• 2.7V to 5.5V supply/input voltage
• Light load LowQ® LDO mode
• 4MHz PWM mode
• Adjustable output voltage option down to 1V
• Ultra-fast transient response
• Uses a tiny 1µH inductor
• Fully integrated MOSFET switches
• Micropower shutdown operation
• Thermal shutdown and current limit protection
• -40°C to +125°C junction temperature range

The MIC2245 is a high efficiency 4MHz pulse width modulated (PWM) synchronous buck (stepdown) regulator that features a LowQ^® LDO standby mode that draws only 18µA of quiescent current. The MIC2245 allows an ultra-low noise, small size, and high efficiency solution for portable power applications.

In PWM mode, the MIC2245 operates with a constant frequency 4MHz PWM control. Under light load conditions, such as in system sleep or standby modes, the PWM switching operation can be disabled to reduce switching losses. In this light load LowQ^® mode, the LDO maintains the output voltage and draws only 18µA of quiescent current. The LDO mode of operation saves battery life while not introducing spurious noise and high ripple as experienced with pulse skipping or bursting mode regulators.

The MIC2245 operates from a 2.7V to 5.5V input voltage and features internal power MOSFETs that can supply up to 500mA output current in PWM mode. It can operate with a maximum duty cycle of 100% for use in low-dropout conditions.