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UC3844BD1R2G

ONUC3844BD1R2G

onsemi
Boost, Flyback Regulator Positive, Isolation Capable Output Step-Up, Step-Up/Step-Down DC-DC Controller IC 8-SOIC
Active9,240 in stock
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Overview

The UC3844BD1R2G is a high-performance current-mode PWM controller designed for off-line and DC-to-DC converter applications. It provides the necessary features to implement control of boost and flyback topologies with a minimal external parts count. This specific variant is AEC-Q100 qualified, making it suitable for automotive and high-reliability power systems.

Why Choose This Part

The controller features a trimmed oscillator for precise frequency control and a high-current totem pole output capable of driving power MOSFETs directly. Its current-mode architecture provides inherent cycle-by-cycle current limiting and excellent input voltage feed-forward compensation. The low startup current of 300 microamps and undervoltage lockout with hysteresis ensure reliable operation in sensitive power-up sequences.

Applications

Off-line Flyback Converters
Used in isolated AC-DC power supplies for consumer and industrial electronics where a 50 percent duty cycle limit is required.
Automotive DC-DC Converters
AEC-Q100 qualification allows use in vehicle power management and auxiliary power systems.
Boost Regulators
Efficiently steps up lower input voltages to a higher regulated output for specialized sensor or drive circuitry.

Key Specifications

Function Step-Up, Step-Up/Step-Down
Topology Boost, Flyback
Clock Sync No
Output Type Transistor Driver
Mounting Type Surface Mount
Output Phases 1
Package / Case 8-SOIC (0.154", 3.90mm Width)
Control Features Frequency Control
Duty Cycle (Max) 48%
Number of Outputs 1
Output Configuration Positive, Isolation Capable
Frequency - Switching Up to 500kHz
Operating Temperature 0degC ~ 70degC (TA)
Synchronous Rectifier No
Supplier Device Package 8-SOIC
Voltage - Supply (Vcc/Vdd) 10V ~ 36V

Getting Started

To begin development, reference the standard application circuits for flyback or boost topologies in the datasheet, ensuring the VDD supply remains within the 36V maximum limit. Since this is an analog controller, use SPICE simulation tools to model the feedback loop compensation and verify the 48 percent maximum duty cycle meets your design requirements. Prototype using the 8-SOIC footprint on a dedicated PCB with short traces to the sense resistor to minimize switching noise.

Also Consider

UC3842BD1R2G ONonsemi - Supports up to 100 percent duty cycle for applications where the 50 percent limit of the UC3844 is restrictive.