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UCC2897A

ACTIVE

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

Product details

Topology Active-clamp forward Control mode Current Duty cycle (max) (%) 74 Switching frequency (max) (kHz) 1000 Features High-voltage startup, Input line monitor, Programmable slope compensation, Soft start, Soft switching, Supports PFET clamp UVLO thresholds on/off (V) 12.7/8 Operating temperature range (°C) -40 to 125 Rating Catalog Gate drive (typ) (A) 2 Vin (max) (V) 16
Topology Active-clamp forward Control mode Current Duty cycle (max) (%) 74 Switching frequency (max) (kHz) 1000 Features High-voltage startup, Input line monitor, Programmable slope compensation, Soft start, Soft switching, Supports PFET clamp UVLO thresholds on/off (V) 12.7/8 Operating temperature range (°C) -40 to 125 Rating Catalog Gate drive (typ) (A) 2 Vin (max) (V) 16
TSSOP (PW) 20 41.6 mm² 6.5 x 6.4 VQFN (RGP) 20 16 mm² 4 x 4
  • 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
  • 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

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.

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) PDF | HTML 27 Jan 2019
Application note Understanding and Designing an Active Clamp Current Mode Controlled Converter (Rev. A) 27 Jan 2020
Selection guide Power Management Guide 2018 (Rev. R) 25 Jun 2018
Application note Slope Compensation Design for UCC2897A 30 Oct 2017
Technical article Flyback converters: two outputs are better than one PDF | HTML 24 Nov 2016
Technical article Excuse me for being a little forward... with my topology PDF | HTML 21 Oct 2015
Application note UCC2897A Peak Current Mode Active Clamp Forward Converter Small Signal Modeling 17 Jan 2014
Application note External Slope Compensation for UCC2897A in Some Special Applications 05 Jan 2010
Application note Method of Providing Hiccup Operation for UCC2897AEVM 27 Aug 2009
EVM User's guide Using the UCC2897AEVM 27 Feb 2009
More literature Seminar 1000 Topic 3 - Active Clamp and Reset Technique 15 Feb 2001
More literature Seminar 1100 Topic 3 - Design Considerations for Active Clamp and Reset 15 Feb 2001

Design & development

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

Evaluation board

TPS2372-4EVM-006 — TPS2372-4EVM evaluation module for IEEE802.3bt PoE PD applications

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.

User guide: PDF
Not available on TI.com
Evaluation board

TPS2373-4EVM-758 — TPS2373-4 evaluation module for IEEE802.3bt PoE PD applications

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 (...)

User guide: PDF | HTML
Not available on TI.com
Evaluation board

UCC2897AEVM — UCC2897A Evaluation Module

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 (...)

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

UCC2897A PSpice Transient Model

SLUM429.ZIP (122 KB) - PSpice Model
Simulation model

UCC2897A TINA-TI Startup Transient Reference Design

SLUM605.TSC (5104 KB) - TINA-TI Reference Design
Simulation model

UCC2897A TINA-TI Steady State Transient Reference Design

SLUM606.TSC (2323 KB) - TINA-TI Reference Design
Simulation model

UCC2897A TINA-TI Transient Spice Model

SLUM604.ZIP (43 KB) - TINA-TI Spice Model
Calculation tool

SLUC662 UCC2897A Design Calculator

Supported products & hardware

Supported products & hardware

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PWM controllers
UCC2897A 110-V active clamp current mode PWM controller with P-channel clamp FET and line OV protection

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

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