440 is perfectly suited for battery operated portables, car and home radios.

Tuning meter

Recommended instruments:
500 micro-A (R1=800 Ohm) or 300 micro-A (R1=1.5 kOhm)
The IC offers at pin 10 a tuning meter voltage of 600 mV-EMP max. with a source impedance of approx. 400 Ohm.

Function

As pictured in the circuit diagram the TCA 440 comprises two control loops independent of each other which control the RF stage amd the IF stages. By AGCing the RF stage, excellent signal handling is obtained. A voltage of 2.6 Vpp on the IC input can be handled with very low distortion. The push-pull mixer operates multiplicatively, thereby resulting in few harmonic mixing products and whistling points. The oscillator which is separated from the mixer is also apted excellently for short waves. From the AGC of the RF amplifier a voltage is derived for a tuning meter which can be connected directly to the meter. The symmetric composition of the circuit provides high stability against oscillation and, at the same time, an AGC range of more than 100 dB. The bridge circuit provides good isolation of the oscillator.

Absolute maximum ratings

VccSupply voltage 15V
TambAmbient temperature in operation -15 to +80deg. C
TsStorage temperature -30 to +125deg. C
VccRange of operation 4.5 to 15V

Features

  • Balanced circuit
  • Separately controllable prestage
  • Multiplicative push-pull mixer with separate oscillator
  • High signal handling capability even with 4.5 V supply voltage
  • 100 dB feedback control range in 5 stages
  • Direct connection for tuning meter
  • Minimum external components

PIN CONFIGURATION

N package
RF input1
 16Mixer output
RF input2
 15Mixer output
AGC RF stage3
 14Supply
Multiplier input4
 13IF decouple
Multiplier input5
 12IF input
Oscillator6
 11IF input
IF output7
 10Meter output
Ground8
 9AGC IF stage

This page was last updated on Saturday, January 29, 2000