Product details


Topology Boost, Flyback, Forward Control method Current VCC (Min) (V) 12 VCC (Max) (V) 25 Duty cycle (Max) (%) 100 UVLO thresholds on/off (V) 8.4/7.6 Frequency (Max) (kHz) 500 Operating temperature range (C) -55 to 125 Gate drive (Typ) (A) 1 Features Error Amplifier, Multi-topology Rating Space open-in-new Find other PWM controllers & resonant controllers

Package | Pins | Size

CDIP (JG) 8 - CFP (HKU) 10 - LCCC (FK) 20 - open-in-new Find other PWM controllers & resonant controllers


  • QML Class V (QMLV) Qualified, SMD 5962-86704
  • 5962P8670409Vxx:
    • Radiation Hardness Assurance (RHA) up to
      30-krad(Si) Total Ionizing Dose (TID)
    • Passes Functional and Specified Post-Radiation Parametric Limits at 45 krad at LDR (10 mrad(Si)/s) per 1.5× Over Test as Defined in MIL-STD-883 Test Method 1019.9 Paragraph 3.13.3.b
    • Exhibits Low-Dose Rate Sensitivity but Remains Within the Pre-Radiation Electrical Limits at 30-krad Total Dose Level, as Allowed by MIL-STD-883, TM1019
  • Optimized for Offline and DC-to-DC Converters
  • Low Start-Up Current (< 0.5 mA)
  • Trimmed Oscillator Discharge Current
  • Automatic Feed Forward Compensation
  • Pulse-by-Pulse Current Limiting
  • Enhanced Load Response Characteristics
  • Undervoltage Lockout (UVLO) With Hysteresis
  • Double-Pulse Suppression
  • High-Current Totem-Pole Output
  • Internally-Trimmed Bandgap Reference
  • 500-kHz Operation
  • Low RO Error Amplifier

All trademarks are the property of their respective owners.

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The UC1843A-SP control IC is a radiation hardened pin-for-pin compatible version of the UC184x family. Providing the necessary characteristics to control current-mode switched-mode power supplies, this device has improved features. Start-up current is specified to be less than 0.5 mA and oscillator discharge is trimmed to 8.3 mA. During UVLO, the output stage can sink at least 10 mA at less than 1.2 V for VCC over 5 V.

The Device Comparison Table shows the difference between members of this family. Reference the individual product data sheets for ordering the radiation-improved version if available.

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Technical documentation

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Type Title Date
* Datasheet UC1843A-SP QML class V, radiation hardened current-mode PWM controller datasheet (Rev. A) Feb. 21, 2019
Radiation & Reliability reports Heavy Ion Orbital Environment Single-Event Effects Estimations May 18, 2020
Radiation & Reliability reports Single-Event Effects Confidence Interval Calculations Jan. 14, 2020
More literature Preview: Radiation Handbook for Electronics (Rev. A) Jun. 07, 2019
Solution guides Radiation Handbook for Electronics (Rev. A) May 21, 2019
Selection guides TI Space Products (Rev. G) May 15, 2019
SMD UC1843A-SP SMD 5962-86704 Jul. 08, 2016
Technical articles Power Tips: Calculate an R-C snubber in seven steps May 05, 2016
Radiation & Reliability reports UC1843A-SP Radiation Test Report May 11, 2015
Application notes UCC38C42 Family of High-Speed BiCMOS Current-Mode PWM Controllers Feb. 07, 2002
Application notes DN-26 UC3842A Low-Cost Start-up and Fault Protection Circuit Sep. 05, 1999
Application notes DN-27 UC1842/UC1842A Family - Summary of Functional Differences Sep. 05, 1999
Application notes DN-29 UC3842A Family - Frequency Foldback Technique Provides Protection Sep. 05, 1999
Application notes DN-30 Programmable Electronic Circuit Breaker Sep. 05, 1999
Application notes DN-40 The Effects of Oscillator Discharge Current Variations on Maximum Duty Sep. 05, 1999
Application notes DN-62 Switching Power Supply Topology Voltage Mode vs. Current Mode Sep. 05, 1999
Application notes DN-65 Considerations in Powering BiCMOS ICs Sep. 05, 1999
Application notes DN-89 Comparing the UC3842, UCC3802, and UCC3809 Primary Side PWM Controllers Sep. 05, 1999
Application notes Modeling, Analysis and Compensation of the Current-Mode Converter Sep. 05, 1999
Application notes U-100A UC3842/3/4/5 Provides Low-Cost Current-Mode Control Sep. 05, 1999
Application notes U-111, Practical Considerations in Current Mode Power Supplies Sep. 05, 1999

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 UC1843BEVM-CVAL uses the UC1843A-SP, INA901-SP, LM139AQML-SP, and UC1901-SP to create an isolated feedback flyback with current sensing and over current flags. The UC1843A-SP is used to switch the low side MOSFET of the flyback converter and provide voltage and current to the output. The (...)
  • PWM control using UC1843B-SP
  • Over current comparison using LM139AQML-SP
  • Current sensing using INA901-SP

Design tools & simulation

SLUM660.ZIP (3 KB) - PSpice Model
SLUM661.ZIP (105 KB) - PSpice Model
SLUM674.TSC (6331 KB) - TINA-TI Reference Design
SLUM675.ZIP (17 KB) - TINA-TI Spice Model

Reference designs

20- to 40-VIN, 50-W Space-grade isolated flyback DC/DC over-current protection reference design
TIDA-070002 — Spacecraft bus voltages vary from the well-established 28-V to more than the 100-V typically used in highpower commercial communications satellites, this reference design shows an example for a space-grade 50-W isolated intermediary bus converter, while implementing over-current protection (OCP (...)
document-generic Schematic document-generic User guide

CAD/CAE symbols

Package Pins Download
CDIP (JG) 8 View options
CFP (HKU) 10 View options
LCCC (FK) 20 View options

Ordering & quality

Support & training

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