MIC4575
200kHz Simple 1A Buck Regulator
General Description
Features
The MIC4575 is a series of easy to use fixed and
adjustable BiCMOS step-down (buck) switch-mode voltage
regulators. The 200kHz MIC4575 duplicates the pinout
and function of the 52kHz LM2575. The higher switching
frequency may allow up to a 2:1 reduction in output filter
inductor size.
• Fixed 200kHz operation
• 3.3V, 5V, and adjustable output versions
• Voltage over specified line and load conditions:
• Fixed version: ±3% max. output voltage
• Adjustable version: ±2% max. feedback voltage
• Guaranteed 1A switch current
• Wide 4V to 24V input voltage range
• Wide 1.23V to 20V output voltage range
• Requires minimum external components
• < 200µA typical shutdown mode
• 75% efficiency (adjustable version > 75% typical)
• Standard inductors and capacitors are25% of typical
LM2575 values
• Thermal shutdown
The MIC4575 is available in 3.3V, and 5V fixed output
versions or a 1.23V to 20V adjustable output version. Both
versions are capable of driving a 1A 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 fixed versions, within specified voltages and
load conditions. 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.
• Overcurrent protection
• 100% electrical thermal limit burn-in
Applications
This series of simple switch-mode regulators requires a
minimum number of external components and can operate
using a standard series of inductors. Frequency comp-
ensation is provided internally.
• Simple high-efficiency step-down (buck) regulator
• Efficient pre-regulator for linear regulators
• On-card switching regulators
• Positive-to-negative converter (inverting buck-boost)
• Battery charger
The MIC4575 is available in TO-220 (T) and TO-263 (U)
packages for the industrial temperature range.
Data sheets and support documentation can be found on
Micrel’s web site at www.micrel.com.
• Negative boost converter
• Step-down 6V to 3.3V for Intel Pentium® and similar
microprocessors
___________________________________________________________________________________________________________
Typical Application
L1
5.0V/1A
Shutdown
Enable
5
2
4
SHDN
MIC4575-5.0_T
VIN FB
SW
68µH
8V to 24V
1
C2
330µF
16V
C1
150µF
35V
GND
D1
1N5819
3
Fixed Regulator
Adjustable Regulator
Pentium is a registered trademark of Intel Corporation
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
M9999-072909
July 2009
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