MIC4681 Datasheet, PDF (1/19 Pages) Micrel Semiconductor – 2A-Peak SuperSwitcher™ SOP-8 Buck Regulator

MIC4681
Micrel
MIC4681
2A-Peak SuperSwitcher™ SOP-8 Buck Regulator
Final Information
General Description
The MIC4681 SuperSwitcher™ is an easy-to-use step-down
(buck) voltage-mode switching regulator. The 200kHz
MIC4681 achieves over 1A of continuous output current over
a 4V to 30V input range in an 8-lead SOPpackage . The
MIC4681 features a high 2.1A minimum current limit, making
the device ideal for pulsed current applications such as GSM
and TDMA cell phone battery chargers and power supplies.
The MIC4681 sustains an output of 4.2V/2A within a typical
GSM charging environment.
The MIC4681 has an input voltage range of 4V to 30V, with
excellent line, load, and transient response. The regulator
performs cycle-by-cycle current limiting and thermal shut-
down for protection under fault conditions. In shutdown
mode, the regulator draws less than 6µA of standby current.
The MIC4681 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 re-
sponse and ease of use.
The MIC4681 is available in the 8-lead SOP with a
–40°C to +125°C junction temperature range.
Features
• SO-8 package with over 1A continuous output current
• Capable of 2A pulse charging for GSM applications
• All surface mount solution
• Only 4 external components required
• Fixed 200kHz operation
• Output adjustable down to 1.25V
• Internally compensated with fast transient response
• Wide 4V to 30V operating input voltage range
• Less than 6µA typical shutdown-mode current
• Up to 90% efficiency
• Thermal shutdown
• Overcurrent protection
Applications
• Cellular phone battery charger
• Cellular phone power supply
• Simple 1A continuous high-efficiency step-down (buck)
regulator
• Replacement of a TO-220 and TO-263 designs
• Positive-to-negative converter (inverting buck-boost)
• Negative boost converter
• Higher output current regulator using external FET
Typical Applications
+5V to +30V
SHUTDOWN
ENABLE
C1
22µF
35V
Power
SOP-8
MIC4681BM
2 _IN
SW ³
1 _SHDN
FB ⁴
GND
5–8
L1
68µH
D1
B340A or
SS36
R1
3.01k
R2
2.94k
2.5V/1A
C2
220µF
10V
Adjustable Regulator Circuit
SuperSwitcher is a trademark of Micrel, Inc.
Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 [phone] • fax + 1 [phone] • http://www.micrel.com
February 2001
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MIC4681