General Description

The MAX629 low-power DC-DC converter features an

internal N-channel MOSFET switch and programmable

current limiting. It is designed to supply positive or negative

bias voltages up to ±28V from input voltages in the

0.8V to VOUT range and can be configured for boost,

flyback, and SEPIC topologies.

The MAX629’s current-limited pulse-frequency-modulation

(PFM) control scheme provides high efficiency over a

wide range of load conditions. An internal, 0.5A N-channel

MOSFET switch reduces the total part count, and a

high switching frequency (up to 300kHz) allows for tiny

surface-mount magnetics.

The MAX629’s combination of low supply current, logiccontrolled

shutdown, small package, and tiny external

components makes it an extremely compact and efficient

high-voltage biasing solution that’s ideal for battery-powered

applications. The MAX629 is available in an 8-pin

SO package.

Applications

●● Positive or Negative LCD Bias Generators

●● High-Efficiency DC-DC Boost Converters

●● Varactor Tuning Diode Bias

●● Palmtop Computers

●● 2-Cell and 3-Cell Battery-Powered Applications

Features

●● Internal, 500mA, 28V N-Channel Switch

(No External FET Required)

●● Generates Positive or Negative Output Voltages

●● 80μA Supply Current

●● 1μA Max Shutdown Current

●● Up to 300kHz Switching Frequency

●● Adjustable Current Limit Allows Use of Small,

Inexpensive Inductors

●● 8-Pin SO Package