LTC3858-1

PRODUCTION

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

Part Models: 8
1ku List Price: Starting From $4.63

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Part Details

Low Operating I_Q: 170μA (One Channel On)
Wide Output Voltage Range: 0.8V ≤ V_OUT ≤ 24V
Wide V_IN Range: 4V to 38V
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-850kHz)
Programmable Fixed Frequency (50kHz-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 Latch-Off 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
Tiny 4mm × 5mm QFN and Narrow SSOP Packages

The LTC3858-1 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 LTC3858-1 features a precision 0.8V reference and a power good output indicator. A wide 4V to 38V 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. The output latch-off feature protects the circuit in short-circuit conditions.

For a leadless 32-pin QFN package with the additional features of adjustable current limit, clock out, phase modulation and two PGOOD outputs, see the LTC3858 data sheet.


	LTC3858	LTC3858-1	LTC3858-2
Features	Adjustable Current Limit, Clock Output, Phase Modulation, 2 PGOOD Outputs	Fixed Current Limit, One PGOOD Output	Overvoltage protection crowbar and short-circuit latchoff disabled
Package	QFN-32	SSOP-28	QFN-32

Applications

Automotive Systems
Battery Operated Digital Devices
Distributed DC Power Systems

Part Models: 8
1ku List Price: Starting From $4.63

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
LTC3858EGN-1#PBF	28-Lead SSOP (Narrow 0.15 Inch)	Material Declaration Reliablity Data	Ultra Librarian SamacSys
LTC3858EGN-1#TRPBF	28-Lead SSOP (Narrow 0.15 Inch)	Material Declaration Reliablity Data	Ultra Librarian SamacSys
LTC3858EUFD-1#PBF	28-Lead QFN (4mm x 5mm x 0.75mm w/ EP)	Material Declaration Reliablity Data	Ultra Librarian SamacSys
LTC3858EUFD-1#TRPBF	28-Lead QFN (4mm x 5mm x 0.75mm w/ EP)	Material Declaration Reliablity Data	Ultra Librarian SamacSys
LTC3858IGN-1#PBF	28-Lead SSOP (Narrow 0.15 Inch)	Material Declaration Reliablity Data	Ultra Librarian SamacSys
LTC3858IGN-1#TRPBF	28-Lead SSOP (Narrow 0.15 Inch)	Material Declaration Reliablity Data	Ultra Librarian SamacSys
LTC3858IUFD-1#PBF	28-Lead QFN (4mm x 5mm x 0.75mm w/ EP)	Material Declaration Reliablity Data	Ultra Librarian SamacSys
LTC3858IUFD-1#TRPBF	28-Lead QFN (4mm x 5mm x 0.75mm w/ EP)	Material Declaration Reliablity Data	Ultra Librarian SamacSys

Part Models	Product Lifecycle	PCN

Oct 3, 2024 - 24_0235 (QSOP/SSOP PKG) Migrating Bottom Trace Code Marking to Top Side Laser Marking
		PCN24_0235_Form Material_Report Other Delta Qualification Matrix
LTC3858EGN-1#PBF	PRODUCTION
LTC3858EGN-1#TRPBF	PRODUCTION
LTC3858IGN-1#PBF	PRODUCTION
LTC3858IGN-1#TRPBF	PRODUCTION
Aug 10, 2022 - 22_0177 Laser Top Mark Conversion for QSOP20_24_28 Assembled in ADPG [PNG] and UTL
		PCN22_0177_Form Material_Report Delta Qualification Matrix
LTC3858EGN-1#PBF	PRODUCTION
LTC3858EGN-1#TRPBF	PRODUCTION
LTC3858IGN-1#PBF	PRODUCTION
LTC3858IGN-1#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
LTC3858EGN-1#PBF	PRODUCTION
LTC3858EGN-1#TRPBF	PRODUCTION
LTC3858EUFD-1#PBF	PRODUCTION
LTC3858EUFD-1#TRPBF	PRODUCTION
LTC3858IGN-1#PBF	PRODUCTION
LTC3858IGN-1#TRPBF	PRODUCTION
LTC3858IUFD-1#PBF	PRODUCTION
LTC3858IUFD-1#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
LTC3858EUFD-1#PBF	PRODUCTION
LTC3858EUFD-1#TRPBF	PRODUCTION
LTC3858IUFD-1#PBF	PRODUCTION
LTC3858IUFD-1#TRPBF	PRODUCTION

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

Hardware Ecosystem

Parts	Product Life Cycle	Description
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
Pushbutton Controllers 1
LTC2955	RECOMMENDED FOR NEW DESIGNS	Pushbutton On/Off Controller with Automatic Turn-On
Surge Stopper, Overvoltage, and Overcurrent Protection 1
LT4363	RECOMMENDED FOR NEW DESIGNS	High Voltage Surge Stopper with Current Limit

Tools & Simulations

LTspice 1

LTC3858-1 Demo Circuit - Dual Synchronous Step Down (4.5-36V to 3.3V @ 5A & 8.5V @ 3A)

Models for the following parts are available in LTspice:

LTC3858
LTC3858-1
LTC3858-2

LTpowerCAD 1

LTC3858-1 Project - Low Iq, Dual 2-Phase Synchronous Step-Down Supply (9-36V to 3.3 @ 5A & 8.5 @ 3A)

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

LTC3858EGN-1 Demo Board | Dual Output, 2-Phase, 4.5V ≤ VIN ≤ 36V, VOUT1 = 3.3V @ 5A, VOUT2 = 8.5V @ 3A

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Product Details

Demonstration circuit 1352A is a low quiescent current, dual output 2-phase, synchronous buck converter demo board featuring the LTC3857EGN-1 or LTC3858EGN-1. It features a 4.5V to 36V input voltage range and provides 3.3V / 5A and 8.5V / 3A outputs. Two versions of the board are available. The DC-1352A-A is for the LTC3857EGN-1, which offers lower quiescent current and smaller burst mode ripple, while the DC1352A-B is for the LTC3858EGN-1 which offers latch-off protection and increased burst mode efficiency.

Resources

DC1352A - Schematic
89.00K

DC1352A - Demo Board
1.00M

DC1352A - Design Files
3.00M

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