MIC5157BN Micrel Inc, MIC5157BN Datasheet - Page 11
![IC CTRLR LDO REG SELECTBL 14-DIP](/photos/6/87/68706/576-14-dip_sml.jpg)
MIC5157BN
Manufacturer Part Number
MIC5157BN
Description
IC CTRLR LDO REG SELECTBL 14-DIP
Manufacturer
Micrel Inc
Type
Positive Fixedr
Datasheet
1.MIC5156YM.pdf
(13 pages)
Specifications of MIC5157BN
Number Of Outputs
1
Voltage - Output
3.3V, 5V, 12V
Current - Supply
4.5mA
Voltage - Input
3 ~ 36 V
Operating Temperature
-40°C ~ 85°C
Package / Case
14-DIP (0.300", 7.62mm)
Lead Free Status / RoHS Status
Contains lead / RoHS non-compliant
August 2005
MIC5156/5157/5158
Figure 5. Battery Charger Concept
E N
MIC5158
GND
V
DD
E A
G
D
S
R 1
R 2
V
IN
R 3
R 4
11
Uninterruptible Power Supply
The MIC5157 and two N-channel MOSFETs provide battery
switching for uninterruptible power as shown in figure (6).
Two MOSFETs are placed source-to-source to prevent cur-
rent flow through their body diodes when switched off. The
Super LDO regulator is continuously enabled to achieve
fast battery switch-in. Careful attention must be paid to the
ac-line monitoring circuitry to ensure that the output voltage
does not fall below design limits while the battery is being
switched in.
Line
Battery
A C
Line
Figure 6. UPS Power Supply Concept
EN
Power Supply
MIC5158
Off-line
GND
V
DD
1N4148
E A
G
D
S
Q1
Q2
G
G
D
S
S
D
40V max.
MOSFET body diodes
shown for clarity
MIC5156/5157/5158
Uninterruptable
D C
Micrel, Inc.