MIC4680_08 Datasheet, PDF (1/15 Pages) Micrel Semiconductor – 1A 200kHz SuperSwitcher Buck Regulator

MIC4680
1A 200kHz SuperSwitcher™
Buck Regulator
General Description
The MIC4680 SuperSwitcher™ is an easy-to-use fixed or
adjustable output voltage step-down (buck) switch-mode
voltage regulator. The 200kHz MIC4680 achieves up to
1.3A of continuous output current over a wide input range
in a 8-pin SOIC.
The MIC4680 is available in 3.3V and 5V fixed output
versions or adjustable output down to 1.25V.
The MIC4680 has an input voltage range of 4V to 34V,
with excellent line, load, and transient response. The
regulator performs cycle-by-cycle current limiting and
thermal shutdown for protection under fault conditions. In
shutdown mode, the regulator draws less than 2µA of
standby current.
The MIC4680 SuperSwitcher™ regulator requires a mini-
mum number of external components and can operate
using a standard series of inductors and capacitors.
Frequency compensation is provided internally for fast
transient response and ease of use.
The MIC4680 is available in the 8-pin SOIC with a
–40°C to +125°C junction temperature range.
Features
• SOIC-8 package with up to 1.3A output current
• All surface mount solution
• Only 4 external components required
• Fixed 200kHz operation
• 3.3V, 5V, and adjustable output versions
• Internally compensated with fast transient response
• Wide 4V to 34V operating input voltage range
• Less than 2µA typical shutdown-mode current
• Up to 90% efficiency
• Thermal shutdown
• Overcurrent protection
Applications
• Simple 1A high-efficiency step-down (buck) regulator
• Replacement of TO-220 and TO-263 designs
• Efficient pre-regulator (5V to 2.5V, 12V to 3.3V, etc.)
• On-card switching regulators
• Positive-to-negative converter (inverting buck-boost)
• Simple battery charger
• Negative boost converter
• Higher output current regulator using external FET
Typical Application
+6V to +34V
SHUTDOWN
ENABLE
C1
15µF
35V
Power
SOIC-8
MIC4680-3.3BM
2 _IN
SW ³
1 _SHDN
FB ⁴
GND
5–8
L1
68µH
D1
B260A or
SS26
3.3V/1A
C2
220µF
16V
+5V to +34V
SHUTDOWN
ENABLE
C1
15µF
35V
Power
SOIC-8
MIC4680BM
2 _IN
SW ³
1 _SHDN
FB ⁴
GND
5–8
L1
68µH
D1
B260A or
SS26
R1
3.01k
R2
2.94k
2.5V/1A
C2
220µF
16V
Fixed Regulator Circuit
Adjustable Regulator Circuit
SuperSwitcher is a trademark of Micrel, Inc.
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel [phone] • fax + 1 [phone] • http://www.micrel.com
March 2008
M9999-032808