Features and Benefits
- 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
- 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
- Output Voltage Tracking and Adjustable Soft Start-Up
- Thermally Enhanced 38-Pin (5mm × 7mm) QFN Package
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.
|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|
- 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
Product Lifecycle Production
At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.
Evaluation Kits (1)
Demonstration circuit DC1997A is a dual output synchronous buck converters featuring the LTC3838EUHF-1 (DC1997A-A) or the LTC3838EUHF-2 (DC1997A-B). Both assemblies provide two outputs of 1.5V/20A and 1.2V/20A over an input voltage range of 4.5V to 14V at a switching frequency of 300kHz. The LTC3838-1 and LTC3838-2 provide dual differential VOUT sensing while the dual LTC3838 (plain) has differential VOUT sensing on one channel. The "-2" version has an external reference input for channel 2.
Tools & Simulations
LTspice® is a powerful, fast and free simulation software, schematic capture and waveform viewer with enhancements and models for improving the simulation of analog circuits.
To launch ready-to-run LTspice demonstration circuits for this part:
Step 1: Download and install LTspice on your computer.
Step 2: Click on the link in the section below to download a demonstration circuit.
Step 3: If LTspice does not automatically open after clicking the link below, you can instead run the simulation by right clicking on the link and selecting “Save Target As.” After saving the file to your computer, start LTspice and open the demonstration circuit by selecting ‘Open’ from the ‘File’ menu.
Models for the following parts are available in LTspice:
LTpowerCAD® is a power supply design program which selects power stage components, provides detailed power efficiency, shows quick loop Bode plot stability and load transient analysis, and can export to LTspice for simulation.
Design tools for the following parts are available in LTpowerCAD:
ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal.
Sample & Buy
The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.