LM5025A

ACTIVE

90V active clamp voltage mode PWM controller with P or N-channel clamp FET and 0.5V CS threshold

Product details

Vin (max) (V) 15 Operating temperature range (°C) -40 to 125 Control mode Feedforward Topology Active-clamp forward, Forward Rating Catalog Features Current limiting, High-voltage startup, Leading edge blanking, Soft start, Supports NFET clamp, Supports PFET clamp, Thermal shutdown Duty cycle (max) (%) 80
Vin (max) (V) 15 Operating temperature range (°C) -40 to 125 Control mode Feedforward Topology Active-clamp forward, Forward Rating Catalog Features Current limiting, High-voltage startup, Leading edge blanking, Soft start, Supports NFET clamp, Supports PFET clamp, Thermal shutdown Duty cycle (max) (%) 80
TSSOP (PW) 16 32 mm² 5 x 6.4 WSON (NHQ) 16 25 mm² 5 x 5
  • Internal Start-Up Bias Regulator
  • 3-A Compound Main Gate Driver
  • Programmable Line Undervoltage Lockout (UVLO) With Adjustable Hysteresis
  • Voltage Mode Control With Feedforward
  • Adjustable Dual Mode Overcurrent Protection
  • Programmable Overlap or Dead Time Between the Main and Active Clamp Outputs
  • Volt × Second Clamp
  • Programmable Soft Start
  • Leading Edge Blanking
  • Single Resistor Programmable Oscillator
  • Oscillator UP and DOWN Sync Capability
  • Precision 5-V Reference
  • Thermal Shutdown
  • Packages:
    • 16-Pin TSSOP
    • Thermally Enhanced 16-Pin WSON (5 mm × 5 mm)
  • Internal Start-Up Bias Regulator
  • 3-A Compound Main Gate Driver
  • Programmable Line Undervoltage Lockout (UVLO) With Adjustable Hysteresis
  • Voltage Mode Control With Feedforward
  • Adjustable Dual Mode Overcurrent Protection
  • Programmable Overlap or Dead Time Between the Main and Active Clamp Outputs
  • Volt × Second Clamp
  • Programmable Soft Start
  • Leading Edge Blanking
  • Single Resistor Programmable Oscillator
  • Oscillator UP and DOWN Sync Capability
  • Precision 5-V Reference
  • Thermal Shutdown
  • Packages:
    • 16-Pin TSSOP
    • Thermally Enhanced 16-Pin WSON (5 mm × 5 mm)

The LM5025A is a functional variant of the LM5025 active clamp PWM controller. The functional differences of the LM5025A are that the CS1 and CS2 current limit thresholds have been increased to 0.5 V, the internal CS2 filter discharge device has been disabled and no longer operates each clock cycle, and the internal VCC and VREF regulators continue to operate when the line UVLO pin is below threshold.

The LM5025A PWM controller contains all of the features necessary to implement power converters using the Active Clamp / Reset technique. With the active clamp technique, higher efficiencies and greater power densities can be realized compared to conventional catch winding or RDC clamp / reset techniques. Two control outputs are provided: the main power switch control (OUT_A) and the active clamp switch control (OUT_B). The two internal compound gate drivers parallel both MOS and bipolar devices, providing superior gate drive characteristics. This controller is designed for high-speed operation including an oscillator frequency range up to 1 MHz and total PWM and current sense propagation delays less than 100 ns. The LM5025A includes a high-voltage start-up regulator that operates over a wide input range of 13 V to 90 V. Additional features include: line undervoltage lockout (UVLO), soft start, oscillator UP and DOWN sync capability, precision reference, and thermal shutdown.

The LM5025A is a functional variant of the LM5025 active clamp PWM controller. The functional differences of the LM5025A are that the CS1 and CS2 current limit thresholds have been increased to 0.5 V, the internal CS2 filter discharge device has been disabled and no longer operates each clock cycle, and the internal VCC and VREF regulators continue to operate when the line UVLO pin is below threshold.

The LM5025A PWM controller contains all of the features necessary to implement power converters using the Active Clamp / Reset technique. With the active clamp technique, higher efficiencies and greater power densities can be realized compared to conventional catch winding or RDC clamp / reset techniques. Two control outputs are provided: the main power switch control (OUT_A) and the active clamp switch control (OUT_B). The two internal compound gate drivers parallel both MOS and bipolar devices, providing superior gate drive characteristics. This controller is designed for high-speed operation including an oscillator frequency range up to 1 MHz and total PWM and current sense propagation delays less than 100 ns. The LM5025A includes a high-voltage start-up regulator that operates over a wide input range of 13 V to 90 V. Additional features include: line undervoltage lockout (UVLO), soft start, oscillator UP and DOWN sync capability, precision reference, and thermal shutdown.

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Technical documentation

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Type Title Date
* Data sheet LM5025A Active Clamp Voltage Mode PWM Controller datasheet (Rev. F) PDF | HTML 18 Aug 2016
Technical article Excuse me for being a little forward... with my topology PDF | HTML 21 Oct 2015
User guide LM5025 Isolated Active Clamp Forward Converter Ref Design User Guide 27 Jan 2012
Application note Operation and Benefits of Active-Clamp Forward Power Converters 22 Mar 2007

Design & development

For additional terms or required resources, click any title below to view the detail page where available.

Evaluation board

LM5025AEVAL — Active Clamp Voltage Mode PWM Controller

The LM5025A evaluation board is designed to provide the design engineer with a fully functional power converter based on the Active Clamp Forward topology to evaluate the LM5025A controller. The evaluation board is provided in an industry standard half-brick footprint.

User guide: PDF
Not available on TI.com
Simulation model

LM5025A Unencrypted PSpice Transient Model Package (Rev. A)

SNVM477A.ZIP (48 KB) - PSpice Model
Calculation tool

SLUC655 LM5025A Design Calculator

Supported products & hardware

Supported products & hardware

Products
AC/DC & DC/DC controllers (external FET)
LM5025A 90V active clamp voltage mode PWM controller with P or N-channel clamp FET and 0.5V CS threshold
Reference designs

PMP4468 — 18-V to 36-Vdc input, 5-V/30-W active clamp forward reference design

The PMP4468 is an isolated DC-DC module reference design targeted for industrial and telecom applications. The DC input range is from 18 V to 36 V, with a 24-V typical input and a 5-V, 6-A output. The LM5025A active clamp forward controller is used in the design. The efficiency is up to 90% with (...)
Test report: PDF
Schematic: PDF
Reference designs

PMP4428 — 18-40Vin Isolated 5V/6A Power Supply with Low Profile for Industrial Application Reference Design

This 5V / 6A  solution implements a high efficiency active clamp controller LM5025A and self-drive synchronous rectifier. Input voltage is 18V-40V as typical industrial request and efficiency is 89.5%@24Vin full load. The transformer is embeded into the PCB and 8mm height can be met. The (...)
Test report: PDF
Schematic: PDF
Package Pins CAD symbols, footprints & 3D models
TSSOP (PW) 16 Ultra Librarian
WSON (NHQ) 16 Ultra Librarian

Ordering & quality

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