LA1787M Datasheet, PDF (40/54 Pages) Sanyo Semicon Device – Single-Chip Tuner IC for Car Radios

LA1787M
• AM high band cut and detector output level adjustment methods
The pin 31 AM and FM tuner output has an impedance of 10 kΩ in AM mode and a few tens of Ohms in FM
mode. Therefore, R31 is used to lower the AM detector output level and C31 determines the AM high band
frequency characteristics.
FM
detector
VCC
31
R31
C31
VCC
+
AM
detector
10 kΩ
Noise
canceler
input
30
50 kΩ
• AM stereo system pins
VCC
IFT
45
Fig. 39
A12086
GND
To the AM stereo decoder
400 mV rms
450 kHz output
39
VCC
50 pF _{150 Ω}
IF AMP.
Fig. 40
Keyed AGC
A11761
No. 6655-40/54