LM2757,pdf datasheet ( Switche

The LM2757 is a constant frequency pre-regulated switched-capacitor charge pump that operates at 1.25 MHz to produce a low-noise regulated output voltage. The device can be configured to provide up to 100 mA at 4.1V, 110 mA at 4.5V, or 180 mA at 5V. Excellent efficiency is achieved without the use of an inductor by operating the charge pump in a gain of either 3/2 or 2 according to the input voltage and output voltage option selection.

The LM2757 presents a high impedance at the V_OUT pin when shut down. This allows for use in applications that require the regulated output bus to be driven by another supply while the LM2757 is shut down.

A perfect fit for space-constrained, battery-operated applications, the LM2757 requires only 4 small, inexpensive ceramic capacitors. LM2757 is a tiny 1.2 mm X 1.6 mm 12–bump micro SMD device. Built in soft-start, over-current protection, and thermal shutdown features are also included in this device.