5 Functional Description

The MCP16367/8/9 is a high input voltage step-down regulator, capable of supplying 400 mA to a regulated output voltage from 2.0V to 24V. Internally, the trimmed 2.2 MHz oscillator provides a fixed frequency, while the Peak Current Mode Control architecture varies the duty cycle for output voltage regulation. An internal floating driver is used to turn the high-side integrated N-Channel MOSFET on and off. The power for this driver is derived from an external bootstrap capacitor whose energy is supplied from a fixed voltage ranging between 3.0V and 5.5V, typically the input or output voltage of the converter. For applications with an output voltage outside of this range, 12V for example, the bootstrap capacitor bias can be derived from the output using a simple Zener diode regulator.