MIC4681
Micrel
MIC4681
2A-Peak SuperSwitcher™ SOP-8 Buck Regulator
Final Information
General Description
Features
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.
• 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
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.
• Thermal shutdown
• Overcurrent protection
Applications
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.
• 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
The MIC4681 is available in the 8-lead SOP with a
–40°C to +125°C junction temperature range.
• Higher output current regulator using external FET
Typical Applications
MIC4681BM
L1
+5V to +30V
2.5V/1A
2
1
3
4
IN
SW
C1
22µF
68µH
R1
C2
220µF
10V
3.01k
35V
SHUTDOWN
ENABLE
SHDN
FB
D1
R2
2.94k
GND
5–8
B340A or
SS36
Power
SOP-8
Adjustable Regulator Circuit
SuperSwitcher is a trademark of Micrel, Inc.
Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 944-0970 • http://www.micrel.com
February 2001
1
MIC4681