LTC3868

PRODUCTION

Low I_Q, Dual 2-Phase Synchronous Step-Down Controller

Part Models: 4
1ku List Price: Starting From $3.26

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Part Details

Low Operating I_Q: 170μA (One Channel On)
Wide Output Voltage Range: 0.8V ≤ V_OUT ≤ 14V
Wide V_IN Range: 4V to 24V
R_SENSE or DCR Current Sensing
Out-of-Phase Controllers Reduce Required Input Capacitance and Power Supply Induced Noise
OPTI-LOOP^® Compensation Minimizes C_OUT
Phase-Lockable Frequency (75kHz to 850kHz)
Programmable Fixed Frequency (50kHz to 900kHz)
Selectable Continuous, Pulse-Skipping or Burst Mode^® Operation at Light Loads
Very Low Dropout Operation: 99% Duty Cycle
Adjustable Output Voltage Soft-Start
Power Good Output Voltage Monitor
Output Overvoltage Protection
Output Latchoff Protection During Short Circuit
Low Shutdown I_Q: 8μA
Internal LDO Powers Gate Drive from V_IN or EXTV_CC
No Current Foldback During Start-Up
Small 5mm × 5mm QFN Package

The LTC3868 is a high performance dual step-down switching regulator controller that drives all N-channel synchronous power MOSFET stages. A constant frequency current mode architecture allows a phase-lockable frequency of up to 850kHz. Power loss and noise due to the input capacitor ESR are minimized by operating the two controller outputs out of phase.

The 170μA no-load quiescent current extends operating life in battery-powered systems. OPTI-LOOP compensation allows the transient response to be optimized over a wide range of output capacitance and ESR values. The LTC3868 features a precision 0.8V reference and a power good output indicator. A wide 4V to 24V input supply range encompasses a wide range of intermediate bus voltages and battery chemistries.

Independent soft-start pins for each controller ramp the output voltages during start-up. Current foldback limits MOSFET heat dissipation during short-circuit conditions. The output short-circuit latchoff feature further protects the circuit in short-circuit conditions.

For a leaded 28-lead SSOP package with a fixed current limit and one PGOOD output, without phase modulation or a clock output, see the LTC3868-1 data sheet.


	LTC3868	LTC3868-1
Features	Adjustable Current Limit, Clock Out Pin, Phase Modulation, Two PGOOD	Fixed Current Limit, One PGOOD
Package	QFN-32	SSOP-28

Applications

Notebook and Palmtop Computers
Portable Instruments
Battery Operated Digital Devices
Distributed DC Power Systems

Part Models: 4
1ku List Price: Starting From $3.26

Documentation

Data Sheet 1

LTC3868: Low I_Q, Dual 2-Phase Synchronous Step-Down Controller Data Sheet 10/07/2014

Reliability Data 1

R526 Reliability Data 03/26/2018

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
LTC3868EUH#PBF	32-Lead QFN (5mm x 5mm x 0.75mm w/ EP)	Material Declaration Reliablity Data	Ultra Librarian SamacSys
LTC3868EUH#TRPBF	32-Lead QFN (5mm x 5mm x 0.75mm w/ EP)	Material Declaration Reliablity Data	Ultra Librarian SamacSys
LTC3868IUH#PBF	32-Lead QFN (5mm x 5mm x 0.75mm w/ EP)	Material Declaration Reliablity Data	Ultra Librarian SamacSys
LTC3868IUH#TRPBF	32-Lead QFN (5mm x 5mm x 0.75mm w/ EP)	Material Declaration Reliablity Data	Ultra Librarian SamacSys

Part Models	Product Lifecycle	PCN

Feb 14, 2025 - 25_0017 Bond Wire Change from Gold to Copper
		PCN25_0017_Form Material_Report Qualification Results Summary
LTC3868EUH#PBF	PRODUCTION
LTC3868EUH#TRPBF	PRODUCTION
LTC3868IUH#PBF	PRODUCTION
LTC3868IUH#TRPBF	PRODUCTION
Jan 20, 2022 - 21_0269 Addition of Alternate Assembly Site ASE Taiwan for Select LFCSP Products
		PCN21_0269_Form Material_Report Detailed Change Description Qualification Results Summary
LTC3868EUH#PBF	PRODUCTION
LTC3868EUH#TRPBF	PRODUCTION
LTC3868IUH#PBF	PRODUCTION
LTC3868IUH#TRPBF	PRODUCTION
Jul 31, 2020 - 20_0245 Notification of Wafer Fab Location Change for 0.6µm BICMOS Process Devices from ADI Milpitas (Hillview) to Vanguard Int. (Taiwan)
		PCN20_0245_Form Material_Report Delta Qualification Matrix Other Qualification Results Summary
LTC3868EUH#PBF	PRODUCTION
LTC3868EUH#TRPBF	PRODUCTION
LTC3868IUH#PBF	PRODUCTION
LTC3868IUH#TRPBF	PRODUCTION

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

Software Resources

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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
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LTC2960	RECOMMENDED FOR NEW DESIGNS	36V Nano-Current Two-Input Voltage Monitor
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LTC2955	RECOMMENDED FOR NEW DESIGNS	Pushbutton On/Off Controller with Automatic Turn-On
Surge Stopper, Overvoltage, and Overcurrent Protection 1
LTC4365	RECOMMENDED FOR NEW DESIGNS	Overvoltage, Undervoltage and Reverse Supply Protection Controller

Tools & Simulations

LTspice 1

LTC3868 - Step-Down (Buck) Regulators

Models for the following parts are available in LTspice:

LTC3868
LTC3868-1

LTpowerCAD 1

LTC3868 Project - Ref. Design 12V/10A 5V/10A, Rsense, 300kHz

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.

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