Texas Instruments UC3526AN

The UC3526AN is a high-performance monolithic pulse-width modulator (PWM) circuit designed by Texas Instruments. It is part of the UC3526 series, which is optimized for various power control applications, including fixed-frequency switching regulators. This device is characterized for operation from 0°C to +70°C, making it suitable for a wide range of industrial and commercial environments.

The UC3526AN integrates several key components, including a temperature-compensated voltage reference, a sawtooth oscillator, an error amplifier, pulse width modulation logic, and dual low-impedance power drivers. It also features protective mechanisms such as soft-start, under-voltage lockout, digital current limiting, and double pulse suppression.

• Precision Band-Gap Reference: Internally trimmed to ±1% accuracy, providing a stable 5V reference voltage.
• Wide Operating Voltage Range: Operates from 8V to 35V, with the ability to function at 5V for logic-level applications.
• High Frequency Oscillator: Capable of frequencies from 1 Hz to 400 kHz, programmable with external resistors and capacitors.
• Dual Output Drivers: Source and sink up to 100 mA continuously and 200 mA peak, with minimal cross-conduction current.
• Protective Features: Includes soft-start, under-voltage lockout, digital current limiting, and double pulse suppression logic.
• TTL/CMOS Compatible Logic Ports: Bi-directional ports compatible with TTL and 5V CMOS logic, allowing for flexible control and interfacing.
• Programmable Deadtime and Soft-Start: Adjustable deadtime and soft-start capabilities to customize the device's operation according to application needs.

The UC3526AN is versatile and can be used in various power control applications, including:

• Fixed-Frequency Switching Regulators: Ideal for designing high-efficiency switching power supplies.
• Single-Ended and Push-Pull Switching Regulators: Can be configured for both transformerless and transformer-coupled designs.
• Power Control Systems: Suitable for motor control, lighting systems, and other applications requiring precise power management.
• Industrial and Commercial Power Supplies: Given its operating temperature range, it is suitable for a wide range of industrial and commercial environments.

1. What is the operating voltage range of the UC3526AN?

   The UC3526AN operates from 8V to 35V.

2. What is the frequency range of the oscillator in the UC3526AN?

   The oscillator frequency range is from 1 Hz to 400 kHz.

3. What are the key protective features of the UC3526AN?

   The device includes soft-start, under-voltage lockout, digital current limiting, and double pulse suppression logic.

4. How does the under-voltage lockout feature work in the UC3526AN?

   The under-voltage lockout circuit disables the output drivers and holds the RESET pin LOW if the supply voltage is too low, preventing spurious output pulses.

5. Can the UC3526AN be used in high-temperature environments?

   The UC3526AN is characterized for operation from 0°C to +70°C.

6. What is the accuracy of the reference voltage in the UC3526AN?

   The reference voltage is internally trimmed to ±1% accuracy.

7. How do the output drivers of the UC3526AN perform?

   The output drivers can source and sink up to 100 mA continuously and 200 mA peak, with minimal cross-conduction current.

8. Are the logic ports of the UC3526AN compatible with TTL and CMOS logic?

   Yes, the logic ports are bi-directional and compatible with TTL and 5V CMOS logic.

9. Can the deadtime and soft-start be programmed in the UC3526AN?

   Yes, the deadtime and soft-start can be adjusted according to application needs.

10. What types of switching regulators can be implemented using the UC3526AN?

    The device can be used to implement single-ended or push-pull switching regulators of either polarity, both transformerless and transformer-coupled.