ICs for FM/AM Tuner
s
Pin Descriptions (Cont.)
Pin No.
Pin Name
Typ. Waveform
7.2V
AN7243S
Description
Drive PIN diode for input attenuate
of RF-Amp.
Determine drive current by Pin12
external resistance.
Equivalent Circuit
V
CC
12
PIN Diode
Driver Output
.0V
12
2.2kΩ
13
Mix.Output
RF
Input signal from RF Amp.
13
2.2kΩ
14
GND
Main circuit GND
Note) Typical waveform frequency is the value when tuning receiving frequency 98.0 MHz.
s
Supplementary Explanation
• AGC
AGC used at the AN7243S uses mixer output (IFT primary side) signal and controls AGC output.
IFT
RF
Amp.
Mixer
IF – Amp.
AGC
Amp.
6
R
Adj.
(S
AGC
variable)
–
12
+
AGC
Det.
V
5
, V
12
–V
IN (RF)
8
7
AGC Voltage (V)
6
5
4
3
2
1
0
V
12
Variable
V
5
V
CC
= 8V
S
AGC
V
IN (RF)
(dBµ)
PANASONIC [ PANASONIC SEMICONDUCTOR ]
