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ADP1851:  Wide Range Input, Synchronous, Step-Down DC-to-DC Controller

Product Details

Product Status:Recommended for New Designs

The ADP1851 is a wide range input, dc-to-dc, synchronous buck controller capable of running from commonly used 3.3 V to 12 V (up to 20 V) voltage inputs. The device nominally operates in current mode with valley current sensing providing the fastest step response for digital loads. It can also be configured as a voltage mode controller with low noise and crosstalk for sensitive loads.

The ADP1851 is ideal in system applications requiring multiple output voltages. The ADP1851 includes a synchronization feature to eliminate beat frequencies between switching devices. It also provides accurate tracking capability between supplies and includes precision enable and power-good functions for simple, robust sequencing.

The ADP1851 provides a high speed, high peak current gate driving capability to enable energy efficient power conversion. The device can be configured to operate in power saving mode by skipping pulses, reducing switching losses, and improving efficiency at light load and standby conditions.

The accurate current limit allows design within a narrower range of tolerances and can reduce overall converter size and cost. The ADP1851 can regulate down to 0.6 V output using a high accuracy reference with ±1% tolerance over the temperature range of −40°C to +125°C.

With its wide range input voltage, the ADP1851 provides the designer with maximum flexibility for use in a variety of system configurations; loop compensation, soft start, frequency setting, power saving mode, current limit, and current sense gain can all be programmed using external components. In addition, the external RAMP resistor allows the selection of optimal slope and VIN feedforward in both current and voltage modes for excellent line rejection. The linear regulator and the bootstrap diode for the high-side driver are internal.

Protection features include undervoltage lockout, overvoltage, overcurrent/short circuit, and overtemperature.


  • Intermediate bus and POL systems requiring sequencing and tracking, including
  • Telecom base station and networking
  • Industrial and instrumentation
  • Medical and healthcare


  • Input voltage range:
    2.75 V to 20 V
  • Output voltage range:
    0.6 V to 90% VIN
  • Maximum output current of more than 25 A
  • Current mode architecture
  • Configurable to voltage mode
  • ±1% output voltage accuracy over temperature
  • Voltage tracking
  • Programmable frequency: 200 kHz to 1.5 MHz
  • Synchronization input
  • Power saving mode at light load
  • Precision enable input
  • See data sheet for additional features

Typical Circuit Diagram for ADP1851


Title Content Type File Type
ADP1851: Wide Range Input, Synchronous, Step-Down DC-to-DC Controller Data Sheet (Rev 0, 08/2012) (pdf, 1501 kB) Data Sheets PDF
Introduction to ADIsimPower
ADIsimPower is a smart selector and a collection of downloadable tools that produce complete and optimized power designs. Schematic, bill of materials, and performance data are customized to your specific needs in minutes.
Videos HTML
UG-443: Evaluation Board for the ADP1851 Step-Down DC-to-DC Controller  (pdf, 1163 kB) User Guides PDF
Glossary of EE Terms Glossary HTML

Design Tools,Models,Drivers & Software

Title Content Type File Type
ADIsimPE Linear and Mixed-Signal Circuit Simulator
ADIsimPE is powered by SIMetrix/SIMPLIS and is a circuit simulation suite optimized for the design and development of analog and mixed signal circuits.
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ADP1851-53 Buck Designer Tool  (zip, 0)
Microsoft Excel download tool from ADIsimPower to generate a power supply design complete with a schematic, bill of materials, and performance specifications.
ADIsim Design/Simulation Tools ZIP
Download files for ADIsimPower™ Voltage Regulator Design Tool
The individual Excel-based voltage regulator design tools used in ADIsimPower™.
ADIsim Design/Simulation Tools HTML
ADIsimPower™ Voltage Regulator Design Tool
This expert design tool produces custom DC-DC converter designs in about a minute. The user enters 5 inputs and chooses to optimize for efficiency, PCB space, cost, or part count. Output is a complete schematic, BOM, efficiency plot, and performance summary. A PDF summary and a blank PCB is offered for each design to facilitate fast prototyping to verify the design.
ADIsim Design/Simulation Tools HTML
Launch of ADIsimPower Voltage Regulator Selection Vin (min) V Vout V   Find Solutions
Vin (max) V Iout A

Evaluation Kits & Symbols & Footprints

Evaluation Boards & KitsView the Evaluation Boards and Kits page for documentation and purchasing

Symbols and Footprints— Analog Devices offers Symbols & Footprints which are compatible with a large set of today’s CAD systems for broader and easier support.

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Price, packaging, availability

Price Table Help

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 Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.

ADP1851 Evaluation Board
Model Description Price RoHS View PCN/ PDN Check Inventory/
ADP1851-EVALZ Status: Production Evaluation Board $60.00 Yes -

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