LA75525AVA
Continued from preceding page.
Pin No. Pin name
Function
Equivalent circuit
13 1st SIF INPUT First SIF input. ADC cut capacitor must be used in the input
circuit.
2kΩ
If a SAW filter is used:
The first SIF sensitivity can be increased by inserting an inductor
between the SAW filter and the IC to neutralize the SAW filter
2kΩ
output capacitance and the IC input capacitance.
When used in an intercarrier system:
This pin (pin 13) maybe connect to GND.
20kΩ
100kΩ
12pF
100Ω
30pF
13
RF AGC
OUTPUT
RF AGC OUT PUT. This output controls the tuner RF AGC.
A protective 200Ω resister is inserted in series with the open
collector out put. Determine the external bleeder resister value in
accordance with the specifications of the tuner.
14
200Ω
15 AFT MUTE
LEVEL
The MUTE voltage of AFT is set up this pin. It becomes a voltage
that generated by an external bleeder resistor, when this pin is
connected with GND. It becomes a High voltage (VCC) when this
pin is leaving open.
16 IF AGC INPUT IF AGC filter connection.
The signal peak-detected by the built-in AGC detector is
converted to the AGC voltage at pin 16. Additionally, a second
AGC filter (a lag-lead filter) used to create the dual time constants
is provided internally in the IC.
Use a 0.022µF capacitor as the external capacitor, and other
characteristics.
67Ω
VCC
50kΩ
1kΩ
15
1kΩ
10kΩ
80kΩ
30kΩ
VCC
1kΩ
1kΩ
17 VIF IN 2
18 VIF IN 1
VIF amplifier input.
The input circuit is a balanced circuit, and the input constants are:
R = 1.0kΩ
C = 3pF
19 GND
GND
16
1kΩ
100Ω
1kΩ
100Ω
20kΩ
17 18
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