Rainbow Electronics DS1680 - Manual (Page 9)

DS1680
9 of 23
POWER-FAIL COMPARATOR Figure 6
DS1680
V
CC
GND
PFO
PFI
+5V
C1
R1
VIN
R2 R3
to µP
V
TRIP
= 1.25 V
H
= 1.25 /
R2||R3
R1 + R2||R3
R1 + R2
R2
V
I
– 1.25
R1
+
5 - 1.25
R3
=
1.25
R2