Power Supply Circuits; Port Allocations - Icom IC-4088SR Service Manual

4-4 POWER SUPPLY CIRCUITS

VOLTAGE LINE
LINE
The voltage from the connected battery or
VCC
power supply from DC IN (J302).
Common 3 V converted from the VCC line at the
+3V regulator circuit (IC303). The circuit outputs
C3V
the voltage regardless of the power ON/OFF
condition.
Common 3 V converted from the VCC line at the
+3V
+3V current amplifier (Q303, D301).
Receive 3 V controlled by the R+3 current
R+3 amplifier (Q304) using the "RXC" signal from the
CPU (IC301, pin 59).
Transmit 3 V converted from the VCC line at the
T+3 current amplifier (Q305, Q308, Q319,
T+3
D302, D303, D305) using the "TXC" signal from
the CPU (IC301, pin 65).

4-5 PORT ALLOCATIONS

4-5-1 D/A CONVERTER (RF unit; IC3)
Pin Port
number name
Outputs the deviation control signal.
1 MODC
Outputs the TX power control signal.
2 PWRC
Outputs the PLL reference frequency
3 FC
control signal.
4-5-2 CPU (MAIN unit; IC301)
Pin Port
number name
Input port for the test mode switch.
27 TEST
Outputs the clock signal to the EEP-
31 EEPCK
ROM (MAIN unit; IC300).
Outputs the data signals to the EEP-
32 EEPDA
ROM (MAIN unit; IC300).
Input port for the control signal of the
33 DETOUT
tone detection
Outputs the shift control signal to the
35 SHIFT
PLL IC (RF unit; IC2).
Outputs the strobe signals to the PLL
36 PLSTB
IC (RF unit; IC2).
Outputs the clock signal to the PLL IC
37 CK
(RF unit; IC2).
Outputs the data signals to the PLL IC
38 DATA
(RF unit; IC2).
DESCRIPTION
Description
Description
Pin Port
number name
Input port for the PLL unlock signal from
the PLL IC (RF unit; IC2).
41 UNLK
Input port for the PTT switch from the
external mic jack (MAIN unit; J303).
42 PTT
switch is pushed.
Input port for the control signal from the
43 MICIN
external remote microphone.
Input port for the transceiver's internal
44 TEMP
temperature.
Input port for the squelch level signal.
46 SQLIN
Input port for connected battery pack
47 VIN
voltage.
Input port for [MODE] switch.
51 MODE
Input
52 POWSW
Outputs the beep audio signal.
53 BEEP
Input port for [DOWN] switch.
54 DOWN
Input port for [UP] switch.
55 UP
Input port for the internal PTT switch.
56 PTTSW
Outputs the control signal of LCD back
57 LAMPO
light.
Outputs the control signal of the AF
amplifier regulator circuit (MAIN unit;
58 AFON
Q306, Q307, Q311).
Outputs the control signal of the R+3
59 RXV
regulator circuit (MAIN unit; Q304).
Outputs the microphone mute signal
for RING function.
61 MMUTE
Outputs the internal microphone con-
trol signal.
62 MICSW
Outputs the control signal of the +3V
regulator circuit (MAIN unit; Q303,
63 POWER
D301).
Outputs the control signal of the vol-
ume mute switch (MAIN unit; Q316).
64 RMUTE
Outputs the control signal of the T+3
regulator circuit (Q305, Q308, D303,
65 TXV
D304).
Outputs the control signal of the charge
66 CHGC
circuit (Q312, Q314, D305, D308).
4 - 3
Description
Low : During unlock.
Low : External microphone PTT
port for [POWER]
Low : While [POWER] switch is
pushed.
Low : While [PTT] switch is pushed.
High : While RING signals are out-
put, etc.
High : While the internal PTT switch
is pushed.
High : While squelched.
switch.