Switching Regulator. MIC2171 Datasheet

MIC2171 Regulator. Datasheet pdf. Equivalent

Part MIC2171
Description 100kHz 2.5A Switching Regulator
Feature MIC2171 100kHz 2.5A Switching Regulator General Description The MIC2171 is a complete 100kHz SMPS c.
Manufacture Micrel Semiconductor
Datasheet
Download MIC2171 Datasheet



MIC2171
MIC2171
100kHz 2.5A Switching Regulator
General Description
The MIC2171 is a complete 100kHz SMPS current-mode
controller with an internal 65V 2.5A power switch.
Although primarily intended for voltage step-up applica-
tions, the floating switch architecture of the MIC2171
makes it practical for step-down, inverting, and Cuk config-
urations as well as isolated topologies.
Operating from 3V to 40V, the MIC2171 draws only 7mA
of quiescent current, making it attractive for battery
operated supplies.
The MIC2171 is available in a 5-pin TO-220 or TO-263 for
–40°C to +85°C operation.
Data sheets and support documentation can be found on
Micrel’s web site at: www.micrel.com.
Features
2.5A, 65V internal switch rating
3V to 40V input voltage range
Current-mode operation, 2.5A peak
Internal cycle-by-cycle current limit
Thermal shutdown
Twice the frequency of the LM2577
Low external parts count
Operates in most switching topologies
7mA quiescent current (operating)
Fits LT1171/LM2577 TO-220 and TO-263 sockets
Applications
Laptop/palmtop computers
Battery operated equipment
Hand-held instruments
Off-line converter up to 50W(requires external power
switch)
Pre-driver for higher power capability
___________________________________________________________________________________________________________
Typical Application
+5V
(4.75V min.)
L1
15µH
C1*
47µF
IN
SW
MIC2171
D1
1N5822
VO U T
+12V, 0.25A
R1
10.7k
1%
COMP
R3
1k
GND
C3
1µF
FB
C2
470µF
R2
1.24k
1%
* Locate near MIC2171 when supply leads > 2”
Figure 1. MIC2171 5V to 12V Boost Converter
VIN
4V to 6V
C1
47µF
R4*
IN
SW
MIC2171
COMP
R3
1k
GND
C2
1µF
FB
VOU T
T1 5V, 0.5A
C3*
D1*
D2
1N5818
C4
470µF
R1
3.74k
1%
1:1.25
LP RI = 12µH
R2
1.24k
1%
* Optional voltage clipper (may be req’d if T1 leakage inductance too high)
Figure 2. MIC2171 5VFlyback Converter
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
May 2007
1 M9999-051107



MIC2171
Micrel, Inc.
Ordering Information
Part Number
Standard
RoHS Compliant*
Temperature Range
MIC2171BT
MIC2171WT
–40° to +85°C
MIC2171BU
MIC2171WU
–40° to +85°C
*RoHS compliant with "high-melting solder" exemption.
Package
5-Pin TO-220
5-Pin TO-263
MIC2171
Pin Configuration
Tab GND
5 IN
4 SW
3 GND
2 FB
1 COMP
5-Pin TO-220 (T)
Tab GND
5 IN
4 SW
3 GND
2 FB
1 COMP
5-Pin TO-263 (U)
Pin Description
Pin Number
1
2
3
4
5
Pin Name
COMP
FB
GND
SW
IN
Pin Function
Frequency Compensation: Output of transconductance-type error amplifier.
Primary function is for loop stabilization. Can also be used for output voltage
soft-start and current limit tailoring.
Feedback: Inverting input of error amplifier. Connect to external resistive divider
to set power supply output voltage.
Ground: Connect directly to the input filter capacitor for proper operation (see
applications info).
Power Switch Collector: Collector of NPN switch. Connect to external inductor
or input voltage depending on circuit topology.
Supply Voltage: 3.0V to 40V
May 2007
2 M9999-051107





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