AN618 Panasonic Semiconductor, AN618 Datasheet - Page 20

• Manufacturer Part Number: AN618
• Description: Recording and playing amplifier IC for answering telephones
• Manufacturer: Panasonic Semiconductor

AN6175K
20
Pin No.
Detailed Pin Descriptions(cont.)
31
32
33
34
35
36
37
HS, HF/MF
HS/HF
Vr
ST
MFI
HF1
V
CC
2
Symbol
[Mode switching(handset/hands-free)]
This pin must be connected to V
the HS mode (SW1 to a), or to GND for
the HF mode (SW1 to b).
[Reference for the handset or hands-free
mode]
The voltage equal to half the V
age is output.
[Input to the base of the power supply
This pin connects to the base of Q4.
[MF input]
MF signals are input to this pin through
C35(0.1 F). The input impedance,
Zin=20 k .
[From transmitter att. output(hands-free
The transmitter attenuator output is sent
from Pin18 to this pin through C37(0.1
[Transmission amp. AC impedance setting]
This pin connects to V
(100 F)and to the collector of Q3 (trans-
mission transistor)through R38(330 ).
[Mode switching(handset or hands-free
/MF)]
This pin must be connected to V
the HS or HF mode(SW2 to a), or to
GND for the MF mode (SW2 to b).
transistor]
mode)]
F). The input impedance, Zin=20 k .
Description
CC
1 through C38
CC
CC1
1 volt-
CC1
for
for
35
32
20k
31
Equivalent circuit
V
V
50k
50k
CC
CC
100k
100k
1
1
ICs for Telephone
–
–
34
33
36