UC3844 Current-Mode PWM Controller IC DIP-8

Description

UC3844 Current-Mode PWM Controller IC DIP-8 The UC3844 Current-Mode PWM Controller IC DIP-8 is a high-efficiency, fixed-frequency control IC designed for use in switch-mode power supplies and DC-DC converters. It combines all essential power control functions, including an oscillator, precision 5V reference, error amplifier, current-sense comparator, and a high-current totem-pole output stage capable of directly driving power MOSFETs. The UC3844AN features current-mode operation that provides superior line and load regulation, fast transient response, and inherent cycle-by-cycle current limiting. With its low start-up current and high switching frequency, it is ideal for compact and energy-efficient designs. Packaged in a standard 8-pin DIP, this controller is widely used in off-line power supplies, battery chargers, motor control circuits, and DC-DC converter modules. Features Fixed-frequency current-mode PWM control for superior performance. High-speed totem-pole output for driving power MOSFETs or BJTs. Low start-up and operating current for improved efficiency. Accurate 5V ±1% reference voltage for stable operation. Adjustable oscillator frequency for flexible design options. Cycle-by-cycle current limiting for overload protection. Undervoltage lockout (UVLO) with hysteresis for safe startup. High efficiency and fast transient response. Wide operating voltage range: 7.6V to 30V. Standard 8-pin DIP package for easy integration in SMPS and converter circuits. Pinout Configuration Pin No. Symbol Function 1 COMP Compensation input – error amplifier output for loop compensation 2 VFB Feedback input – voltage feedback to internal error amplifier 3 ISENSE Current sense input – detects switch current for PWM control and protection 4 RT/CT Timing resistor and capacitor – sets oscillator frequency 5 GND Ground 6 OUTPUT Output driver – controls external power MOSFET 7 VCC Supply voltage input (7.6 V – 30 V) 8 VREF 5 V precision reference output (up to 20 mA) Dimensions Specifications Parameter Specification Product Type Current-Mode PWM / DC-DC Converter Control IC Part Number UC3844AN Datasheet UC3844 Manufacturer TDSEMIC Package Type DIP-8 Operating Voltage Range 7.6 V – 30 V Reference Voltage 5.0 V ± 2% Oscillation Frequency 500 kHz Output Type Adjustable Topology Supported Buck, Boost, Flyback, Forward Number of Channels 1 Switch Type External MOSFET Undervoltage Lockout (UVLO) Start: 8.4V – Stop: 6.9 V Output Drive Capability ±1 A peak Optimization Optimized for multi-topology power supplies including buck, boost, and buck-boost Maximum Duty Cycle 48% UVLO Thresholds (Start/Stop) Lower thresholds, suitable for specific design constraints Design Flexibility Provides limited duty cycle for improved control and efficiency Control Method Fixed-frequency peak current-mode PWM Main Application Low-Voltage, DC-DC Converters, Discontinuous Flyback, High-Efficiency Converters Operating Temperature Range 0 °C – +70 °C Applications Switch-Mode Power Supplies (SMPS). DC-DC Converter Circuits. Battery Chargers and Power Adapters. LED Drivers and Lighting Power Supplies. Motor Speed Control Systems. Inverter and Converter Modules. Industrial and Consumer Power Electronics. Offline Flyback and Forward Converter Designs. Package Contents 1 x UC3844 Current-Mode PWM Controller IC DIP-8 Datasheet UC3844

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