General Description
The Micrel MIC2177 is a 200kHz synchronous buck (step down) switching regulator designed for high-efficiency, battery-powered applications.
The MIC2177 operates from a 4.5V to 16.5V input and features internal power MOSFETs that can supply up to 2.5A output current. It can operate with a maximum duty cycle of 100% for use in low-dropout conditions. It also features a shutdown mode that reduces quiescent current to less than 5µA.

Features
• 4.5V to 16.5V input voltage range
• Dual-mode operation for high efficiency (up to 96%
   –  PWM mode for > 200mA load current
   –  Skip mode for < 200mA load current
•100mΩinternal power MOSFETs at 12V input
• 200kHz preset switching frequency
• Low quiescent current
   –  1.0mA in PWM mode
   –  500µA in skip mode
   –  < 5µA in shutdown mode
• 100% duty cycle for low dropout operation
• Current-mode control
   –  Simplified loop compensation
   –  Superior line regulation
• Current limit
• Thermal shutdown
• Undervoltage lockout

Applications
• High-efficiency, battery-powered supplies
• Buck (step-down) dc-to-dc converters
• Cellular telephones
• Laptop computers
• Hand-held instruments
• Battery Charger