LTC3838

RECOMMENDED FOR NEW DESIGNS

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

Part Models: 8
1ku List Price: Starting From $3.47

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Part Details

Wide V_IN Range: 4.5V to 38V, V_OUT: 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 V_OUT Overshoot
Frequency Programmable from 200kHz to 2MHz, Synchronizable to External Clock
t_ON(MIN) = 30ns, t_OFF(MIN) = 90ns
R_SENSE 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 and TSSOP packages

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 V_IN, V_OUT 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 t_ON and t_OFF 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

Part Models: 8
1ku List Price: Starting From $3.47

Documentation

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. View our quality and reliability program and certifications for more information.

Part Model	Pin/Package Drawing	Documentation	CAD Symbols, Footprints, and 3D Models
LTC3838EFE#PBF	38-Lead TSSOP w/ EP	Material Declaration Reliablity Data	Ultra Librarian SamacSys
LTC3838EFE#TRPBF	38-Lead TSSOP w/ EP	Material Declaration Reliablity Data	Ultra Librarian SamacSys
LTC3838EUHF#PBF	38-Lead QFN (5mm x 7mm w/ EP)	Material Declaration Reliablity Data	Ultra Librarian SamacSys
LTC3838EUHF#TRPBF	38-Lead QFN (5mm x 7mm w/ EP)	Material Declaration Reliablity Data	Ultra Librarian SamacSys
LTC3838IFE#PBF	38-Lead TSSOP w/ EP	Material Declaration Reliablity Data	Ultra Librarian SamacSys
LTC3838IFE#TRPBF	38-Lead TSSOP w/ EP	Material Declaration Reliablity Data	Ultra Librarian SamacSys
LTC3838IUHF#PBF	38-Lead QFN (5mm x 7mm w/ EP)	Material Declaration Reliablity Data	Ultra Librarian SamacSys
LTC3838IUHF#TRPBF	38-Lead QFN (5mm x 7mm w/ EP)	Material Declaration Reliablity Data	Ultra Librarian SamacSys

Part Models	Product Lifecycle	PCN

Apr 6, 2022 - 22_0068 Laser Top Mark for ETSSOP and TSSOP Packages Assembled in ADPG [PNG] and UTL
		PCN22_0068_Form Material_Report Delta Qualification Matrix
LTC3838EFE#PBF	PRODUCTION
LTC3838EFE#TRPBF	PRODUCTION
LTC3838IFE#PBF	PRODUCTION
LTC3838IFE#TRPBF	PRODUCTION

This is the most up-to-date revision of the Data Sheet.

Hardware Ecosystem

Parts	Product Life Cycle	Description
Digital Power System Managers 1
LTC2974	RECOMMENDED FOR NEW DESIGNS	4-Channel PMBus Power System Manager Featuring Accurate Output Current Measurement
Dual-Supply Monitors 1
LTC2960	RECOMMENDED FOR NEW DESIGNS	36V Nano-Current Two-Input Voltage Monitor
Multiple Output Buck Regulators 1
LTC3880	RECOMMENDED FOR NEW DESIGNS	Dual Output PolyPhase Step-Down DC/DC Controller with Digital Power System Management
Surge Stopper, Overvoltage, and Overcurrent Protection 1
LT4363	RECOMMENDED FOR NEW DESIGNS	High Voltage Surge Stopper with Current Limit

Tools & Simulations

LTspice 3

Models for the following parts are available in LTspice:

LTC3838
LTC3838-1
LTC3838-2

LTpowerCAD 4

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.

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.

Evaluation Kits

LTC3838EFE Demo Board (RSENSE) | 4.5V ≤ VIN ≤ 26V; VOUT1 = 1.2V @ 15A, VOUT2 = 1.5V @ 15A

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Product Details

Demonstration circuit 1626A is a dual output 1.5V/15A and 1.2V/15A synchronous buck converter operating with a switching frequency of 300kHz over an input voltage range of 4.5V to 26V. The demo board comes in two versions. The -A version uses inductor DCR current sensing with an iron powder inductor for high efficiency. The -B version uses a 2.5mΩ sense resistor for accurate current sensing with a low DCR ferrite inductor.

Resources

DC1626A - Schematic
89.00K

DC1626A - Demo Manual
276.00K

DC1626A - Design File
1.00M

LTC3838EFE Demo Board (DCR Sense) | 4.5V ≤ VIN ≤ 26V; VOUT1 = 1.2V @ 15A, VOUT2 = 1.5V @ 15A

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Product Details

Resources

DC1626A - Schematic
89.00K

DC1626A - Demo Manual
276.00K

DC1626A - Design File
1.00M

LTC3838EUHF Demo Board (RSENSE) | VIN = 4.5V to 14V, VOUT1 = 1.2V @ 20A, VOUT2 = 1.5V @ 20A

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Product Details

Demonstration circuit 1801A is a dual output 1.5V/20A and 1.2V/20A synchronous buck converter operating with a switching frequency of 300kHz over an input voltage range of 4.5V to 14V. The demo board comes in two versions. The A version uses inductor DCR current sensing for high efficiency. The B version uses 2mΩ sense resistor for accurate current sensing with a low DCR ferrite inductor. The fixed on-time valley current mode topology of the LTC3838 allows for a fast load step response.