Overview
The UC3843AM, produced by Microchip Technology, is a fixed frequency current-mode PWM (Pulse Width Modulation) controller. This integrated circuit is specifically designed for off-line and DC to DC converter applications, requiring minimal external components. It is part of the UC3842/UC3843/UC3844/UC3845 family, known for their high performance and versatility in power supply designs.
Key Specifications
| Parameter | Symbol | Value | Unit |
|---|---|---|---|
| Supply Voltage | VCC | 30 | V |
| Output Current | IO | ±1 | A |
| Analog Inputs (Pin 2, 3) | V(ANA) | -0.3 to 6.3 | V |
| Error Amp Output Sink Current | ISINK (E.A) | 10 | mA |
| Power Dissipation at TA≤25°C (8DIP) | PD | 1200 | mW |
| Storage Temperature Range | TSTG | -65 ~ +150 | °C |
| Operating Frequency | f | 47 to 57 | kHz |
| Maximum Duty Cycle | D(Max) | 95 to 100 | % |
| Under-Voltage Lockout Start Threshold | VTH(ST) | 7.8 to 9.0 | V |
Key Features
- Low Start-up Current: Ensures efficient startup with minimal power consumption.
- Maximum Duty Clamp: Allows for precise control over the duty cycle.
- UVLO With Hysteresis: Provides under-voltage lockout with hysteresis for reliable operation.
- Operating Frequency up to 500kHz: Supports high-frequency switching applications.
- Trimmed Oscillator: Offers precise duty cycle control.
- Temperature Compensated Reference: Ensures stable operation over a wide temperature range.
- High Gain Error Amplifier: Enhances the accuracy of feedback control.
- Current Sensing Comparator: Allows for current-mode control.
- High Current Totem-Pole Output: Capable of driving power MOSFETs directly.
Applications
- Off-Line Power Supplies: Suitable for designing power supplies that operate directly from the AC mains.
- DC to DC Converters: Ideal for buck, boost, flyback, and other DC to DC converter topologies.
- High-Frequency Switching Applications: Used in applications requiring high switching frequencies up to 500kHz.
- Power Management Systems: Can be integrated into various power management systems requiring precise control and high efficiency.
Q & A
- What is the UC3843AM used for?
The UC3843AM is used as a fixed frequency current-mode PWM controller for off-line and DC to DC converter applications.
- What is the maximum operating frequency of the UC3843AM?
The UC3843AM can operate at frequencies up to 500kHz.
- What is the under-voltage lockout (UVLO) threshold for the UC3843AM?
The UVLO start threshold for the UC3843AM is between 7.8V and 9.0V.
- What is the maximum duty cycle of the UC3843AM?
The maximum duty cycle of the UC3843AM is between 95% and 100%.
- What type of output does the UC3843AM have?
The UC3843AM has a high current totem-pole output capable of driving power MOSFETs directly.
- What is the power dissipation of the UC3843AM in an 8DIP package?
The power dissipation of the UC3843AM in an 8DIP package is 1200mW at TA≤25°C.
- What is the storage temperature range for the UC3843AM?
The storage temperature range for the UC3843AM is -65°C to +150°C.
- Does the UC3843AM have a temperature compensated reference?
Yes, the UC3843AM features a temperature compensated reference for stable operation over a wide temperature range.
- What type of error amplifier does the UC3843AM have?
The UC3843AM has a high gain error amplifier.
- Can the UC3843AM be used in high-frequency switching applications?
Yes, the UC3843AM is suitable for high-frequency switching applications up to 500kHz.
