UC3842 - SMD/SMT Current Mode PWM Controller SMD-8 (SOIC-8) - LM3842 / TL3842

The UC3842 is a fixed-frequency current-mode PWM controller designed for low- to medium-power switch-mode power supplies (SMPS). Packaged in an SMD-8 (SOIC-8) surface-mount format, it integrates high-performance analog control circuitry for precise duty cycle control, fast response, and high efficiency in power conversion systems such as flyback or forward converters.

Key Features & Benefits:

• Current-Mode Control: Enhances line and load regulation with cycle-by-cycle current limiting.

• Fixed Frequency Oscillator: Typically operates at 100 kHz, suitable for compact power designs.

• Low Start-Up Current: Reduces input power requirements and supports efficient start-up.

• Under-Voltage Lockout (UVLO): Optimized threshold (turn-on at ~16V, turn-off at ~10V) for reliable operation.

• SMD-8 (SOIC-8) Package: Compact, surface-mountable, ideal for automated PCB assembly.

Specifications:

• Function: Current Mode PWM Controller

• Package: SMD-8 / SOIC-8

• Operating Voltage (V_CC): 16V to 30V

• UVLO Thresholds:
   – Turn-on: ~16V
   – Turn-off: ~10V

• Oscillator Frequency: Up to 500 kHz (typical use at 100 kHz)

• Reference Voltage: 5V ±1% (internal precision reference)

• Output Drive Capability: ±1A peak

• Start-Up Current: < 1 mA

• Operating Supply Current: ~11 mA

• RoHS Compliant: Yes

Applications:

• Off-line SMPS (flyback, forward converters)

• LED drivers and battery chargers

• DC-DC converters

• Standby power supplies

• Industrial and consumer power modules