LTC3857
Info: : PRODUCTION
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LTC3857

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

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Info: : PRODUCTION tooltip
Info: : PRODUCTION tooltip
Part Details
Part Models 4
1ku List Price Starting From $4.78
Features
  • Low Operating IQ: 50μA (One Channel On)
  • Wide Output Voltage Range: 0.8V ≤ VOUT ≤ 24V
  • Wide VIN Range: 4V to 38V (40V Abs Max)
  • 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 Low Ripple Burst Mode® Operation at Light Loads
  • Selectable Current Limit
  • Very Low Dropout Operation: 99% Duty Cycle
  • Adjustable Output Voltage Soft-Start or Tracking
  • Power Good Output Voltage Monitors
  • Output Overvoltage Protection
  • Low Shutdown IQ : <8μA
  • Internal LDO Powers Gate Drive from VIN or EXTVCC
  • No Current Foldback During Start-up
  • 5mm × 5mm QFN Package
Additional Details
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The LTC3857 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 ESR of the input capacitor ESR are minimized by operating the two controller output stages out of phase.

The 50μA no-load quiescent current extends operating run time in battery-powered systems. The LTC3857 features a precision 0.8V reference and power good output indicators. A wide 4V to 38V input supply range encompasses a wide range of intermediate bus voltages and battery chemistries.

Independent TRACK/SS pins for each controller ramp the output voltages during start-up. Current foldback limits MOSFET heat dissipation during short-circuit conditions. The PLLIN/MODE pin selects among Burst Mode operation, pulse-skipping mode, or continuous inductor current mode at light loads.

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 LTC3857-1 data sheet.


  LTC3857 LTC3857-1
Features   Adjustable Current Limit, Clock Output, Phase Modulation, 2 PGOOD Outputs Fixed Current Limit, One PGOOD Output
Package QFN-32 SSOP-28

Applications

  • Automotive Always-On Systems
  • Battery Operated Digital Devices
  • Distributed DC Power Systems

Part Models 4
1ku List Price Starting From $4.78

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Documentation

Documentation

Part Model Pin/Package Drawing Documentation CAD Symbols, Footprints, and 3D Models
LTC3857EUH#PBF
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LTC3857EUH#TRPBF
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LTC3857IUH#PBF
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LTC3857IUH#TRPBF
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Product Lifecycle

PCN

Jun 1, 2022

- 22_0120

LTC3857 New Wire Bonding

LTC3857EUH#PBF

PRODUCTION

LTC3857EUH#TRPBF

PRODUCTION

LTC3857IUH#PBF

PRODUCTION

LTC3857IUH#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)

LTC3857EUH#PBF

PRODUCTION

LTC3857EUH#TRPBF

PRODUCTION

LTC3857IUH#PBF

PRODUCTION

LTC3857IUH#TRPBF

PRODUCTION

Filter by Model

reset

Reset Filters

Part Models

Product Lifecycle

PCN

Jun 1, 2022

- 22_0120

arrow down

LTC3857 New Wire Bonding

LTC3857EUH#PBF

PRODUCTION

LTC3857EUH#TRPBF

PRODUCTION

LTC3857IUH#PBF

PRODUCTION

LTC3857IUH#TRPBF

PRODUCTION

Jul 31, 2020

- 20_0245

arrow down

Notification of Wafer Fab Location Change for 0.6µm BICMOS Process Devices from ADI Milpitas (Hillview) to Vanguard Int. (Taiwan)

LTC3857EUH#PBF

PRODUCTION

LTC3857EUH#TRPBF

PRODUCTION

LTC3857IUH#PBF

PRODUCTION

LTC3857IUH#TRPBF

PRODUCTION

Software & Part Ecosystem

Software & Part Ecosystem

Evaluation Kit

Evaluation Kits 1

reference details image

DC1381A-A

LTC3857IUH Demo Board | 4.5V ≤ VIN ≤ 36V, VOUT1 = 3.3V @ 5A, VOUT2 = 8.5V @ 3A

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DC1381A-A

LTC3857IUH Demo Board | 4.5V ≤ VIN ≤ 36V, VOUT1 = 3.3V @ 5A, VOUT2 = 8.5V @ 3A

LTC3857IUH Demo Board | 4.5V ≤ VIN ≤ 36V, VOUT1 = 3.3V @ 5A, VOUT2 = 8.5V @ 3A

Product Detail

Demonstration circuit 1381A is a Low Quiescent Current, Dual Output Synchronous Buck Converter featuring the LTC3857EUH/LTC3858EUH. The DC1381A provides 3.3V/5A and 8.5V/3A from a wide input voltage range of 4.5V to 36V, making it suitable for automotive or other battery fed application where low quiescent current is important.


Two versions of the board are available. DC-1381A-A is for the LTC3857EUH, while the DC1381A-B is for the LTC3858EUH. The LTC3857EUH offers lower quiescent current and smaller burst mode ripple, while the LTC3858EUH offers latch-off protection and increased burst mode efficiency.

Tools & Simulations

Tools & Simulations 2

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.

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