Datasheet

11
LTC1751/LTC1751-3.3/LTC1751-5
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-
tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
TYPICAL APPLICATIO S
U
1751 TA04
1µF
LTC1751-5
C
+
C
–
V
OUT
GND
V
IN
SHDN
SS
2
65
1
4
3
7
8
PGOOD
V
OUT
= 5V
PGOOD
10µF10µF
1nF
1Ω
100k
1751 TA05
1µF
LTC1751-5
C
+
C
–
V
OUT
GND
V
IN
SHDN
SS
2
65
1
4
3
7
8
PGOOD
10µF10µF10µF
75k
V
OUT
= 5V
I
OUT
≤ 100mA
HIGH = BACKUP MODE
100k
+
–
1
2
3
4
5
6
7
8
+
+
+
3-CELL
NiCd
BATTERY
330pF
1.43M
475k
IN4148
BAT54C
LTC1540
Si4435DY
V
IN
= 5V
10k
1M
HYST
1751 TA07
C
+
C
–
V
OUT
GND
V
IN
SHDN
SS
2
65
1
4
3
7
8
FB
10µF10µF
1µF
R
X
ON
OFF
I
L
=
1.205V
R
X
LOAD
V
OUT
≤ 2 V
IN
V
IN
LTC1751
USB Port to Regulated 5V Power Supply with Soft-Start
Low Power Battery Backup with Auto Switchover and No Reverse Current
2-Cell NiCd or NiMH to 3.3V with Low Standby Current
Boosted Constant Current Source
1751 TA06
1µF
LTC1751-3.3
C
+
C
–
V
OUT
GND
V
IN
SHDN
SS
2
65
1
4
3
7
8
PGOOD
3.3V
40mA
PGOOD
10µF10µF
1nF
100k
ON
OFF
2-CELL
NiCd OR
NiMH
+
+