Datasheet

DS1231/S
022698 6/9
APPLICATION WITH MODE PIN GROUNDED Figure 6
IN
MODE
TOL
GND
V
CC
NMI
RST
RST
TO µ P
DS1231
+5V
DC
VOLTAGE SENSE POINT
EXAMPLE: CTR = 0.2 IC = 30 µA IF = 150 µA
VOLTAGE SENSE POINT = 105 AND
VZ = 100 VOLTS
IC
R1
IF
-5% V
CC
THRESHOLD
VOLTAGE SENSE POINT (TRIP VALUE)  VZ 
IC
CTR
XR1
CTR 
IC
IF
CTR  CURRENT TRANSFER RATIO
VZ  ZENNER VOLTAGE
THEN 105  100 
30
0.2
xR1 R133K
NOTE: RST
requires a pull–up resister.
AC VOLTAGE MONITOR WITH OPTO-ISOLATION Figure 7
IN
MODE
TOL
GND
V
CC
NMI
RST
RST
-5% V
CC
THRESHOLD
TO µ P
DS1231
+5V
DC
AC LINE
INPUT
NOTE: RST requires a pull–up resister.