Quad Output, Multiphase Step-Down Voltage Mode DC/DC Controller with Accurate Current Sharing

The LTC7851/LTC7851-1 are quad output multiphase synchronous step-down switching regulator controllers that employ a constant frequency voltage mode architecture. They maintain excellent current balance between channels when paralleled with their internal current sharing loop. Lossless DCR or a low value RSENSE is used for output current sensing. Multiple LTC7851/LTC7851-1 devices can be used for high phase count operation.

A very low offset, high bandwidth error amplifier, combined with remote output voltage sensing, provides excellent transient response and output regulation. The LTC7851/ LTC7851-1 operates with a VCC supply voltage from 3V to 5.5V and is designed for step-down conversion with VIN from 3V to 27V and produces an output voltage from 0.6V to VCC – 0.5V.

The LTC7851-1 is identical to the LTC7851 except it has a lower current sense amplifier gain, making it ideal for DrMOS devices with internal current sense.

Applications

* High Current Distributed Power Systems

* DSP, FPGA and ASIC Supplies

* Datacom, Telecom and Computing Systems

* Operates with Power Blocks, DrMOS or External Gate Drivers and MOSFETs

* Voltage Mode Control with Accurate Current Sharing

* ±0.75% 0.6V Voltage Reference

* Quad Differential Output Voltage Sense Amplifiers

* Multiphase Capability

* Phase-Lockable Fixed Frequency 250kHz to 2.25MHz

* Lossless Current Sensing Using Inductor DCR or Precision Current Sensing with Sense Resistor or DrMOS with Integrated Current Sensing

* VCC Range: 3V to 5.5V

* VOUT Range: 0.6V to VCC – 0.5V

* Power Good Output Voltage Monitor

* Output Voltage Tracking Capability with Soft-Start

* Available in 58-Lead 5mm × 9mm QFN Package