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.

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