Pioneer DEH-1850 Service Manual page 55

5
- FM/AM Tuner Unit
QQ
3 7 63 1515 0
AM ANT
1 ATT
FM ANT
3
ATT
ANT adj
No. Symbol
1 AMANT
2 RFGND
TE
L 13942296513
3 FMANT
4 VCC
5 SL
6 CE2
7 NC
8 CE1
9 CK
10 DI
11 NC
12 OSCGND
13 ROM_VDD
14 DO
15 DGND
16 NC
17 VDD_3.3
18 NC
19 NC
20 NC
21 NC
22 AUDIOGND
23 L ch
24 R ch
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7 6
IC 3 EEPROM
5.0V
OSC
FMRF
IC 1
3.3V
FMRF
MIXER, IF AMP
RF adj
2 12 15 22 16
I/O Explain
I AM antenna input AM antenna input high impedance AMANT pin is connected with
an all antenna by way of 4.7µH. (LAU type inductor) A series circuit
including an inductor and a resistor is connected with RF ground for
the countermeasure against the hum of power transmission line.
RF ground Ground of antenna block
I FM antenna input Input of FM antenna 75Ω Surge absorber
The power supply for analog block. D.C 8.4V ± 0.3V
power supply
O signal level Output of FM/AM signals level
I chip enable-2 Chip enable for EEPROM "Low" active
non connection Not used
I chip enable-1 Chip enable for AF•RF "High" active
I clock Clock
I data in Data input
non connection Not used
osc ground Ground of oscillator block
power supply Power supply for EEPROM pin 13 is connected with a power supply of
micro computer.
O data out Data output
digital ground Ground of digital block
non connection Not used
The power supply for digital block. 3.3V ± 0.2V
power supply
non connection Not used
non connection Not used
non connection Not used
non connection Not used
audio ground Ground of audio block
O L channel output FM stereo "L-ch" signal output or AM audio output
O R channel output FM stereo "R-ch" signal output or AM audio output
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2 9
8
13 5 10 9 8 11 14
IC 5
5V 3.3V
LPF
T51
CF52
IC 4
3.3V 2.5V
2.5V
3.3V
4 17
Q Q
3 6 7 1 3
.
DEH-1850/XN/ES
7
9 4 2 8
18 19 20 21
IC 2
2.5V
DET, FM MPX
1 5 0 5 8 2 9 9 4
(DSP-201M-S00B)
m
co
7
8
9 9
A
Rch
24
Lch
23
B
C
2 8 9 9
is necessary.
D
E
F
55
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