50ms/div
V
OUT
= 3.3V, C
OUT
= 0pF, R
L
= 2kΩ
TIMING RELATIONSHIPS
V
IN
V
OUT
POWER FAIL
STBY
12
( )
(
)
( 1)
( LBO)
SW1
(
)
(
)
POWER FAIL (LBO
1) 50ms ( 2)
(house
keeping) LBO
C1 R3 STBY
(1.15V) IC
IC1 350mV
150mA
10µA 11.5V
EDN 3/16/95
POWER FAIL
S1
7
3, 6
V
IN
C1
1µF
R2
1M
R1
1k
R3
220k
GND V
REF
STBY
1 LBO
SET 2
LBI
OUT
8
LOW-BATTERY
COMPARATOR
ERROR
AMPLIFIER
R4
1M, 0.1%
R5
49.9k, 0.1%
R6
604k, 0.1%
IN
5
4
V
OUT
3.3V
IC1
MAX882
DESIGN SHOWCASE
1
S1
2 1
3