Dual, Fast, Accurate Step-Down DC/DC Controller with Dual Differential Output Sensing

The LTC3838-1 is a dual-channel, PolyPhase® synchronous step-down DC/DC switching regulator controller. Two independent channels drive all N-channel power MOSFETs. The controlled on-time, valley current mode control architecture allows for not only fast response to transients without clock delay, but also constant frequency switching at steady load condition. Its proprietary load-release transient detection feature (DTR) significantly reduces overshoot at low output voltages.

A precision internal reference enables accurate differential output regulation. The dual channels can either provide two independent output voltages, or be combined into multiphase single-output configuration.

The switching frequency can be programmed from 200kHz to 2MHz with an external resistor and can be synchronized to an external clock. Very low tON and tOFF times allow for near 0% and near 100% duty cycles, respectively. Voltage tracking soft start-up and multiple safety features are provided.

See below for a comparison of LTC3838, LTC3838-1 and LTC3838-2.

Part Number

Description

LTC3838

±0.67% Differential Output Voltage Accuracy Over Temperature on Channel 1, ±1% Output Regulation on Channel 2, Separate Per Channel 30mV to 100mV Current Sense Range Controls

LTC3838-1

±0.67% Differential Output Voltage Accuracy Over Temperature on Both Channel 1 and Channel 2, Single Pin 30mV/60mV Current Sense Range Controls

LTC3838-2

±0.67% Differential Output Voltage Accuracy With Internal Reference on Channel 1, ±4mV Differential with External Reference Voltage on Channel 2, Fixed 30mV Current Sense Range

Applications

* Distributed Power Systems; Power Supply for ASIC

* Computing, Data Storage, Communication Systems

* Low Voltage, High Current, and/or High Step-Down Ratio Converters That Demand Tight Load Transient Regulation

* Wide VIN Range: 4.5V to 38V, VOUT: 0.6V to 5.5V

* Two Independent Channels: Dual/Single Output

* Output Voltage Regulation Accuracy: ±0.67% (VOUT1) and ±0.75% (VOUT2) Over Temperature

* Differential Remote Output Sensing: Up to ±500mV (VOUT1) and ±200mV (VOUT2) Ground Deviations

* Controlled On-Time, Valley Current Mode Control

* Fast Load Transient Response Without Clock Delay