mt91l61asr1 Zarlink Semiconductor, mt91l61asr1 Datasheet - Page 6

• Manufacturer Part Number: mt91l61asr1
• Description: 3 V Multi-featured Phone Codec With Programmable U/a Law Companding
• Manufacturer: Zarlink Semiconductor

Transducer Interfaces
Standard handset transducer interfaces are provided by the MT91L60/61. These are:
•
•
Serial
D
D
The handset microphone inputs (transmitter), pins M+/M-. The nominal transmit path gain may be adjusted
to either 6.0 dB or 15.3 dB. Control of this gain is provided by the TxINC control bit (Gain Control register 1,
address 00h).
The handset speaker outputs (receiver), pins HSPKR+/HSPKR-. This internally compensated fully
differential output driver is capable of driving the load shown in Figure 3. The nominal receive path gain may
be adjusted to either 0 dB, -6 dB or -12 dB. Control of this gain is provided by the RxINC control bit (Gain
Control register 1, address 00h). This gain adjustment is in addition to the programmable gain provided by
the receive filter.
in
out
PCM
PCM
Port
Encoder
Decoder
0 to +7 dB
Transmit Filter
(1 dB steps)
0 to +7 dB
(1 dB steps)
Gain
Filter Gain
0 to -7 dB
+ Full Scale
(quiet code)
- Full Scale
Receive
Gain
Filter/Codec and Transducer Interface
Code
+ Zero
-Zero
Figure 3 - Audio Gain Partitioning
Internal To Device
-0.37 dB or 8.93 dB
Magnitude
0000 0000
1000 0000
1111 1111
0111 1111
Zarlink Semiconductor Inc.
Transmit Gain
Sign/
(3.32 dB steps)
MT91L60/61
+9. 96 dB
Side-tone
-11 dB
-9.96 to
-6 dB
Table 1
Default Bypass
6
1000 0000
1111 1111
0111 1111
0000 0000
µ-Law
ITU-T (G.711)
Transmit
6.37 dB
Gain
-6.0 dB or
Receiver
1010 1010
1101 0101
0101 0101
0010 1010
Driver
A-Law
0 dB
HSPKR +
HSPKR -
M+
M
External To Device
-
75Ω
75Ω
Transmitter
Microphone
Data Sheet
Receiver
Handset
(150Ω)