MT9094 Mitel Networks Corporation, MT9094 Datasheet - Page 5

• Manufacturer Part Number: MT9094
• Description: ISO2-CMOS ST-BUS FAMILY Digital Telephone (DPhone-II)
• Manufacturer: Mitel Networks Corporation

On PWRST (pin 6) the Filter/CODEC defaults such
that the side-tone path, dial tone filter and 400Hz
transmit filter are off, all programmable gains are set
to 0dB and µ-Law companding is selected. Further,
the Filter/CODEC is powered down due to the PuFC
bit (Transducer Control Register, address 0Eh) being
reset. This bit must be set high to enable the Filter/
CODEC.
The internal architecture is fully differential to provide
the best possible noise rejection as well as to allow a
wide dynamic range from a single 5 volt supply
design.
continued into the Transducer Interface section to
provide full chip realization of these capabilites.
Note: *gain the same for A-Law and m Law
SERIAL
PCM
PCM
PORT
This
DIGITAL DOMAIN
DSP GAIN*
Transmit
+22.5 dB
Handsfree
Receive
+22.5 dB
Ringer &
(1.5dB
–72 to
steps)
DTMF,
(1.5dB
–72 to
steps)
fully
Tone
Internal to Device
differential
FILTER/CODEC
architecture
-Law –11 dB
(3.32 dB steps)
-Law –18.8 dB
(1 dB steps)
(1 dB steps)
Filter Gain
0 to –7 dB
Filter Gain
0 to +7dB
Side-tone
Side-tone
Transmit
Receive
+9.96dB
Nominal
–9.96 to
Gain
Figure 3 - Audio Gain Partitioning
is
Speaker Gain
-Law 6.1dB
-Law 15.4dB
A reference voltage (V
requirements of the CODER section, and a bias
voltage (V
sections, are both generated on-chip. V
brought to an external pin so that it may be used for
biasing any external gain plan setting amplifiers. A
0.1µF capacitor must be connected from V
analog ground at all times. Likewise, although V
may only be used internally, a 0.1µF capacitor from
the V
suggested that the analog ground reference point for
these two capacitors be physically the same point.
To facilitate this the V
on adjacent pins.
The transmit filter is designed to meet CCITT G.714
specifications. The nominal gain for this filter path is
0dB (gain control = 0dB).
(8 dB steps)
0 to –24 dB
-6 dB
TRANSDUCER INTERFACE
Ref
ANALOG DOMAIN
pin to ground is required at all times. It is
Bias
Transmit
Gain
), for biasing the internal analog
-Law –6.3 dB
-Law –3.7 dB
from DSP)
Receiver
Speaker
0.2dB*
Phone
Ringer
Driver
Driver
(input
Tone
Ref
M
U
X
and V
Ref
), for the conversion
An anti-aliasing filter is
Bias
HSPKR+
HSPKR–
SPKR+
SPKR–
-6 dB
MIC+
MIC–
M+
M–
External to Device
pins are situated
75
MT9094
75
Handsfree
mic
Transmitter
microphone
Speakerphone
(40 nominal)
Bias
(32 min)
Speaker
Handset
Receiver
(150 )
is also
Bias
7-49
Ref
to