GL6965
Description Functions
1. Line voltage increasing circuit (up)
The voltage of V
L,
V
CC
or V
REF
can be increased by connecting UP terminal to GND directly or
through the resistance.
The internal equivalent circuit is as shown in the figure.
(1) The voltage increased most up to about 1.5V in V
L
when UP terminal is directly connected to
GND. when the resistance is inserted the voltage increases according to the resistance value.
(See graph)
(2) In case of usage with MUTE terminal connected, the line voltage can be increased only at
muting.
(3) Avoid impressing the voltage over V
CC
or under GND.
(4) When not in use, make the circuit opened or connected to V
CC.
Internal equivalent circuit
PIN20 (V
CC
)
10k
5k
1.5
PIN20 (UP)
l
UP
2
. Side tone protection circuit (Balancing circuit)
The time constant (hereafter referred to as BN constant) of the side tone protection circuit in the
example of application circuit is adjusted nearly to 0.4φ 7dB. Since the side tone characteristic
varies according to this BN time constant, adjust the time constant confirming to the function of the
telephone set.
EXAMPLE OF BN TIME CONSTANT
6.2 k§
Ù
10 kΩ
2.0 k§
Ù
0.015µF
In case of 0.5
φ
7dB is determined
to be the center.
13
HYNIX [ HYNIX SEMICONDUCTOR ]
