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LTC3838-2 - Dual, Fast, Accurate Step-Down DC/DC Controller with External Reference Voltage and Dual Differential Output Sensing

The LTC®3838-2 is a dual-channel, PolyPhase® synchronous step-down DC/DC switching regulator controller. Two independent channels drive all N-channel power MOSFETs. The two channels can also be combined into a multiphase single output configuration with external reference.

The controlled on-time, valley current mode control architecture allows for not only fast response to transients without a clock delay, but also constant frequency switching at a steady-load condition. Its proprietary load-release transient detection feature (DTR) significantly reduces overshoot at low output voltages.

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 Table 1 for a comparison of LTC3838, LTC3838-1 and LTC3838-2.

Features Wide VIN Range: 4.5V to 38V VOUT1: 0.6V to 5.5V, ±0.67% Output Regulation Accuracy, with Internal 0.6V VREFERENCE VOUT2: 0.4V to 5.5V, ±4mV Regulation Accuracy, with Differential External VREFERENCE Sensing Differential Remote Output Sensing; Up to ±500mV (VOUT1) and ±200mV (VOUT2) Ground Deviations Fast Load Transient Response Without Clock Delay Detect Transient Release (DTR) Reduces VOUT Overshoot Frequency Programmable from 200kHz to 2MHz, Synchronizable to External Clock tON(MIN) = 30ns, tOFF(MIN) = 90ns RSENSE or Inductor DCR Current Sensing Overvoltage Protection and Current Limit Foldback Power Good Output Voltage Monitor Thermally Enhanced 38-Pin (5mm × 7mm) QFN Package Typical Application

Applications Power for ASICs with Dynamic Voltage Scaling Low Voltage, High Current, High Step-Down Ratio Converters That Demand Tight Transient Regulation Packaging

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