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UCC38C45

ACTIVE

Commercial, 20-V, low-power current-mode PWM controller, 8.4-V/7.6-V UVLO, 50% duty cycle

Product details

Topology Boost, Buck, Flyback, Forward, SEPIC Control mode Current Duty cycle (max) (%) 50 Switching frequency (max) (kHz) 1000 Features Adjustable switching frequency, Current limiting, Dead time control, Error amplifier, Multi-topology, Programmable max duty cycle UVLO thresholds on/off (V) 8.4/7.6 Operating temperature range (°C) 0 to 85 Rating Catalog Gate drive (typ) (A) 1 Vin (max) (V) 18
Topology Boost, Buck, Flyback, Forward, SEPIC Control mode Current Duty cycle (max) (%) 50 Switching frequency (max) (kHz) 1000 Features Adjustable switching frequency, Current limiting, Dead time control, Error amplifier, Multi-topology, Programmable max duty cycle UVLO thresholds on/off (V) 8.4/7.6 Operating temperature range (°C) 0 to 85 Rating Catalog Gate drive (typ) (A) 1 Vin (max) (V) 18
SOIC (D) 8 29.4 mm² 4.9 x 6 VSSOP (DGK) 8 14.7 mm² 3 x 4.9
  • Enhanced replacement for UCx84x and UCx84xA family with pin-to-pin compatibility
  • Operating frequency: 1 MHz Maximum
  • 50-µA Startup Current, 100-µA Maximum
  • Low operating current: 2.3 mA (at fOSC = 52 kHz)
  • Fast, cycle-by-cycle overcurrent limiting: 35-ns
  • Peak driving current: ±1-A. Rail-to-rail output:
    • 25-ns rise time
    • 20-ns fall time
  • ±1% accurate 2.5-V error amplifier reference
  • Trimmed oscillator discharge current
  • Undervoltage lockout protections
  • VSSOP-8 package minimizes board space
  • Enhanced replacement for UCx84x and UCx84xA family with pin-to-pin compatibility
  • Operating frequency: 1 MHz Maximum
  • 50-µA Startup Current, 100-µA Maximum
  • Low operating current: 2.3 mA (at fOSC = 52 kHz)
  • Fast, cycle-by-cycle overcurrent limiting: 35-ns
  • Peak driving current: ±1-A. Rail-to-rail output:
    • 25-ns rise time
    • 20-ns fall time
  • ±1% accurate 2.5-V error amplifier reference
  • Trimmed oscillator discharge current
  • Undervoltage lockout protections
  • VSSOP-8 package minimizes board space

The UCCx8C4x family are high-performance, current-mode PWM controllers. The UCCx8C4x is an enhanced BiCMOS version with pin-for-pin compatibility to the industry standard UCx84xA family and UCx84x family of PWM controllers. The BiCMOS technology offers lower power consumption to improve efficiency as well as faster current sense and oscillator frequency.

In addition, lower startup voltage versions of 7 V are offered as UCCx8C40 and UCCx8C41 for use in battery systems. The UCC28C4x series is specified for operation from –40°C to 125°C, and the UCC38C4x series is specified for operation from 0°C to 85°C.

Providing necessary features to control fixed frequency, peak current-mode power supplies, this family offers the following performance advantages. The device offers high-frequency operation up to 1 MHz, suitable for high speed applications. The trimmed discharge current enables more precise programming of the maximum duty cycle and dead-time limit when compared to the UCCx8C4x family. Reduced start-up and operating currents minimizes start-up loss and low operating power consumption for improved efficiency. The device also features a fast current-sense-to-output delay time of 35 ns for superior overload protection at the power switch, and a ±1-A peak output current capability with improved rise and fall times for driving large external MOSFETs directly.

The UCCx8C4x family is offered in 8-pin VSSOP (DGK) and 8-pin SOIC (D) packages.

The UCCx8C4x family are high-performance, current-mode PWM controllers. The UCCx8C4x is an enhanced BiCMOS version with pin-for-pin compatibility to the industry standard UCx84xA family and UCx84x family of PWM controllers. The BiCMOS technology offers lower power consumption to improve efficiency as well as faster current sense and oscillator frequency.

In addition, lower startup voltage versions of 7 V are offered as UCCx8C40 and UCCx8C41 for use in battery systems. The UCC28C4x series is specified for operation from –40°C to 125°C, and the UCC38C4x series is specified for operation from 0°C to 85°C.

Providing necessary features to control fixed frequency, peak current-mode power supplies, this family offers the following performance advantages. The device offers high-frequency operation up to 1 MHz, suitable for high speed applications. The trimmed discharge current enables more precise programming of the maximum duty cycle and dead-time limit when compared to the UCCx8C4x family. Reduced start-up and operating currents minimizes start-up loss and low operating power consumption for improved efficiency. The device also features a fast current-sense-to-output delay time of 35 ns for superior overload protection at the power switch, and a ±1-A peak output current capability with improved rise and fall times for driving large external MOSFETs directly.

The UCCx8C4x family is offered in 8-pin VSSOP (DGK) and 8-pin SOIC (D) packages.

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Technical documentation

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Type Title Date
* Data sheet UCCx8C4x BiCMOS Low-Power Current-Mode PWM Controller datasheet (Rev. H) PDF | HTML 16 Sep 2022
Functional safety information UCCx8C4x Functional Safety, FIT Rate, Failure Mode Distribution and Pin FMA PDF | HTML 12 Sep 2022
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 UCC38C44 12-V Isolated Bias Supply (Rev. A) 09 Oct 2008
User guide UCC38C42 30-W Synchronous Buck Converter Reference Design 04 Feb 2003
Application note UCC38C42 25-W Forward Converter 06 Sep 2002
Application note UCC38C42 Family of High-Speed BiCMOS Current-Mode PWM Controllers 07 Feb 2002
More literature Seminar 300 Topic 8 - Switching Power Supply Design Review 15 Feb 2001
More literature Seminar 400 Topic 2 - Design of Flyback Transformers and Filter Inductors 15 Feb 2001
More literature Seminar 900 Topic 6 - High Power Factor Prereg Using SEPIC 15 Feb 2001
Application note DN-30 Programmable Electronic Circuit Breaker 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.

Evaluation board

UCC28C56EVM-066 — UCC28C56H-Q1 evaluation module for primary-side controlled (with AUX winding) flyback regulator

The UCC28C56EVM-066 is a highly efficient primary-side controlled (with AUX winding) flyback auxiliary power supply for EV and HEV automotive power trains. The design provides 15.2-VTYP, 40-W output for 800-V battery systems. It will deliver 40 W over the input voltage range from 125 V to 1000 V. (...)

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

UCCx8C45 Unencrypted PSpice Transient Model

SLUM533.ZIP (5 KB) - PSpice Model
Reference designs

PMP10834 — 85-265Vin, 5Vout, 1Aout, AC-DC Fly-Buck Converter Reference Design

The PMP10834RevA reference design is a compact and thermally efficient design intended to step down a wide range of AC inputs (85VAC to 265VAC). This non-isolated Flybuck design incorporates the UCC28C42 PWM with an optocoupler feedback to provide 1% output voltage regulation. All the circuit (...)
Test report: PDF
Schematic: PDF
Package Pins Download
SOIC (D) 8 View options
VSSOP (DGK) 8 View options

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