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UC3843A

ACTIVE

30-V, 1A, 500KHz current mode PWM controller with 8.4V/7.6V UVLO 100% duty cycle 0°C to 70°C

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Data sheet

UC3843A

ACTIVE
Data sheet Order now

Product details

Rating Catalog Topology Boost, Buck, Flyback, Forward Vin (max) (V) 28 Control mode Current Features Adjustable switching frequency, Current limiting, Dead time control, Error amplifier, Fixed frequency, Multi-topology Operating temperature range (°C) 0 to 70 Duty cycle (max) (%) 100
Rating Catalog Topology Boost, Buck, Flyback, Forward Vin (max) (V) 28 Control mode Current Features Adjustable switching frequency, Current limiting, Dead time control, Error amplifier, Fixed frequency, Multi-topology Operating temperature range (°C) 0 to 70 Duty cycle (max) (%) 100
PDIP (P) 8 92.5083 mm² 9.81 x 9.43 SOIC (D) 8 29.4 mm² 4.9 x 6 SOIC (D) 14 51.9 mm² 8.65 x 6
  • Optimized for Off-Line and DC-DC Converters
  • Low Start-Up Current (< 0.5mA)
  • Trimmed Oscillator Discharge Current
  • 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 500kHz Operation
  • Create a Custom Design Using the UCx84xA With the WEBENCH Power Designer
  • Optimized for Off-Line and DC-DC Converters
  • Low Start-Up Current (< 0.5mA)
  • Trimmed Oscillator Discharge Current
  • 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 500kHz Operation
  • Create a Custom Design Using the UCx84xA With the WEBENCH Power Designer

The UCx84xA family of control devices is a pin-for-pin compatible improved version of the UCx84x family. Providing the necessary features to control current-mode or switched-mode power supplies, this family of devices has many improved features: startup current is less than 0.5mA, oscillator discharge is trimmed to 8.3mA, and during UVLO, the output stage can sink at least 10mA at less than 1.2V for VCC over 5V.

The UCx84xA family of control devices is a pin-for-pin compatible improved version of the UCx84x family. Providing the necessary features to control current-mode or switched-mode power supplies, this family of devices has many improved features: startup current is less than 0.5mA, oscillator discharge is trimmed to 8.3mA, and during UVLO, the output stage can sink at least 10mA at less than 1.2V for VCC over 5V.
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Technical documentation

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Type Title Date
* Data sheet UCx84xA Current-Mode PWM Controller datasheet (Rev. H) PDF | HTML 11 Oct 2024
Application note Conditioning a Switch-mode Power Supply Current Signal Using TI Op Amps (Rev. A) PDF | HTML 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
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-29 UC3842A Family - Frequency Foldback Technique Provides Protection 05 Sep 1999
Application note DN-30 Programmable Electronic Circuit Breaker 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 U-111, Practical Considerations in Current Mode Power Supplies 05 Sep 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
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Simulation model

UCCx8C43 Unencrypted PSpice Transient Model

SLUM521.ZIP (4 KB) - PSpice Model
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Package Pins CAD symbols, footprints & 3D models
PDIP (P) 8 Ultra Librarian
SOIC (D) 8 Ultra Librarian
SOIC (D) 14 Ultra Librarian
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