110-V active clamp current mode PWM controller with P-channel clamp FET and line OV protection


Product details


Topology Active-Clamp Forward, Forward Control method Current Supply voltage (Min) (V) 8.5 Supply voltage (Max) (V) 16 Duty cycle (Max) (%) 74 UVLO thresholds on/off (V) 12.7/~8 Frequency (Max) (kHz) 1000 Operating temperature range (C) -40 to 125 Gate drive (Typ) (A) 2 Features HV Start-up, Input Line Monitor, Programmable Slope Compensation, Soft Start, Soft Switching, Supports PFET Clamp Rating Catalog open-in-new Find other PWM controllers & resonant controllers

Package | Pins | Size

TSSOP (PW) 20 42 mm² 6.5 x 6.4 VQFN (RGP) 20 16 mm² 4 x 4 open-in-new Find other PWM controllers & resonant controllers


  • Low-output jitter
  • Soft-stop shutdown of MAIN and AUX
  • 110-V input startup function
  • Ideal for active-clamp, reset-forward, flyback and synchronous rectifier uses
  • Provides complementary auxiliary driver with programmable dead time (Turn-On Delay) between AUX and MAIN switches
  • Peak current-mode control with 0.5-V cycle-by-cycle current limiting
  • TrueDrive™ 2-A Sink, 2-A source outputs
  • Trimmed internal-bandgap reference for accurate line UV and line OV threshold
  • Programmable slope compensation
  • High-performance 1-MHz synchronizable oscillator with internal timing capacitor
  • Precise programmable maximum duty cycle
  • PB-free lead finish package
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The UCC2897A PWM controller simplifies implementation of the various active clamp or reset and synchronous rectifier switching power topologies.

The UCC2897A is a peak current-mode fixed-frequency high-performance pulse-width modulator. The controller includes the logic and the drive capability for the P-channel auxiliary switch along with a simple method of programming the critical delays for proper active-clamp operation.

Features include an internal programmable slope compensation circuit, precise DMAX limit, and a synchronizable oscillator with an internal-timing capacitor. An accurate line-monitoring function also programs the ON and OFF transitions of the converter with regard to the bulk input voltage, VIN.

The UCC2897A adds a second-level hiccup-mode current-sense threshold, bi-directional synchronization and input-overvoltage protection functionalities. The UCC2897A is offered in 20-pin TSSOP (PW) and 20-pin QFN (RGP) packages.

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Technical documentation

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Type Title Date
* Data sheet UCC2897A Advanced Current-Mode Active-Clamp PWM Controller datasheet (Rev. G) Jan. 27, 2019
Application note Understanding and Designing an Active Clamp Current Mode Controlled Converter (Rev. A) Jan. 27, 2020
Selection guide Power Management Guide 2018 (Rev. R) Jun. 25, 2018
Application note Slope Compensation Design for UCC2897A Oct. 30, 2017
Technical article Flyback converters: two outputs are better than one Nov. 24, 2016
Technical article Excuse me for being a little forward... with my topology Oct. 21, 2015
Application note UCC2897A Peak Current Mode Active Clamp Forward Converter Small Signal Modeling Jan. 17, 2014
Technical article MHz isolated power supply - we are at the inflection point Dec. 14, 2013
Application note External Slope Compensation for UCC2897A in Some Special Applications Jan. 05, 2010
Application note Method of Providing Hiccup Operation for UCC2897AEVM Aug. 27, 2009
User guide Using the UCC2897AEVM Feb. 27, 2009
More literature Seminar 1000 Topic 3 - Active Clamp and Reset Technique Feb. 15, 2001
More literature Seminar 1100 Topic 3 - Design Considerations for Active Clamp and Reset Feb. 15, 2001

Design & development

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

Hardware development

document-generic User guide

The TPS2372 evaluation module (TPS2372-4EVM-006) contains evaluation and reference circuitry for the TPS2372, which is a IEEE802.3bt PoE PD controller suitable for high power PoE PD applications such as LED lighting and modules.

In need of an IEEE802.3bt-ready PSE controller? Check out the TPS23880 (...)

  • IEEE802.3bt compliant PoE PD
  • Automatic MPS
  • Inrush Delay
  • AutoClass
document-generic User guide

The TPS2373 evaluation module (TPS2373-4EVM-758) contains evaluation and reference circuitry for the TPS2373, which is a IEEE802.3bt PoE PD controller suitable for high power PoE PD applications. The EVM is designed with a 5V active clamp forward isolated converter for high efficiency, 70W PD (...)

  • IEEE802.3bt-ready PoE PD
  • 5V/14A High Efficiency Active Clamp Converter
  • Automatic MPS
  • Advanced Startup
document-generic User guide

The UCC2897A evaluation module (EVM) is an active clamp reset forward converter providing a 3.3-V regulated output at 30 A of load current, operating from a 48-V input. The design operates over the full 36-V to 72-V telecom input range, and is able to fully regulate down to zero load current. The (...)

  • ZVS transformer reset using active clamp technique in forward converter.
  • All surface mount components, double sided half brick (2.2 x 2.28 x 0.5).
  • Low-side active clamp with programmable dead time for ZVS.
  • Current-Mode Control with bi-directional sync function.
  • Internal PWM slope compensation.
  • Start up (...)

Design tools & simulation

SLUM429.ZIP (122 KB) - PSpice Model
SLUM604.ZIP (43 KB) - TINA-TI Spice Model
SLUM605.TSC (5104 KB) - TINA-TI Reference Design
SLUM606.TSC (2323 KB) - TINA-TI Reference Design
SLUC662A.ZIP (102 KB)

Reference designs

Many TI reference designs include the UCC2897A Use our reference design selection tool to review and identify designs that best match your application and parameters.

CAD/CAE symbols

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QFN (RGP) 20 View options
TSSOP (PW) 20 View options

Ordering & quality

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