Continued from preceding page.
Pin Number Pin Name Pin Voltage
LA8638NV
Equivalent Circuit
VREF
+
Indeterminate
25
CMP-RCT (when there is IN
–
no signal)
15kΩ
Description
VCC
25
Full-wave rectifier output for compressor
block (AC smoothing)
26
MIC-OUT
VCC/2
28
+
27
MIC-IN2
VCC/2
500Ω
27
–
28
MIC-IN1
VCC/2 power
supply
500Ω
30
TX-LVL-ADj
VCC/2
IN
30
29kΩ
+
–
20kΩ
20 VCC= 2.4V
fin = 1kHz
0
–20
–40
I/O Characteristics
TX-OUT (pin 23)
–60
–80
–100
–160 –140 –120 –100 –80 –60 –40 –20 0
Input level, VIN — dBV
Splatter Filter Frequency Characteristics
10
VCC = 2.4 V; resistance at pin 24 = 4.3 kΩ
0
–10
–20
–30
–40
–50
–60
0.1
23
5 7 1.0 2 3 5 7 10
Frequency, f — kHz
23 5
VCC
26
A13537
TO CMP IN
A13538
Microphone amplifier output
Microphone amplifier negative input
Microphone amplifier positive input
Pin for setting amplification for transmitter
output level switching
A13539
–50 VCC= 2.4V
1kHz- BPF
–60
–70
–80
–90
–100
Crosstalk Characteristics
RX → TX (pin 23)
TX-MUTE (pin 23)
TX → RX (pin 10)
RX-MUTE (pin 10)
–110
–60
–50
–40
–30
–20
–10
0
Input level, VIN — dBV
7 no signal
6
Current Drain —. VCC
BTL on
5
BTL off
4
3
2
Standby
1
0
1
2
3
4
5
6
7
Power supply voltage, VCC — V
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