Overview
The UC3825N is a high-speed PWM (Pulse Width Modulation) controller IC produced by Texas Instruments. It is part of the UC1825 family, optimized for high-frequency switched mode power supply applications. This controller is designed to operate in either voltage-mode or current-mode systems, with features that minimize propagation delays and maximize bandwidth and slew rate of the error amplifier.
The UC3825N is particularly suited for off-line applications and features advanced protection circuitry, including under-voltage lockout, pulse-by-pulse current limiting, and soft start/max duty cycle control. The device is available in a 16-pin PDIP (N) package and operates within a temperature range of 0°C to 70°C.
Key Specifications
| Parameter | Value | Units |
|---|---|---|
| Supply Voltage | 30 | V |
| Output Current (Source or Sink) | 0.5 | A (DC), 1.5A (Peak) |
| Operating Temperature Range | 0 to 70 | °C |
| Propagation Delay to Output | 50 to 80 | ns |
| Duty Cycle Range | 0 to 85 | % |
| Under-Voltage Lockout Start Threshold | 8.8 to 9.2 | V |
| UVLO Hysteresis | 0.4 to 0.8 | V |
| Start Up Current | 1.1 | mA |
Key Features
- Compatible with Voltage or Current Mode Topologies
- Practical Operation Switching Frequencies to 1MHz
- 50ns Propagation Delay to Output
- High Current Dual Totem Pole Outputs (1.5A Peak)
- Wide Bandwidth Error Amplifier
- Fully Latched Logic with Double Pulse Suppression
- Pulse-by-Pulse Current Limiting
- Soft Start / Max. Duty Cycle Control
- Under-Voltage Lockout with Hysteresis
- Low Start Up Current (1.1mA)
Applications
The UC3825N is ideal for high-frequency switched mode power supply applications, including off-line power supplies, DC-DC converters, and other high-performance power management systems. Its features make it particularly suitable for applications requiring high reliability, low noise, and efficient power conversion.
Q & A
- What is the operating temperature range of the UC3825N?
The UC3825N operates within a temperature range of 0°C to 70°C.
- What is the maximum supply voltage for the UC3825N?
The maximum supply voltage is 30V.
- What is the peak output current capability of the UC3825N?
The UC3825N can source or sink up to 1.5A peak current.
- What is the propagation delay to output for the UC3825N?
The propagation delay to output is between 50ns and 80ns.
- Does the UC3825N support both voltage and current mode topologies?
- What is the duty cycle range of the UC3825N?
The duty cycle range is from 0 to 85%.
- What is the under-voltage lockout start threshold for the UC3825N?
The under-voltage lockout start threshold is between 8.8V and 9.2V.
- What is the start-up current of the UC3825N?
The start-up current is 1.1mA.
- Does the UC3825N have pulse-by-pulse current limiting?
- What is the purpose of the soft start pin in the UC3825N?
The soft start pin doubles as a maximum duty cycle clamp and helps in gradual startup to prevent inrush currents.
