msm7502 Oki Semiconductor, msm7502 Datasheet - Page 7
![no-image](/images/no-image-200.jpg)
msm7502
Manufacturer Part Number
msm7502
Description
Multi-function Pcm Codec Msm7502multi-function Pcm Codec
Manufacturer
Oki Semiconductor
Datasheet
1.MSM7502.pdf
(35 pages)
¡ Semiconductor
MSM7502
TPBI, TO
TPBI is the input and TO is the output of the transmit pre-amplifier (B).
When the handset is used, TPBI is connected to the transmit pre-amplifier (A) output pin (TPAO).
If adjustment of frequency characteristics on the transmit path is required, insert a circuit for
adjustment of characteristic between TPAO and TPBI. Through processor control, the signal
applied to this pin is output via the TO pin on the transmit path and its side tone via the RPO pin.
During the whole system power down mode, TO is at an analog ground level. The typical gain
between TPBI and TO is +17.7 dB. Through processor control, a gain between +17.7 dB and +8.7
dB is also settable at 3 dB steps.
The typical gain between TPBI and RPO is +3.0 dB. Through processor control, a gain between
–9 dB and +9 dB is variable in 3 dB steps. Changing the gain between TPBI and TO may change
the gain between TPBI and RPO. TPBI is a high impedance input, so insert an about 100 kW
resistor between TPBI and SGT.
A circuit example for adjustment of frequency characteristics
TPAO
TPBI
SGT
R3
C3
R4
C4
MPAI, MPAO
Handfree microphone pre-amplifier (A) input and output.
MPAI is the input and MPAO is the output. The speech path between MPAI and MPAO is always
active regardless of processor control. During the whole system power saving mode, MPAO is
at an analog ground level. The gain between MPAI and MPAO is typically +20 dB. Through
processor control, gains between +14 dB and +11 dB are also settable. MPAI is a high impedance
input, so insert an about 100 kW between MPAI and SGT.
MPBI, MPBO
The handfree microphone (B) input and output.
MPBI is the inverted input and MPBO is the output. With an external resistance, the amplifier
gain is adjusted in the range between –25 dB and +25 dB. A signal on the MPBO is output via the
TO pin through processor control. During the whole system power down mode, MPBO is at an
analog ground level. The gain between MPBO and TO is fixed to 0 dB.
7/35