1. Products
  2. Power Management
  3. Switching Regulators
  4. Step-Down (Buck) Regulators
  5. External Power Switch Buck Controllers
  6. ADP1851


Features and Benefits

  • 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
  • Power good with internal pull-up resistor
  • Adjustable soft start
  • Programmable current sense gain
  • Integrated bootstrap diode
  • Starts into a precharged load
  • Externally adjustable slope compensation
  • Suitable for any output capacitor
  • Overvoltage and overcurrent-limit protection
  • Thermal overload protection
  • Input undervoltage lockout (UVLO)
  • Available in 16-lead, 4 mm × 4 mm LFCSP
  • Supported by ADIsimPower design tool

Product Details

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

Product Lifecycle icon-recommended Recommended for New Designs

This product has been released to the market. The data sheet contains all final specifications and operating conditions. For new designs, ADI recommends utilization of these products.

Evaluation Kits (1)

Tools & Simulations


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.


Models for the following parts are available in LTspice:


Design Tool

ADP1851-53 Buck Designer Tool

Microsoft Excel download tool from ADIsimPower to generate a power supply design complete with a schematic, bill of materials, and performance specifications.

Design Resources

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 Number Material Declaration Reliability Data Pin/Package Drawing CAD Symbols, Footprints & 3D Models
ADP1851ACPZ-R7 Material Declaration Reliability Data 16-Lead LFCSP (4mm x 4mm)
Wafer Fabrication Data

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Sample & Buy

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Evaluation Boards

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Pricing displayed is based on 1-piece. The USA list pricing shown is for budgetary use only, shown in United States dollars (FOB USA per unit), and is subject to change. International prices may vary due to local duties, taxes, fees and exchange rates.