Date: 06/01/2009

Synchronous DC/DC converter with programmable input current limit

Linear Technology Corporation introduced the LTC3125, a 1.6MHz, current mode, synchronous boost DC/DC converter with an accurate and programmable average input current limit. Its internal 1.2A switches can deliver output voltages as high as 5.25V from an input voltage range of 1.8V to 5.5V, making it ideal for Li-Ion/Polymer, 3.3V PC card slot or multicell alkaline/NiMH applications. The LTC3125 can deliver up to 500mA of continuous output current (at 5V) from a 3.3V input.

The accurate adjustable current limit combined with an output reservoir capacitor makes the LTC3125 ideal for applications such as GSM and GPRS cards which demand 2A or higher current pulses from a power-limited input source. In addition, the LTC3125's accurate input current enables safe and fast charging of large Super or Ultra-capacitors in battery backup systems without overstressing the battery or auxiliary power source.
The LTC3125 can also operate in Buck mode, providing a regulated output lower than the input. Additional features include short-circuit protection, soft-start, and thermal protection.

Summary of other features:

1. 1.2A, 1.6MHz synchronous boost regulator offers output disconnect
2. Programmable average input current limit
3. 200mA to 1000mA IIN program range with 5% accuracy
4. Supports high current GSM/GPRS load bursts
5. VIN: 1.8V to 5.5V, VOUT: 2V to 5.25V
6. VIN > VOUT operation
7. 1.6MHz fixed frequency operation
8. Internal current sense resistor
9. 1.2A peak inductor current limit
10. Up to 93% efficiency
11. Soft-start
12. Low quiescent current burst mode operation: IQ=15uA

Packaging: DFN-8 Package
Size: 2mm × 3mm × 0.75mm
Pricing: 1,000-piece pricing starts at $2.25 each.

For more information, visit www.linear.com