3.3V / Step-Down / Current-Mode PWM DC-DC Converters - Maxim
Description
19-0190; Rev 0; 9/93
3.
3V, Step-Down, Current-Mode PWM DC-DC Converters
__________________General Description
The MAX748A/MAX763A are 3.
3V-output CMOS, stepdown 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
o Up to 500mA Load Currents o Guaranteed 159kHz to 219.
5kHz Current-Mode PWM o 85% to 90% Efficiencies o 1.
7mA Quiescent Current (MAX748A) 1.
4mA Quiescent Current (MAX763A) o 0.
2µA Shutdown Supply Current o 22µH Preselected Inductor Value; No Component Design Required o Overcurrent, Soft-Start, and Undervoltage Lockout Protection o Cycle-by-Cycle Current Limiting o 8-Pin DIP/SO Packages (MAX763A)
MAX748A/MAX763A
_________________Ordering Information
PART MAX748ACPA MAX748ACWE MAX748AC/D MAX748AEPA MAX748AEWE MAX748AMJA TEMP.
RANGE 0°C to +70°C 0°C to +70°C 0°C to +70°C -40°C to +85°C -40°C to +85°C -55°C to +125°C PIN-PACKAGE 8 Plastic DIP 16 Wide SO Dice* 8 Plastic DIP 16 Wide SO 8 CERDIP
___________________________Applications
5V-to-3.
3V Converters Cellular Phones Portable Instruments Hand-Held Computers Computer Periph...
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