U3761MB-T Datasheet, PDF (8/27 Pages) ATMEL Corporation – Universal Telephone IC - All Functions Integrated

Pin Description
Pin Symbol Function
27
THA Ringer threshold adjustment
Configuration
VRIAC
140K
12K
1V
THA
6V
20K
6V
PD
The range of transmit and receive gain variations between
28
AGC
short and long loops may be adjusted by connecting a
resistor R_AGC from this pin to (GND). This pin can be left
open to set AGC out of action.
AGC
RDC
VL
PD
PD
29
VRIAC Ringing supply
VRIAC
70K
50 V
10K
PD
VRING
30
VRING
DC supply voltage for the tone ringer is limited to 30 V with
integrated Z-diode.
30 V
6.5K
200
PD
OUT
50 V
PD
31
RCK RC clock oscillator for ringer
3.4 V
RCK
6V
6V
PD
0.8 V
8 U3761MB-T
4744A–CORD–09/03