MT9092AP Zarlink, MT9092AP Datasheet - Page 6

• Manufacturer Part Number: MT9092AP
• Description: Digital Telephone 44-Pin PLCC Tube
• Manufacturer: Zarlink

Specifications of MT9092AP

• Package: 44PLCC
• Power Supply Type: Analog
• Typical Supply Current: 8 mA
• Typical Operating Supply Voltage: 5 V
• Minimum Operating Supply Voltage: 4.75 V
• Maximum Operating Supply Voltage: 5.25 V

Digital Signal Processor
The DSP block is located, functionally, between the serial ST-BUS port and the Filter/CODEC block. Its main
purpose is to provide both a digital gain control and a half-duplex handsfree switching function. The DSP will also
generate the digital patterns required to produce standard DTMF signalling tones as well as single tones and a tone
ringer output. A programmable (ON/OFF) offset null routine may also be performed on the transmit PCM data
stream. The DSP can generate a ringer tone to be applied to the speakerphone speaker during normal handset
operation so that the existing call is not interrupted.
The main functional control of the DSP is through two hardware registers which are accessible at any time via the
microport. These are the Receive Gain Control Register at address 1Dh and the DSP Control Register at address
1Eh. In addition, other functional control is accomplished via multiple RAM-based registers which are accessible
only while the DSP is held in a reset state. This is accomplished with the DRESET bit of the DSP Control Register.
Ram-based registers are used to store transmit gain levels (20h for transmit PCM and 21h for transmit DTMF
Note: *gain the same for A-Law and µ−Law
SERIAL
PCM
PCM
PORT
DIGITAL DOMAIN
DSP GAIN*
+22.5 dB
Handsfree
Transmit
+22.5 dB
Receive
Ringer &
(1.5dB
–72 to
steps)
DTMF,
(1.5dB
–72 to
steps)
Tone
Internal to Device
FILTER/CODEC
µ-Law –11 dB
Α-Law –18.8 dB
(3.32 dB steps)
(1 dB steps)
(1 dB steps)
Filter Gain
0 to –7 dB
Filter Gain
0 to +7dB
Figure 3 - Audio Gain Partitioning
Side-tone
Side-tone
Transmit
Receive
+9.96dB
–9.96 to
Nominal
Gain
Zarlink Semiconductor Inc.
MT9092
6
µ-Law 6.1dB
Α-Law 15.4dB
Speaker Gain
(8 dB steps)
0 to –24 dB
-6 dB
TRANSDUCER INTERFACE
ANALOG DOMAIN
Transmit
Gain
µ-Law –6.3 dB
Α-Law –3.7 dB
from DSP)
Receiver
Speaker
0.2dB*
Phone
Ringer
Driver
Driver
(input
Tone
M
U
X
HSPKR+
HSPKR–
SPKR+
SPKR–
-6 dB
MIC+
MIC–
M+
M–
External to Device
75
75
Data Sheet
Handsfree
mic
Transmitter
microphone
Speakerphone
(40Ω nominal)
(32Ω min)
Speaker
Handset
Receiver
(150Ω)