LTC3251 - 500mA High Efficiency, Low Noise, Inductorless Step-Down DC/DC Converters

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.

Features
  • 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
Typical Application

Applications
  • Handheld Devices
  • Cellular Phones
  • Portable Electronic Equipment
  • DSP Power Supplies
Packaging

Order Information
Part NumberPackageTempPrice(1-99)Price (1k)*
LTC3251EMSE-1.2#PBFMS-10EE$2.79$1.95
LTC3251EMSE-1.2#TRPBFMS-10EE$2.01
LTC3251EMSE-1.5#PBFMS-10EE$2.79$1.95
LTC3251EMSE-1.5#TRPBFMS-10EE$2.01
LTC3251EMSE#PBFMS-10EE$2.79$1.95
LTC3251EMSE#TRPBFMS-10EE$2.01
Demo Boards
Part NumberDescriptionPrice
DC506ALTC3251EMSE Demo Board | Spread-Spectrum, Low Noise, Inductorless Step-Down Charge Pump, 3.2V ≤ VIN ≤ 5.5V, Vout @ Up to 500mA$75.00
Datasheet
Design Note
Reliability Data
Related Product
LTC3251/LTC3251-1.2/LTC3251-1.5 - 500mA High Efficiency, Low Noise, Inductorless Step-Down DC/DC Converters
LTC3251 Package Drawing LTC3251
DN310 New Step-Down Charge Pumps are Tiny, Efficient and Very Low Noise
R415 - Reliability Data
LTC3251 Footprints and Symbols