A newer version of this product is available

open-in-new Compare products
Drop-in replacement with upgraded functionality to the compared device.
UC3843A ACTIVE 30-V, 1A, 500KHz current mode PWM controller with 8.4V/7.6V UVLO 100% duty cycle 0°C to 70°C Pin-to-pin equivalent with reduced start-up current

Product details

Topology Boost, Buck, Buck-Boost, Flyback, Forward Duty cycle (Max) (%) 100 Supply voltage (Max) (V) 28 UVLO thresholds on/off (V) 8.4/7.6 Features Adjustable Switching Frequency, Current Limiting, Dead Time Control, Error Amplifier, Multi-topology Operating temperature range (C) 0 to 70 Rating Catalog Frequency (Max) (kHz) 500 Gate drive (Typ) (A) 1
Topology Boost, Buck, Buck-Boost, Flyback, Forward Duty cycle (Max) (%) 100 Supply voltage (Max) (V) 28 UVLO thresholds on/off (V) 8.4/7.6 Features Adjustable Switching Frequency, Current Limiting, Dead Time Control, Error Amplifier, Multi-topology Operating temperature range (C) 0 to 70 Rating Catalog Frequency (Max) (kHz) 500 Gate drive (Typ) (A) 1
PDIP (P) 8 93 mm² 9.81 x 9.43 SOIC (D) 14 52 mm² 8.65 x 6 SOIC (D) 8 19 mm² 3.91 x 4.9
  • Optimized for off-line and DC-to-DC converters
  • Low start-up current (< 1 mA)
  • Automatic feedforward compensation
  • Pulse-by-pulse current limiting
  • Enhanced load-response characteristics
  • Undervoltage lockout with hysteresis
  • Double-pulse suppression
  • High-current totem-pole output
  • Internally trimmed bandgap reference
  • Up to 500-kHz operation
  • Error amplifier with low output resistance
  • Optimized for off-line and DC-to-DC converters
  • Low start-up current (< 1 mA)
  • Automatic feedforward compensation
  • Pulse-by-pulse current limiting
  • Enhanced load-response characteristics
  • Undervoltage lockout with hysteresis
  • Double-pulse suppression
  • High-current totem-pole output
  • Internally trimmed bandgap reference
  • Up to 500-kHz operation
  • Error amplifier with low output resistance

The UCx84x series of control integrated circuits provide the features that are necessary to implement off-line or DC-to-DC fixed-frequency current-mode control schemes, with a minimum number of external components. The internally implemented circuits include an undervoltage lockout (UVLO), featuring a start-up current of less than 1 mA, and a precision reference trimmed for accuracy at the error amplifier input. Other internal circuits include logic to ensure latched operation, a pulse-width modulation (PWM) comparator that also provides current-limit control, and a totem-pole output stage that is designed to source or sink high-peak current. The output stage, suitable for driving N-channel MOSFETs, is low when it is in the off state.

The UCx84x family offers a variety of package options, temperature range options, choice of maximum duty cycle, and choice of turnon and turnoff thresholds and hysteresis ranges. Devices with higher turnon or turnoff hysteresis are ideal choices for off-line power supplies, while the devices with a narrower hysteresis range are suited for DC-DC applications. The UC184x devices are specified for operation from –55°C to 125°C, the UC284x series is specified for operation from –40°C to 85°C, and the UC384x series is specified for operation from 0°C to 70°C.

The UCx84x series of control integrated circuits provide the features that are necessary to implement off-line or DC-to-DC fixed-frequency current-mode control schemes, with a minimum number of external components. The internally implemented circuits include an undervoltage lockout (UVLO), featuring a start-up current of less than 1 mA, and a precision reference trimmed for accuracy at the error amplifier input. Other internal circuits include logic to ensure latched operation, a pulse-width modulation (PWM) comparator that also provides current-limit control, and a totem-pole output stage that is designed to source or sink high-peak current. The output stage, suitable for driving N-channel MOSFETs, is low when it is in the off state.

The UCx84x family offers a variety of package options, temperature range options, choice of maximum duty cycle, and choice of turnon and turnoff thresholds and hysteresis ranges. Devices with higher turnon or turnoff hysteresis are ideal choices for off-line power supplies, while the devices with a narrower hysteresis range are suited for DC-DC applications. The UC184x devices are specified for operation from –55°C to 125°C, the UC284x series is specified for operation from –40°C to 85°C, and the UC384x series is specified for operation from 0°C to 70°C.

Download

Technical documentation

star = Top documentation for this product selected by TI
No results found. Please clear your search and try again.
View all 16
Type Title Date
* Data sheet UCx84x Current-Mode PWM Controllers datasheet (Rev. F) 28 Apr 2020
Application note Conditioning a Switch-mode Power Supply Current Signal Using TI Op Amps (Rev. A) 11 Jun 2021
Application note Understanding Inverting Buck-Boost Power Stages in Switch Mode Power Supplies (Rev. B) 12 Mar 2019
Selection guide Power Management Guide 2018 (Rev. R) 25 Jun 2018
Technical article When should you use PWM controllers? 02 Dec 2016
Application note UCC38C42 Family of High-Speed BiCMOS Current-Mode PWM Controllers 07 Feb 2002
Application note DN-26 UC3842A Low-Cost Start-up and Fault Protection Circuit 05 Sep 1999
Application note DN-27 UC1842/UC1842A Family - Summary of Functional Differences 05 Sep 1999
Application note DN-40 The Effects of Oscillator Discharge Current Variations on Maximum Duty 05 Sep 1999
Application note DN-42A Design Considerations for Transitioning from UC3842 to the New UCC3802 05 Sep 1999
Application note DN-43 Simple Techniques to Generate a Negative Voltage Bias Supply 05 Sep 1999
Application note DN-65 Considerations in Powering BiCMOS ICs 05 Sep 1999
Application note U-100A UC3842/3/4/5 Provides Low-Cost Current-Mode Control 05 Sep 1999
Application note U-111, Practical Considerations in Current Mode Power Supplies 05 Sep 1999
Application note Understanding Boost Power Stages In Switchmode Power Supplies 04 Mar 1999
Application note Understanding Buck Power Stages In Switchmode Power Supplies 04 Mar 1999

Design & development

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

Simulation model

UCC28C43 PSpice Transient Model

SLUM033.ZIP (101 KB) - PSpice Model
Simulation model

UCCx8C43 Unencrypted PSpice Transient Model

SLUM521.ZIP (4 KB) - PSpice Model
Package Pins Download
PDIP (P) 8 View options
SOIC (D) 14 View options
SOIC (D) 8 View options

Ordering & quality

Information included:
  • RoHS
  • REACH
  • Device marking
  • Lead finish/Ball material
  • MSL rating/Peak reflow
  • MTBF/FIT estimates
  • Material content
  • Qualification summary
  • Ongoing reliability monitoring

Recommended products may have parameters, evaluation modules or reference designs related to this TI product.

Support & training

TI E2E™ forums with technical support from TI engineers

Content is provided "as is" by TI and community contributors and does not constitute TI specifications. See terms of use.

If you have questions about quality, packaging or ordering TI products, see TI support. ​​​​​​​​​​​​​​

Videos