The MAX1626/MAX1627 step-down DC-DC switching controllers provide high efficiency over loads ranging from 1mA to more than 2A. A unique current-limited, pulse-frequency-modulated (PFM) control scheme operates with up to a 100% duty cycle, resulting in very low dropout voltages. This control scheme eliminates minimum load requirements and reduces the supply current under light loads to 90µA (versus 2mA to 10mA for common pulse-width modulation controllers).
These step-down controllers drive an external P-channel MOSFET, allowing design flexibility for applications to 12W or higher. Soft-start reduces current surges during start-up. A high switching frequency (up to 300kHz) and operation in continuous-conduction mode allow the use of tiny surface-mount inductors. Output capacitor requirements are also reduced, minimizing PC board area and system costs.
The output voltage is preset at 5V or 3.3V for the MAX1626 and adjustable for the MAX1627. Input voltages can be up to 16.5V. The MAX1626/MAX1627 are functional upgrades for the MAX1649/MAX1651.
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