MIC2245
4MHz PWM Synchronous Buck
Regulator with LDO Standby Mode General Description Features The Micrel MIC2245 is a high efficiency 4MHz pulse
width modulated (PWM) synchronous buck (stepdown) regulator that features a LOWQв„ў LDO
standby mode that draws only 18ВµA 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 LOWQв„ў mode, the LDO maintains the output
voltage and draws only 18ВµA 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 …