SMPS Controller The UC3843N is a high-performance current-mode PWM controller manufactured by STMicroelectronics.
### **Specifications:**
- **Input Voltage (VCC):** 8V to 30V
- **Operating Frequency:** Up to 500 kHz
- **Output Duty Cycle:** 0% to 100%
- **Output Current (Source/Sink):** ±200 mA (Peak)
- **Reference Voltage (VREF):** 5V ±1%
- **Error Amplifier Gain Bandwidth:** 1 MHz
- **Low Startup Current:** <1 mA
- **Undervoltage Lockout (UVLO):** 8V (on) / 7.6V (off)
- **Operating Temperature Range:** -40°C to +85°C
- **Package:** 8-pin DIP (PDIP), SOIC
### **Descriptions:**
The UC3843N is a fixed-frequency pulse-width modulation (PWM) controller optimized for DC-DC converter applications. It features current-mode control for improved loop response and simplified compensation. The device includes a trimmed oscillator, temperature-compensated reference, high-gain error amplifier, and a totem-pole output stage for driving power MOSFETs.
### **Features:**
- **Current-Mode Control:** Provides inherent line feedforward, cycle-by-cycle current limiting, and simplified feedback loop compensation.
- **Automatic Feedforward Compensation:** Ensures consistent response to input voltage variations.
- **Pulse-by-Pulse Current Limiting:** Enhances system reliability.
- **Trimmed Oscillator with Precision Reference:** Ensures accurate frequency control.
- **Undervoltage Lockout (UVLO):** Ensures proper startup and shutdown behavior.
- **High-Current Totem-Pole Output:** Directly drives power MOSFETs.
- **Low Startup and Operating Current:** Reduces power consumption.
The UC3843N is commonly used in offline and DC-DC converters, power supplies, and battery chargers.
