UCC2805N

Overview

The UCC2805N is a discontinued low-power BiCMOS current-mode PWM controller manufactured by Texas Instruments. It operates within a supply voltage range of 10 V to 30 V and supports switching frequencies up to 1 MHz. The device features a maximum duty cycle of 50% and provides an output drive current of 1 A. It is housed in an 8-PDIP package with a pin spacing of 7.62 mm. The operational temperature range spans from -40°C to 125°C. Key electrical characteristics include rise and fall times of 41 ns and 44 ns, respectively.

Feature Summary

• Implements current-mode PWM control architecture for efficient power regulation.
• Integrates internal soft-start functionality to manage inrush currents during startup.
• Includes built-in frequency compensation and slope compensation circuits.
• Features high-voltage startup circuitry for direct connection to bus voltages.

Applications

• Universal AC-DC offline power supplies
• Battery charger applications
• Adapters and external power packs

Procurement Notes

The UCC2805N has been officially declared obsolete by Texas Instruments, with end-of-life notifications issued in March 2022. Procurement is restricted to existing stock or surplus channels only. Verify component authenticity and lot codes carefully when sourcing from third-party distributors, as availability is limited and inconsistent. Designers should prioritize alternative components for new production runs.

Selection Notes

Select this component only for maintenance or legacy system repairs where the original design specification requires exact pinout and electrical compatibility. For new designs, evaluate modern equivalents that offer improved thermal performance or enhanced feature sets. Ensure the selected replacement maintains the required 50% duty cycle limit and current-mode control topology to preserve circuit stability.

Part Context

This part belongs to the UCC280x series of low-power BiCMOS controllers, designed for cost-effective and compact power supply solutions. It shares architectural similarities with other devices in the family but is distinguished by its specific 8-pin DIP packaging and fixed 50% duty cycle limitation. The series targets general-purpose offline converter topologies requiring simple implementation.

Replacement Considerations

UC2845BN (STMicroelectronics) is documented as a similar substitute option.