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Electronic Volume Controller IC
PT2256V
INITIALIZATION WHEN POWER ON
PT2256V has an auto-initialization function during the Power On period. When Power is turned ON, the
volume level is set to the initial value of -46 dB by setting the RST pin to “L” level. Please refer to the
diagram below.
VDD
VDD
VIL
/RST
0V
T≥1ms
T
BACK UP WHEN POWER OFF
When the /INH Pin is set at “L” Level, all input and output pins are disabled and the current
consumption is reduced to the minimum. Under this condition, the backup becomes possible. Please
refer to the diagram below:
VDD
VDD
Backu p
4.5V
VD D min > 4.5V
Backu p D ata is lost
0V
Backu p Mod e
No rmal Mode
No rmal M ode
The backup circuit is given below:
10 K
IN4 001
10 K
VDD
51 K
VDD
VSS
/INH
PT225 6V
+
1 000 µF/16 V
-
VSS
Notes:
1. If the VDD drops from 11V to 4.5V, then the backup is possible for a period of 6 days. However, if
VDD-Vss drops below 4.5V, the backup becomes impossible.
PT2256V V1.2
- 6 -
August, 2006
PTC [ PRINCETON TECHNOLOGY CORP ]
