LA1776M_09 Datasheet, PDF (15/41 Pages) Sanyo Semicon Device – Single-Chip Tuner IC for Car Radios

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Pin No.
Pin
LA1776M
Description
Pin 30 is the noise canceller input. The input
impedance is 50 kΩ
30 Noise canceller input
Pin 31 is the AM and FM detector output
In FM mode, this is a low-impedance output.
31 AM/FM detector output
In AM mode, the output impedance is 10 kΩ.
The AM detection output can be modified by
adjusting the value of R.
Equivalent circuit
VCC
FM
detector
output
31
10 kΩ
R
AM
detector
output
VCC
30
Noise
canceller
50 kΩ
+
0.22 µF
32 IF S-meter output
FM S-meter output block
VCC
VSM
32
10 kΩ
29
1000 pF
33 Mute drive output
• The muting time constant is determined by an
external RC circuit as described below.
Attack time: TA = 10 kΩ × C1
Release time: TR = 50 kΩ × C1
• Noise convergence adjustment
The noise convergence when V33 is 2 V will be
about 40 dB.
(The basis can be varied from 5 to 35 dB for a 1
kHz 22.5 kHz deviation output.)
*: There is no hole detection function.
• Muting off function
The muting function is turned off by a 4 kΩ resistor
between pin 33 and ground.
SEEK
OFF
SOFT
MUTE
C1
0.022 µF
VCC
33
MUTE
AMP.
10 kΩ 50 kΩ
Band
muting
SD circuit
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