Digital Line to POTS Interface
CMX605
CMX605
D4/P3
Pin No.
11
Signal
Description
Name
V
BIAS
Type
O/P
An internally generated bias voltage of V
DD
/2,
except when the device has been reset, V
BIAS
will discharge to V
SS.
It should be decoupled to
V
SS
by a capacitor mounted close to the device
pins.
The input to the DTMF decoder, internally
biased at V
DD
/2. It should be ac coupled.
The inverting input to the uncommitted
amplifier.
The output of the uncommitted amplifier.
The squarewave output of the Ringing Signal
generator.
The positive supply rail. Levels and thresholds
within the device are proportional to this
voltage. It should be decoupled to V
SS
by a
capacitor mounted close to the device pins.
12
RXIN
I/P
13
OPNIN
I/P
14
15
OPOUT
RING
O/P
O/P
16
V
DD
Power
Notes:
I/P
O/P
T/S
=
=
=
Input
Output
3-state Output
This device is capable of detecting and decoding small amplitude signals. To achieve this V
DD
and V
BIAS
decoupling and protecting the receive path from extraneous in-band signals are very
important. It is recommended that the printed circuit board is laid out with a ground plane in the
CMX605 area to provide a low impedance connection between the V
SS
pin and the V
DD
and
V
BIAS
decoupling capacitors.
©
2001 Consumer Microcircuits Limited
5
D/605/6
CMLMICRO [ CML MICROCIRCUITS ]
