UC3845BDTR

The UC3845BDTR is a high-performance, current-mode PWM (Pulse Width Modulation) controller specifically designed for offline and DC-to-DC converter applications. It is manufactured by STMicroelectronics and is part of the UC384xB family of control ICs. This versatile IC provides the necessary features to implement fixed-frequency current-mode control schemes with minimal external components.

Key Features:

1. Fixed-Frequency Operation: The UC3845BDTR operates at a fixed frequency, typically around 250 kHz (guaranteed) to 500 kHz (maximum), which simplifies filter design and reduces component count.
2. Current-Mode Control: The current-mode control architecture allows for fast transient response and excellent line and load regulation, ensuring stable and reliable power supply operation.
3. Internal Trimmed Oscillator: The IC features an internal trimmed oscillator for precise frequency control, providing consistent performance over a wide range of operating conditions.
4. Precision Reference and Error Amplifier: The precision reference trimmed for accuracy at the error amp input ensures precise regulation of the output voltage.
5. PWM Comparator and Current Limit Control: The PWM comparator provides current limit control, protecting the power supply and load from overcurrent conditions.
6. Totem Pole Output Stage: The totem pole output stage is designed to source or sink high peak currents, making it ideal for driving N-channel MOSFETs in power supply applications.
7. Protective Features: The UC3845BDTR includes protective features such as undervoltage lockout (UVLO) with hysteresis, ensuring safe operation under low-voltage conditions.
8. Compact Packaging: The IC is available in a compact package, such as SOP-8, providing a space-saving solution for PCB integration.

Applications:

The UC3845BDTR is suitable for a wide range of applications, including:

• Offline power supplies
• DC-to-DC converters
• Battery chargers
• LED drivers
• Motor control systems

Operating Conditions:

• Operating Voltage Range: Typically 10V to 35V (or higher, depending on the specific version and application)
• Maximum Operating Temperature: Up to +105°C (with derating above +70°C for some versions)
• Minimum Operating Temperature: Typically -40°C

In summary, the UC3845BDTR is a high-performance PWM controller IC that offers a combination of features making it an excellent choice for a wide range of power supply and motor control applications. Its fixed-frequency operation, current-mode control, and protective features provide robust and reliable performance, while its compact package and low external component count make it easy to integrate into various systems.