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