Features

• Programmable Average Input Current Limit
• 5% Input Current Accuracy
• 200mA to 1000mA Program Range
• V_IN: 1.8V to 5.5V, V_OUT: 2V to 5.25V
• Supports High Current GSM/GPRS Load Burst
• V_IN > V_OUT Operation
• 1.6MHz Fixed Frequency Operation
• Internal Current Sense Resistor
• 1.2A Peak Current Limit
• Up to 93% Efficiency
• Output Disconnect in Shutdown
• Soft-Start
• Low Quiescent Current Burst Mode® Operation (15μA)
• Available in 2mm × 3mm × 0.75mm DFN Package

Typical Application

Description

The LTC3125 is a high efficiency, synchronous step-up DC/DC converter with an accurate programmable average input current limit. The resistor programmable average input current limit is 5% accurate at 500mA and is suitable for a wide variety of applications. In mobile computing, GSM and GPRS cards demand high current pulses well beyond the capability of the PC Card and CompactFlash slots. The LTC3125 in concert with a reservoir capacitor, keeps the slot power safely within its capabilities providing a high performance and simple solution.

Synchronous rectification produces high efficiency while the 1.6MHz switching frequency minimizes the solution footprint. The current mode PWM design is internally compensated. Output disconnect allows the load to discharge in shutdown, while also providing inrush current limiting.

Other features include a <1μA shutdown current, short circuit and thermal overload protection. The LTC3125 is offered in a low profile 0.75mm × 2mm × 3mm package.