TFB3869 Datasheet, PDF (14/14 Pages) Gunter Seniconductor GmbH. – Subscriber Line Interface Circuit (SLIC)

Ground Key Detection
For ground key detection the LA or LB outputs have to be connected to ground.
In this case the voltage drop on an internal differential amplifier reaches 1 V in minimum for switching the ET
output from high to low.
Protection Circuit
GND
< 1n
13
GND
8
LB
a
< 1n
TFB 3869 T
11
LA
b
VBAT
10
VBAT