High Performance Current Mode Controller The UC3845B is a high-performance current-mode PWM controller manufactured by STMicroelectronics.
### **Specifications:**
- **Input Voltage (VCC):** 8.5V to 30V
- **Operating Frequency:** Up to 500kHz
- **Output Duty Cycle:** 0% to 100%
- **Peak Output Current:** ±1A (sink/source)
- **Reference Voltage (VREF):** 5V ±1%
- **Current Sense Comparator Threshold:** 1V
- **Undervoltage Lockout (UVLO):** On at 8.4V (typ), Off at 7.6V (typ)
- **Operating Temperature Range:** -40°C to +85°C
- **Package Options:** SO-8, PDIP-8
### **Descriptions:**
The UC3845B is a fixed-frequency pulse-width modulation (PWM) controller optimized for high-performance DC-DC converters. It features current-mode control for improved loop response and simplified compensation. The device includes an oscillator, error amplifier, current-sense comparator, and a high-current totem-pole output driver.
### **Features:**
- **Current-Mode Operation:** Provides inherent line feedforward and cycle-by-cycle current limiting.
- **Programmable Oscillator:** Adjustable frequency via external resistor and capacitor.
- **Precision Reference:** 5V bandgap reference with ±1% accuracy.
- **Soft-Start Capability:** Reduces inrush current during startup.
- **Undervoltage Lockout (UVLO):** Ensures proper operation under low-voltage conditions.
- **High-Current Output Driver:** Capable of driving power MOSFETs directly.
- **Low Startup Current:** Typically 0.5mA.
This information is based on STMicroelectronics' official datasheet for the UC3845B.
