View mic9131 datasheet:

MIC9131 Micrel MIC9131 High-Voltage, High-Speed Telecom DC-to-DC Controller Final Information General Description Features The MIC9131 is a current-mode PWM controller that effi- • Input voltages up to 180V ciently converts –48V telecom voltages to logic levels. The • Internal oscillator capable of > 2.5MHz operation MIC9131 features a high voltage start-up circuit that allows • Accurate 75% maximum duty cycle the device to be connected to input voltages as high as 180V. • Synchronisation capability to 6MHz The high input voltage capability protects the MIC9131 from • Current sense delay of 34ns line transients that are common in telecom systems. The • Minimum pulse width of <25ns start-up circuitry also saves valuable board space and simpli- • 90% efficiency fies designs by in