Features and Benefits
- Up to 500mA Output Current
- No Inductors
- 2.7V to 5.5V Input Voltage Range
- 2x Efficiency Improvement Over LDOs
- 2-Phase, Spread Spectrum Operation for Low Input and Output Noise
- Shutdown Disconnects Load from VIN
- Adjustable Output Voltage Range: 0.9V to 1.6V
- Fixed Output Voltages: 1.2V, 1.5V
- Super Burst, Burst and Burst Defeat Operating Modes
- Low Operating Current: IIN = 35µA (Burst Mode® Operation)
- Super Burst Operating Current: IIN = 10µA
- Low Shutdown Current: IIN = 0.01µA Typ
- Soft-Start Limits Inrush Current at Turn-On
- Short-Circuit and Overtemperature Protected
- Available in a Thermally Enhanced 10-Pin MSOP Package
The LTC3251/LTC3251-1.2/LTC3251-1.5 are 2-phase charge pump step-down DC/DC converters that produce a regulated output from a 2.7V to 5.5V input. The parts use switched capacitor fractional conversion to achieve twice the typical efficiency of a linear regulator. No inductors are required. VOUT is resistor programmable from 0.9V to 1.6V or fixed at 1.2V or 1.5V, with up to 500mA of load current available.
A unique 2-phase spread spectrum architecture provides a very low noise regulated output as well as low noise at the input. The parts have four operating modes: Continuous Spread Spectrum, Spread Spectrum with Burst Mode operation, Super Burst™ mode operation and shutdown.
Low operating current (35µA in Burst Mode operation, 10µA in Super Burst mode operation) and low external parts count make the LTC3251/LTC3251-1.2/LTC3251-1.5 ideally suited for space-constrained battery-powered applications. The parts are short-circuit and over-temperature protected, and are available in a thermally enhanced 10-pin MSOP package.
- Handheld Devices
- Cellular Phones
- Portable Electronic Equipment
- DSP Power Supplies
Product Lifecycle Production
At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.
Evaluation Kits (1)
Demonstration circuit 506A is a two-phase, step down charge pump DC/DC converter featuring the LTC3251EMSE. It produces a regulated 1.5V output voltage at up to 500mA of output current from a 3.2V to 5.5V input. The LTC3251's unique two-phase, spread spectrum architecture provides high efficient and low noise operation.
Tools & Simulations
LTspice® is a powerful, fast and free simulation software, schematic capture and waveform viewer with enhancements and models for improving the simulation of analog circuits.
Models for the following parts are available in LTspice:
Sample & Buy
The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.