MT9196AS Zarlink Semiconductor, Inc., MT9196AS Datasheet - Page 5

• Manufacturer Part Number: MT9196AS
• Description: Integrated Digital Phone Circuit (IDPC)
• Manufacturer: Zarlink Semiconductor, Inc.

On PWRST (pin 5) the Filter/CODEC defaults such
that the side-tone path, dial tone filter and 400 Hz
transmit filter are off, all programmable gains are set
to 0dB and CCITT
Filter/CODEC is powered down due to the control
bits of the Path Control Registers (addresses 12h
and 13h) being reset.
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. This fully differential architecture is continued
into the Transducer Interface section to provide full
chip realization of these capabilities for the handset
and loudspeaker functions.
A reference voltage (V
requirements of the CODEC 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 external gain plan setting amplifiers. A 0.1 F
SERIAL
PORT
PCM
PCM
D
D
in
out
Bias
DIGITAL GAIN
Digital Domain
(3 dB steps)
Receive
(3dB steps)
Transmit
), for biasing the internal analog
& TONES
+21 dB
+21 dB
DTMF,
Ringer
-24 to
-24 to
Tone
-Law is selected. Further, the
Internal To Device
Ref
), for the conversion
FILTER/CODEC
(3.32 dB steps)
Transmit Filter
(1 dB steps)
(1 dB steps)
Filter Gain
0 to +7 dB
0 to -7 dB
Side-tone
Figure 3 - Audio Gain Partitioning
Receive
+9 96dB
-11 dB
-9.96 to
Gain
Bias
is also
or 8.93 dB
-0.37 dB
Trans-
Gain
(4 dB steps)
(4 dB steps)
+8 to -20dB
mit
capacitor must be connected from V
ground at all times. Likewise, although V
be used internally, a 0.1 F capacitor from the V
pin to ground is required at all times. The analog
ground reference point for these two capacitors must
be physically the same point. To facilitate this the
V
The transmit filter is designed to meet CCITT G.714
specifications. The nominal gain for this filter path is
0 dB (gain control = 0 dB). Gain control allows the
output signal to be increased up to 7 dB. An anti-
aliasing filter is included. This is a second order
lowpass implementation with a corner frequency at
25 kHz. Attenuation is better than 32 dB at 256 kHz
and less than 0.01 dB within the passband.
An optional 400Hz high-pass function may be
included into the transmit path by enabling the Tfhp
bit in the Control Register 1 (address 0Eh). This
option
background noise such as motor and fan noise.
0 to -28 dB
-6 dB
TRANSDUCER INTERFACE
RINGER
Ref
0/+8dB
and V
Analog Domain
6.37 dB
Trans-
allows
Gain
mit
Bias
pins are situated on adjacent pins.
M
U
X
the
-6.1 dB or
-3.6 dB
Receiver
Auxiliary
Speaker
-12 dB
Phone
Driver
Driver
Driver
0 dB
Out
reduction
5 dB
5 dB
HSPKR +
HSPKR -
SPKR +
SPKR -
AUXout
AUXin
MIC+
M +
M -
External To Device
of
Transitter
microphone
Bias
MT9196
75
75
AUX input
H/F answer-
back mic
Speakerphone
(40
Ref
transmitted
34
Speaker
Receiver
Handset
to analog
(150 )
may only
nominal)
min)
7-139
Ref