
LA1845N
No.7185-5/9
Continued from preceding page.
Pin No.
Pin function
Pin voltage (V)
Pin description
Equivalent circuit
11
Phase comparator
low-pass filter
(AM/FM switching)
VCC-1.0
The device operates in AM mode when a current of
over 200
μA flows from pin.12.
Limit values for the resistor :
2.7k
Ω (When VCC = 7V)
3.9k
Ω (8V)
11
12
Pilot detector
low-pass filter
(Forced mono)
(VCO stop)
VCC-1.0
The device is forced to monaural when a current of
over 50
μA flows from this pin.
The VCO is stopped when a current of over 200
μA
flows from this pin.
The limit values for the resistor are the same as
those for pin 11.
12
13
14
L outputs
R outputs
3.2
Output impedance ro = 3.3kΩ
13
( 14 )
15
Pilot canceler output
Vreg
15
3
16
Decoder input
Vreg
Inverting input pin
RNF = 20k
Ω
RNF
16
17
PLL input
Vreg
Input impedance ri = 20kΩ
17
18
FM demodulator
output
Vreg + 0.7
Output impedance ro = 2.3kΩ
The channel separation can be adjusted with an
external capacitor connected between this pin and
ground.
18
19
AM detector output
0 (FM)
1.5 (AM)
Output impedance ro = 10kΩ
100V
19
20
S meter,
AM AGC
0.2 (FM)
0.9 (AM)
The resistance of the built-in resistor R is 13.9k
Ω
The SD responce during seek operation is
determined with the external capacitor connected to
this pin.
20
R
21
AM RF input
Vreg
Must be used at the same potential as pin 22.
21
22
AFC
Vreg
The FM SD bandwidth can be adjusted with the
external resistor connected between this pin and
pin 3 (Vreg).
22
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