LTC3251

` 500mA Output Current
` No Inductors
` 2.7V to 5.5V Input Voltage Range
` Typical Efficiency 50% Higher Than LDOs
` 2-Phase, Spread Spectrum Operation for Low Input and Output Noise
` Shutdown Disconnects Load from V_IN
` Adjustable Output Voltage Range: 0.9V to 1.6V
` Super Burst, Burst and Burst Defeat Operation
` Low Operating Current: I<sub>IN</sub> = 35A (Burst Mode<sup>®</sup> Operation)
` Super Burst Operating Current: I_IN = 8A
` Low Shutdown Current: I<sub>IN</sub> = 0.01A Typ
` Soft-Start Limits Inrush Current at Turn-On
` Short-Circuit and Overtemperature Protected
` Available in a Thermally Enhanced 10-Pin MSOP Package

· Handheld Devices
· Cellular Phones
· Portable Electronic Equipment
· DSP Power Supplies

V_IN to GND ........................................................ 0.3V to 6V
MD0, MD1 and FB to GND .................. 0.3V to (V_IN + 0.3V)
I_OUT (Note 2) ............................................................ 650mA
Operating Temperature Range (Note 3) ... 40°C to 85°C
Storage Temperature Range .................. 65°C to 150°C
Lead Temperature (Soldering, 10 sec)...................... 300°C

The LTC^®3251 is a 2-phase charge pump step-down DC/DC converter that produces a regulated output from a 2.7V to 5.5V input. The part uses switched capacitor fractional conversion to achieve a typical efficiency increase of 50% over that of a linear regulator. No inductorsare required. VOUT is resistor programmable from 0.9V to 1.6V with up to 500mA of load current

A unique 2-phase spread spectrum architecture of LTC3251 provides a very low noise regulated output as well as low noise at theinput. The part has four operating modes: Continuous Spread Spectrum, Spread Spectrum with Burst Mode operation, Super BurstTM mode operation and shutdown.

Low operating current (35mA in Burst Mode operation, 8mAin Super Burst mode operation) and low external parts count (five small ceramic capacitors and two resistors) make the LTC3251 ideally suited for space-constrainedbattery-powered applications. The part is short-circuit andovertemperature protected, and is available in a thermally enhanced 10-pin MSOP package.