TCA440 Datasheet, PDF (3/11 Pages) Siemens Semiconductor Group – AM Receiver Circuit

Functional description
It contains several function units, which enable designing and assembling of efficient AM tuners. Caused by
internal voltage stabilization characteristics are rather independent from supply voltage.
The RF input signal reaches via a controllable and overdriving proof preselector stage a balanced mixer. By
means of a RF - signal generated by a separated oscillator the input signal is transported into IF. Multiplicative
mixing causes only few harmonic content. Gain control is carried out by means of two separated feedback control
loops for preselector stage and IF amplifier. By these a loop bandwidth of approximately 100 dB is obtained. The
control voltage of the IF - amplifier can be used to drive a moving - coil instrument (field strength indicator). The IF
amplifier consists of 4 amplifier stages, the first, second and third can be controlled. The bandwidth of the IF
amplifier is approximately 2 MHz and on that account sufficient for usual IF frequencies in the AM range of
approximately 460 kHz.
The symmetrical arrangement of the entire circuitry guarantees well oscillating. The bridge of the mixer avoids
direct breakdown.
Absolute maximum ratings
Supply voltage
Junction temperature
Ambient operating temperature
Storage temperature
Total thermal resistance
V_CC
T_j
T_a
T_s
R_thja
min
max
unit
4.5
15.0
V
150
°C
-15
80
°C
-40
125
°C
120
K/W
Recommended operational conditions
Supply voltage
V_CC
Ambient operating temperature
T_a
min
max
unit
4.5
15
V
-10
70
°C
12/95
3
TCA 440 / T