UC3845NG4

Power Supply Controllers, Monitors Overview

The UC3845NG4 is a current-mode PWM controller manufactured by Texas Instruments, designed for offline and DC-DC converter applications. It operates within a commercial temperature range of 0°C to +70°C and supports Boost, Buck, Flyback, and Forward topologies. The device features a fixed switching frequency capability up to 500 kHz with a maximum duty cycle of 50%. It provides a single output with a peak drive current of 1 A and includes an internal 5 V reference. The component is housed in an 8-pin PDIP package for through-hole mounting.

Power Supply Controllers, Monitors Feature Summary

• Implements current-mode PWM control architecture for enhanced dynamic response and simplified compensation.

Power Supply Controllers, Monitors Applications

• Offline flyback power supplies
• Forward converter designs
• Buck and boost DC-DC converters

Power Supply Controllers, Monitors Procurement Notes

Verify the specific suffix 'G4' indicates lead-free compliance and RoHS status as documented by Texas Instruments. Confirm the PDIP-8 package type matches the target PCB footprint requirements. Ensure the commercial temperature grade aligns with the operational environment specifications before finalizing procurement orders.

Power Supply Controllers, Monitors Selection Notes

Select this component for designs requiring a robust current-mode controller with integrated protection features. The fixed frequency operation simplifies magnetic component selection compared to variable frequency alternatives. Consider the 50% maximum duty cycle limitation when designing high-step-down ratio converters or specific transformer turns ratios.

Power Supply Controllers, Monitors Part Context

This part belongs to the UC384x series of current-mode PWM controllers from Texas Instruments. It shares functional similarities with the UC2845 and UC1845, differing primarily in temperature rating and commercial availability. The series is widely utilized in general-purpose power supply designs due to its established performance characteristics and widespread industry adoption.

Power Supply Controllers, Monitors Replacement Considerations

UC3845N

Power Supply Controllers, Monitors FAQ

What is the maximum switching frequency supported by the UC3845NG4?

The device supports a switching frequency up to 500 kHz, determined by external resistor and capacitor values connected to the RT/CT pin.

Does the UC3845NG4 include overcurrent protection?

Yes, it features per-cycle current limiting that triggers when the voltage at the ISENSE pin exceeds 1 V.