EmbeddedRelated.com
    Parts    UC3843BN
UC3843BN

UC3843BN

STMicroelectronics
Boost, Flyback Regulator Positive, Isolation Capable Output Step-Up, Step-Up/Step-Down DC-DC Controller IC 8-Mini DIP
Active3,074 in stock
Datasheet Digi-Key Mouser Compare Prices

Overview

The UC3843BN is a high-performance current mode PWM controller specifically designed for off-line and DC-to-DC converter applications. It features a trimmed oscillator for precise duty cycle control and an internally trimmed reference with undervoltage lockout optimized for lower voltage thresholds. This controller is capable of driving a single power MOSFET via its high-current totem pole output, supporting up to 96 percent duty cycle.

Why Choose This Part

The UC3843BN offers a high-current totem pole output capable of sourcing or sinking 1A peak current, facilitating fast switching of power MOSFETs. Its current-mode architecture provides excellent line regulation and simplified loop compensation while protecting the system via latching PWM for cycle-by-cycle current limiting.

Applications

DC-to-DC Boost Converters
Efficiently steps up lower DC input voltages to higher stable output voltages in battery-powered systems.
Isolated Flyback Power Supplies
Used in AC-DC or DC-DC isolated power stages where small size and simple control loops are required.
Current-Mode Power Modules
Ideal for modules requiring cycle-by-cycle current limiting and automatic feed-forward compensation.

Key Specifications

Function Step-Up, Step-Up/Step-Down
Topology Boost, Flyback
Clock Sync No
Output Type Transistor Driver
Mounting Type Through Hole
Output Phases 1
Package / Case 8-DIP (0.300", 7.62mm)
Control Features Frequency Control
Duty Cycle (Max) 96%
Number of Outputs 1
Output Configuration Positive, Isolation Capable
Frequency - Switching Up to 500kHz
Operating Temperature 0degC ~ 70degC (TJ)
Synchronous Rectifier No
Supplier Device Package 8-Mini DIP
Voltage - Supply (Vcc/Vdd) 7.6V ~ 30V

Getting Started

To begin development, design a PCB around the 8-pin DIP footprint and utilize the internal reference and oscillator to set your desired switching frequency. Ensure proper bypass capacitors are placed near the VCC pin to handle the 12mA operating current and high-speed switching transients.

UC3843 Family

Comparing specs that differ across variants. The current part is highlighted.

Part Number Topology Output Type Package Duty Cycle (Max) Temp Range Stock
UC3843BN (this part) Boost, Flyback Transistor Driver DIP-8 96% 0degC ~ 70degC (TJ) 3,074
UC3843AD8TR (Texas Instruments) Tape & Reel Boost, Buck, Flyba.. PWM SOIC-8 100% 0degC ~ 70degC (TA) 2,335
UC3843AN (Texas Instruments) — — DIP-8 — 0degC ~ 70degC (TA) 7,586