Low-Voltage Synchronous Buck Controller with Precision Enable and No External Compensation


Product details


Vin (Min) (V) 2.8 Vin (Max) (V) 5.5 Vout (Min) (V) 0.8 Vout (Max) (V) 4.5 Iout (Max) (A) 6 Iq (Typ) (uA) 400 Switching frequency (Min) (kHz) 500 Switching frequency (Max) (kHz) 2000 Features Enable Operating temperature range (C) -40 to 125 Regulated outputs (#) 1 Number of Phases 1 Rating Catalog open-in-new Find other Buck controllers (external switch)

Package | Pins | Size

VSSOP (DGK) 8 15 mm² 3 x 4.9 WSON (NGG) 6 9 mm² 3 x 3 open-in-new Find other Buck controllers (external switch)


  • Input Voltage Range of 2.8 V to 5.5 V
  • 0.8-V Reference Voltage
  • Precision Enable
  • No Compensation Required
  • Constant Frequency Across Input Range
  • Low Quiescent Current of 400 µA
  • Internal Soft-Start
  • Short Circuit Protection
  • 6-Pin WSON Package and 8-Pin VSSOP Package
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The LM1771 device is an efficient synchronous buck switching controller with a precision enable requiring no external compensation. The constant ON-time control scheme provides a simple design free of compensation components, allowing minimal component count and board space. The precision enable pin allows flexibility in sequencing multiple rails and setting UVLO. The LM1771 also incorporates a unique input feedforward to maintain a constant frequency independent of the input voltage. The LM1771 is optimized for a low-voltage input range of 2.8 V to 5.5 V and can provide an adjustable output as low as 0.8 V. Driving an external high-side PFET and low-side NFET, it can provide efficiencies as high as 95%.

Three versions of the LM1771 are available depending on the switching frequency desired for the application. Nominal switching frequencies are in the range of 100 kHz to 1000 kHz.

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Technical documentation

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Type Title Date
* Datasheet LM1771 Low-Voltage Synchronous Buck Controller With Precision Enable and No External Compensation datasheet (Rev. D) Jan. 08, 2016
Technical articles How to implement voltage monitoring Jul. 22, 2015
User guide AN-1477 LM1771 Evaluation Board (Rev. B) Apr. 23, 2013
Application note Controlling Output Ripple & Achiev ESR Indep Constant On-Time Reg Designs (Rev. A) Apr. 23, 2013

Design & development

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Hardware development

document-generic User guide

LM1771 Low-Voltage Synchronous Buck Controller with Precision Enable and No External Compensation

  • Input voltage range of 2.8V to 5.5V
  • 0.8V reference voltage
  • Precision enable
  • No compensation required
  • Constant frequency across input range
  • Low quiescent current of 400 mA
  • Internal soft-start
  • Short circuit protection
  • Tiny LLP-6 package and MSOP-8 package


  • Simple to design, High-Efficiency Step-Down (...)

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  • Leverages Cadence PSpice Technology
  • Preinstalled library with a suite of digital models to enable worst-case timing analysis
  • Dynamic updates ensure you have access to most current device models
  • Optimized for simulation speed without loss of accuracy
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CAD/CAE symbols

Package Pins Download
VSSOP (DGK) 8 View options
WSON (NGG) 6 View options

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