General Description

The MAX748A/MAX763A are 3.3V-output CMOS, step down switching regulators. The MAX748A accepts inputs from 3.3V to 16V and delivers up to 500mA. The MAX763A accepts inputs between 3.3V and 11V and delivers up to 500mA. Typical efficiencies are 85 to 90. Quiescent supply current is 1.4mA (MAX763A), and only 0.2µA in shutdown.

Pulse-width-modulation (PWM) current-mode control provides precise output regulation and excellent transient responses. Output voltage accuracy is guaranteed to be ±5 over line, load, and temperature variations. Fixed-frequency switching allows easy filtering of output ripple and noise, as well as the use of small external components. A 22µH inductor works in most applications, so no magnetics design is necessary.

The MAX748A/MAX763A also feature cycle-by-cycle current limiting, overcurrent limiting, undervoltage lockout, and programmable soft-start protection. The MAX748A is available in 8-pin DIP and 16-pin wide SO packages; the MAX763A comes in 8-pin DIP and SO packages.

Features

♦ Up to 500mA Load Currents

♦ Guaranteed 159kHz to 219.5kHz Current-Mode PWM

♦ 85 to 90 Efficiencies

♦ 1.7mA Quiescent Current (MAX748A)

   1.4mA Quiescent Current (MAX763A)

♦ 0.2µA Shutdown Supply Current

♦ 22µH Preselected Inductor Value;

   No Component Design Required

♦ Overcurrent, Soft-Start, and Undervoltage

   Lockout Protection

♦ Cycle-by-Cycle Current Limiting

♦ 8-Pin DIP/SO Packages (MAX763A)

Applications

   5V-to-3.3V Converters

   Cellular Phones

   Portable Instruments

   Hand-Held Computers

   Computer Peripherals