Power Management Switching Regulator Step-Down (Buck) Regulators Multiple Output Buck
Power Management Switching Regulator Step-Down (Buck) Regulators External Power Switch Buck Controllers

LTC2960 - 36V Nano-Current Two-Input Voltage Monitor

LTC3880 - Dual Output PolyPhase Step-Down DC/DC Controller with Digital Power System Management

LTC3858-2 - Low IQ, Dual 2-Phase Synchronous Step-Down Controller

Features

  • Low Operating IQ: 170μA (One Channel On)
  • Wide Output Voltage Range: 0.8V ≤ VOUT ≤ 24V
  • Wide VIN Range: 4V to 38V
  • RSENSE or DCR Current Sensing
  • Out-of-Phase Controllers Reduce Required Input Capacitance and Power Supply Induced Noise
  • OPTI-LOOP® Compensation Minimizes COUT
  • 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 or Tracking
  • Power Good Output Voltage Monitor
  • Low Shutdown IQ: 8μA
  • Internal LDO Powers Gate Drive from VIN or EXTVCC
  • No Current Foldback During Start-Up
  • 5mm × 5mm QFN Package

Typical Application

LTC3858-2 Typical Application
LTC3858-2 Typical Application

Description

The LTC3858-2 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 LTC3858-2 differs from the LTC3858 by having the overvoltage protection crowbar and short-circuit latchoff disabled. 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. Current foldback limits MOSFET heat dissipation during short-circuit conditions.

 LTC3858LTC3858-1LTC3858-2
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

Packaging

CAD Symbols and Footprints: The downloadable Zip file below contains the schematic symbol and PCB footprints.

For complete and up to date package information and drawings, please refer to our packaging page

Part Number Package Code Temp Package
Drawing		 RoHS
LTC3858EUH-2#PBF 5x5 QFN-32 UH E 05-08-1693 Yes
LTC3858EUH-2#TRPBF 5x5 QFN-32 UH E 05-08-1693 Yes
LTC3858IUH-2#PBF 5x5 QFN-32 UH I 05-08-1693 Yes
LTC3858IUH-2#TRPBF 5x5 QFN-32 UH I 05-08-1693 Yes


LTC3858-2 Package Drawing

Order Info

  • Part numbers ending in PBF are lead free. Solder plated terminal finish (SnPb) versions are non-standard and special terms and conditions and pricing applies if available. Please contact LTC marketing for information.
  • Part numbers containing TR or TRM are shipped in tape and reel or 500 unit mini tape and reel, respectively
  • Please refer to our general ordering information or the product datasheet for more details

Package Variations and Pricing

Part Number Package Temp Price
(1-99)		 Price
(1k)*		 RoHS
LTC3858EUH-2#PBF 5x5 QFN-32 E $5.71 $4.00 Yes
LTC3858EUH-2#TRPBF 5x5 QFN-32 E $4.06 Yes
LTC3858IUH-2#PBF 5x5 QFN-32 I $6.06 $4.24 Yes
LTC3858IUH-2#TRPBF 5x5 QFN-32 I $4.30 Yes
Buy Now • Request Samples
* 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 Linear Technology sales office or authorized distributor.

Demo Boards

Linear Technology offers many demo boards free of charge to qualified customers. Contact your local sales office or distributor to inquire about a demo board. Certain demo boards are also available for sale via credit card on this website. Demo boards are for evaluation purposes only. It remains the customer’s responsibility to verify proper and reliable operation in the actual end application.

Click here to view our complete list of demo boards

Applications

  • Automotive Systems
  • Battery Operated Digital Devices
  • Distributed DC Power Systems

People Who Viewed This Product Also Viewed

Product Notifications

Please login to your MyLinear account for notifications of datasheet updates, new document releases and LTspice model announcements for your favorite products. If you do not have a MyLinear account you may Sign Up Now.

Forgot your password? Click here.
Need help? Email mylinear@linear.com with questions and comments.

Design Tools

LTspice

LTspice® software is a powerful, fast and free simulation tool, schematic capture and waveform viewer with enhancements and models for improving the simulation of switching regulators. Click here to download LTspice

Models for the following parts are available in LTspice:
LTC3858
LTC3858-1
LTC3858-2

LTpowerCAD

The LTpowerCAD design tool is a complete power supply design tool program that can significantly ease the tasks of power supply design. It guides users to a solution, selects power stage components, provides detailed power efficiency, shows quick loop bode plot stability and load transient analysis, and can export a final design to LTspice for simulation. Click here to download LTpowerCAD

Design tools for the following parts are available in LTpowerCAD:
LTC3858
LTC3858 Parallel
LTC3858-1
LTC3858-1 Parallel
LTC3858-2
LTC3858-2 Parallel

Technical Support