3-V to 20-V, voltage mode synchronous buck controller with DCR current sensing


Product details


Vin (Min) (V) 3 Vin (Max) (V) 20 Vout (Min) (V) 0.6 Vout (Max) (V) 18.6 Iout (Max) (A) 30 Iq (Typ) (uA) 4500 Switching frequency (Min) (kHz) 200 Switching frequency (Max) (kHz) 1200 Features Enable, Frequency Synchronization, Power Good, Pre-Bias Start-Up, Synchronous Rectification, Tracking 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

HTSSOP (PWP) 16 32 mm² 5 x 6.4 WQFN (RUM) 16 16 mm² 4 x 4 open-in-new Find other Buck controllers (external switch)


  • Wide Input-Voltage Range of 3 V to 20 V
  • Inductor DCR or Shunt Resistor Based Overcurrent Protection
  • 0.6-V Reference With ±1% FB Accuracy Across Full –40°C to 125°C Junction Temperature Range
  • Switching Frequency from 200 kHz to 1.2 MHz
  • Output Voltage as High as 95% of Input Voltage
  • Integrated High-Current MOSFET Drivers
  • Internal VDD Bias Supply LDO Subregulator
  • External Clock Synchronization
  • Adjustable Soft Start With External Capacitor
  • Prebiased Start-up Capability
  • Power Supply Tracking
  • Voltage-Mode Control With Line Feedforward
  • Open-Drain Power-Good Indicator
  • Precision Enable With Hysteresis
  • 16-Pin HTSSOP and WQFN Packages
  • Create a Custom Design Using the LM27402 With the WEBENCH® Power Designer
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The LM27402 is a voltage-mode, synchronous, DC/DC step-down controller with lossless inductor DCR current sensing capability. Sensing the inductor current eliminates the need to add resistive powertrain elements, which increases overall efficiency and facilitates accurate, continuous current sensing. A 0.6-V ±1% voltage reference enables high accuracy and low voltage capability at the output. An input operating voltage range of 3 V to 20 V makes the LM27402 suitable for a large variety of input rails.

The LM27402 voltage-mode control loop incorporates input voltage feed forward to maintain stability throughout the entire input-voltage range. The switching frequency is adjustable from 200 kHz to
1.2 MHz. Dual, high-current, integrated MOSFET drivers support large QG, low RDS(on) power MOSFETs. A power-good indicator provides power-rail-sequencing capability and output fault detection. An adjustable external soft start limits inrush current and provides monotonic output control during start-up. Other features include external tracking of other power supplies, integrated LDO bias supply, and synchronization capability.

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Technical documentation

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Type Title Date
* Data sheet LM27402 High-Performance Synchronous Buck Controller With DCR Current Sensing datasheet (Rev. K) Feb. 23, 2018
Selection guide Power Management Guide 2018 (Rev. R) Jun. 25, 2018
Application note Common mistakes made in controller designs for power converters Mar. 26, 2018
Application note Using DC/DC Controllers to Improve Bitcoin Miner Designs Mar. 15, 2018
Application note Reduce buck-converter EMI and voltage stress by minimizing inductive parasitics Jul. 21, 2016
Technical article High Density PCB Layout of DC/DC Converters, Part 2 Sep. 16, 2015
Technical article High Density PCB Layout of DC/DC Converters, Part 1 Sep. 12, 2015
User guide AN-1992 LM27402 Evaluation Board (Rev. B) May 06, 2013
Application note AN-2060 LM27402 Current Limit Application Circuits (Rev. A) May 06, 2013
Application note Current Limit Foldback Improves Short Circuit Protection in LM274X Family (Rev. B) Apr. 23, 2013

Design & development

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Hardware development

LM27402 Evaluation Board
document-generic User guide

The LM27402 evaluation board represents a 20A typical application circuit. The application circuit is optimized for an input voltage of 12V. However, input voltage feed-forward technology allows the evaluation board to operate up to 20V while maintaining a stable output voltage of 1.5V at 20A (...)

Design tools & simulation

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SNVM470.TSC (1870 KB) - TINA-TI Reference Design
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Reference designs

参考设计 Download
LM27402 Step-Down Regulator Delivering 1.2V at 3A Reference Design
PMP7882 — PMP7882 is a single-phase switching regulator accepting an input voltage range of 10.8Vin to 13.2Vin and providing an output voltage of 1.2Vout capable of supplying 12A of current. This design uses the LM27402 synchronous buck controller with lossless inductor DCR current sensing capability, which (...)

CAD/CAE symbols

Package Pins Download
HTSSOP (PWP) 16 View options
WQFN (RUM) 16 View options

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