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

The LTC3838 is a dual, 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 fast transient response and constant frequency switching in steady-state operation, independent of VIN, VOUT and load current. Its load-release transient detection feature significantly reduces overshoot at low output voltages.

Differential output voltage sensing, along with a precision internal reference, offers an accurate ±0.67% output regulation on Channel 1, even if the remote output ground deviates from local ground by ±500mV. The second channel can either provide an independent ±1% output, or together with the first channel of this controller, serve as one of the PolyPhase channels for a single-output voltage.

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

* Point-of-Load Converters

* Computing Systems

* Data Communication Systems

* Wide VIN Range: 4.5V to 38V, VOUT: 0.6V to 5.5V* ±0.67% Output Voltage Accuracy Over Temperature, Differential Output Voltage Sensing, Allowing Up to ±500mV Line Loss at Remote Ground on Channel 1* ±1% Output on the Independent 2nd Channel* Controlled On-Time, Valley Current Mode Control* Fast Load Transient Response* Detect Transient (DTR) Reduces VOUT Overshoot