UC3845B ,PWM Controller IC – SMD, 250kHz Frequency, SOP-8 Package

The UC3845B is a high-performance, fixed-frequency current-mode PWM controller designed for off-line and DC-to-DC converter applications. Housed in a space-saving SOP-8 SMD package, this controller provides fast transient response and cycle-by-cycle current limiting, enhancing the safety and performance of power systems. With its low start-up current, precise oscillator trimming, and integrated UVLO with hysteresis, the UC3845B is ideal for compact, efficient power supply designs. Its totem-pole output stage is capable of sourcing and sinking high peak currents, supporting fast switching and improved power efficiency. It’s widely used in adapters, battery chargers, and other SMPS-based applications.

Key Features:

• Precision trimmed oscillator for accurate frequency control (250 kHz typical).

• Built-in undervoltage lockout (UVLO) with 8.5V on and 7.6V off thresholds.

• Totem-pole output stage capable of sourcing/sinking ±1A peak.

• Internally clamped maximum duty cycle to 50% for enhanced control.

• Low start-up current: typically less than 0.5mA for high-efficiency startup.

• Integrated high-gain error amplifier and current sense comparator.