Overview
The UC3842AN is a fixed-frequency, current-mode PWM (Pulse Width Modulation) controller produced by Texas Instruments. It is part of the UCx84xA family, which is an improved version of the UCx84x family. This controller is designed for off-line and DC-DC converter applications, offering enhanced features and performance. The UC3842AN is known for its low start-up current, trimmed oscillator discharge current, and high-current totem-pole output, making it a versatile and efficient choice for various power supply designs.
Key Specifications
| Parameter | Value | Unit |
|---|---|---|
| Supply Voltage | Up to 30 | V |
| Output Current | Up to 1 | A |
| Operating Frequency | Up to 500kHz | |
| Operating Temperature Range | 0°C to 70°C | |
| UVLO Thresholds | 16V (on), 10V (off) | V |
| Package Type | PDIP (P) - 8 pins | |
| Maximum Duty Cycle | 100% | % |
| Start-Up Current | < 0.5mA | mA |
| Oscillator Discharge Current | 8.3mA | mA |
Key Features
- Optimized for Off-Line and DC-DC Converters
- Low Start-Up Current (< 0.5mA)
- Trimmed Oscillator Discharge Current
- Automatic Feedforward Compensation
- Pulse-by-Pulse Current Limiting
- Enhanced Load Response Characteristics
- Undervoltage Lockout With Hysteresis
- Double Pulse Suppression
- High-Current Totem Pole Output
- Internally-Trimmed Bandgap Reference
- Up to 500kHz Operation
Applications
The UC3842AN is specifically designed for off-line and DC-DC converter applications. It is suitable for a wide range of power supply designs where high efficiency, reliability, and minimal external components are required. These applications include but are not limited to:
- Switched-mode power supplies
- DC-DC converters
- Off-line power supplies
Q & A
- What is the operating frequency range of the UC3842AN?
The UC3842AN can operate up to 500kHz. - What is the start-up current of the UC3842AN?
The start-up current is less than 0.5mA. - What are the UVLO thresholds for the UC3842AN?
The UVLO thresholds are 16V (on) and 10V (off). - What is the maximum duty cycle of the UC3842AN?
The maximum duty cycle is 100%. - What type of package does the UC3842AN come in?
The UC3842AN comes in a PDIP (P) package with 8 pins. - What is the operating temperature range of the UC3842AN?
The operating temperature range is 0°C to 70°C. - Does the UC3842AN have pulse-by-pulse current limiting?
Yes, the UC3842AN features pulse-by-pulse current limiting. - What is the purpose of the internally-trimmed bandgap reference in the UC3842AN?
The internally-trimmed bandgap reference provides a stable voltage reference for the controller. - Can the UC3842AN be used in life support devices or systems?
No, the UC3842AN is not authorized for use as critical components in life support devices or systems without the express written approval of the manufacturer. - How does the UC3842AN handle undervoltage lockout?
The UC3842AN features undervoltage lockout with hysteresis to prevent the controller from operating below a certain voltage threshold.
