Features

• Up to 96% Efficiency
• True Output Load Disconnect
• Inrush Current Limiting and Internal Soft-Start
• Low Voltage Start-Up: 0.85V
• Automatic Burst Mode® Operation with IQ ~ 20µA
• Continuous Switching at Light Loads (LTC3429B)
• Internal Synchronous Rectifier
• Current Mode Control with Internal Compensation
• Short-Circuit Protection
• 500kHz Fixed Frequency Switching
• Input Range: 0.5V to 4.4V
• Output Range: 2.5V to 4.3V (Up to 5V with Schottky)
• Shutdown Current: <1µA
• Antiringing Control Minimizes EMI
• Tiny External Components
• Low Profile (1mm) SOT-23 Package

Typical Application

Description

The LTC3429/LTC3429B are high efficiency synchronous, fixed frequency, step-up DC/DC converters with true output load disconnect, inrush current limiting and softstart in a low profile 6-lead ThinSOT package. These devices are capable of supplying 100mA from a single AA cell input or 250mA from a 2-cell AA with a 3.3V output.

A switching frequency of 500kHz minimizes overall solution footprint by allowing the use of tiny, low profile inductors and ceramic capacitors. Current mode PWM control with internal compensation reduces external parts count thereby saving critical board real estate. The LTC3429 shifts automatically to power saving Burst Mode operation at light loads while the LTC3429B features continuous switching at light loads. Antiringing control circuitry reduces EMI concerns by damping the inductor in discontinuous mode.

The devices also feature low shutdown current of under 1µA. The true output disconnect feature allows the output to be completely discharged in shutdown. It also limits the inrush of current during start-up, minimizing surge currents seen by the input supply.