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MIC4576_06 Datasheet, PDF (1/8 Pages) Micrel Semiconductor – 200kHz Simple 3A Buck Regulator | |||
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MIC4576
MIC4576
Micrel, Inc.
200kHz Simple 3A Buck Regulator
General Description
The MIC4576 is a series of easy to use ï¬xed and adjustable
BiCMOS step-down (buck) switch-mode voltage regulators.
The 200kHz MIC4576 duplicates the pinout and function of
the 52kHz LM2576. The higher switching frequency may
allow up to a 2:1 reduction in output ï¬lter inductor size.
The MIC4576 is available in 3.3V, and 5V ï¬xed output ver-
sions or a 1.23V to 33V adjustable output version. Both
versions are capable of driving a 3A load with excellent line
and load regulation.
The feedback voltage is guaranteed to ±2% tolerance for
adjustable versions, and the output voltage is guaranteed to
±3% for ï¬xed versions, within speciï¬ed voltages and load con-
ditions. The oscillator frequency is guaranteed to ±10%.
In shutdown mode, the regulator draws less than 200µA
standby current. The regulator performs cycle-by-cycle
current limiting and thermal shutdown for protection under
fault conditions.
This series of simple switch-mode regulators requires a mini-
mum number of external components and can operate using
a standard series of inductors. Frequency compensation is
provided internally.
The MIC4576 is available in TO-220 (T) and TO-263 (U)
packages for the industrial temperature range.
Features
⢠Fixed 200kHz operation
⢠3.3V, 5V, and adjustable output versions
⢠Voltage over speciï¬ed line and load conditions:
Fixed version: ±3% max. output voltage
Adjustable version: ±2% max. feedback voltage
⢠Guaranteed 3A switch current
⢠Wide 4V to 36V input voltage range
⢠Wide 1.23V to 33V output voltage range
⢠Requires minimum external components
⢠< 200µA typical shutdown mode
⢠75% efï¬ciency (adjustable version > 75% typical)
⢠Standard inductors are 25% of typical LM2576 values
⢠Thermal shutdown
⢠Overcurrent protection
⢠100% electrical thermal limit burn-in
Applications
⢠Simple high-efï¬ciency step-down (buck) regulator
⢠Efï¬cient preregulator for linear regulators
⢠On-card switching regulators
⢠Positive-to-negative converter (inverting buck-boost)
⢠Battery Charger
⢠Negative boost converter
⢠Step-down to 3.3V for Intel Pentiumâ¢
and similar microprocessors
Typical Applications
Shutdown
Enable
8V to 36V
C1
470µF
63V
5 SHDN
SW 2
MIC4576-5.0WT
1 VIN
FB 4
GND
3
L1
33µH
D1
MBR360
5V/3A
C2
1000µF
16V
Fixed Regulator
Shutdown
Enable
16V to 36V
C1
470µF
63V
5 SHDN
SW 2
1
MIC4576WT
VIN
FB
4
GND
3
L1
68µH
MBR360
12V/3A
R2
13.0k
1%
R1
1.50k
1%
C2
1000µF
16V
Adjustable Regulator
Micrel, Inc. ⢠2180 Fortune Drive ⢠San Jose, CA 95131 ⢠USA ⢠tel + 1 (408) 944-0800 ⢠fax + 1 (408) 474-1000 ⢠http://www.micrel.com
March 2006
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MIC4576
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