AN618 Panasonic Semiconductor, AN618 Datasheet - Page 15

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

ICs for Telephone
Pin No.
Detailed Pin Descriptions
1
2
3
4
5
MAO(HF)
MAI(HF)
MAI(HS)
MAO(HS)
TND
Symbol
[MIC preamplifier output in the HF mode]
Amplified HF mode transmitter signals
are output from this pin through C7(0.1
the LOG amp.1 input. The output impe-
dance, Zout 50 .
[MIC preamplifier input in the HF mode]
HF mode transmitter signals are input
from ECM. Use R9 and R10 to adjust the
transmitter signal gain, and use C3 and
C44 to adjust the frequency characteris-
tics.
[MIC preamplifier input in the HS mode]
HS mode transmitter signals are input
from the handset MIC. Use R12 and R13
to adjust the transmitter signal gain, and
use C6 and C45 to adjust the frequency
characteristics.
[MIC preamplifier output in the HS mode]
Amplified HS mode transmitter signals
are output from this pin.
impedance, Zout 1 k .
[Noise detecting circuit control]
Turns ON or OFF the background-noise
detecting circuit in the HS mode. The
circuit turns ON if this pin is grounded
through C7(SW7 to a), and turns OFF if
this pin is grounded directly(SW7 to b).
F)and R15(5.1 k )to pin 7 to become
Description
The output
HF mode MIC
preamplifier
HS mode MIC
preamplifier
3
2
Equivalent circuit
V
40
40
V
CC
V
CC
1
CC
1
1
To the line driver
To the transmitter
attenuator
AN6175K
5
1
4
15