UC3843DG4

Power Supply Controllers, Monitors Overview

The UC3843DG4 is a current-mode PWM controller from Texas Instruments, designed for offline and DC-to-DC converter applications. It operates at a switching frequency of 500 kHz with a maximum duty cycle of 100%. The device features a high-current totem-pole output capable of sourcing 1 A and sinking 200 mA. It supports Boost, Buck, Flyback, and Forward topologies. Operating within a supply voltage range of 12 V to 28 V, it functions reliably between 0°C and +70°C. Packaged in an 8-SOIC surface-mount format, it integrates an internally trimmed bandgap reference and under-voltage lockout with hysteresis.

Power Supply Controllers, Monitors Feature Summary

• Pulse-by-pulse current limiting enhances load response characteristics and protects against overcurrent conditions.
• Automatic feed forward compensation stabilizes operation across varying input voltages.
• Double pulse suppression prevents false triggering during rapid switching transitions.
• Low start-up current minimizes power consumption during initial activation phases.

Power Supply Controllers, Monitors Applications

• Offline flyback converters
• Forward converters
• Buck DC-to-DC converters
• Boost DC-to-DC converters

Power Supply Controllers, Monitors Procurement Notes

Verify the specific suffix 'DG4' indicates lead-free construction and RoHS compliance as per Texas Instruments standards. Confirm the SOIC-8 package dimensions match your PCB footprint requirements. Ensure the operating temperature range of 0°C to +70°C aligns with your system's thermal environment. Cross-reference the datasheet revision to confirm pinout compatibility with existing designs.

Power Supply Controllers, Monitors Selection Notes

Select this component when designing single-output converters requiring current-mode control. It is suitable for applications needing up to 500 kHz switching frequencies. Consider the 1 A peak output drive capability for direct gate driving of MOSFETs. Evaluate the 12 V to 28 V supply range against your auxiliary power availability. Compare against UC3842 or UC3844 variants if different feedback pin configurations are required.

Power Supply Controllers, Monitors Part Context

This part belongs to the UC384x family of current-mode PWM controllers. It shares architectural similarities with the UC3842 and UC3844 but differs in internal compensation and feedback pin assignments. The DG4 suffix denotes a green (RoHS compliant) package variant. It serves as a standard solution for cost-sensitive power supplies requiring reliable current-mode regulation.

Power Supply Controllers, Monitors Replacement Considerations

UC3843D: Standard non-RoHS version with identical electrical specifications. UC3843N: PDIP-8 through-hole equivalent for prototyping or high-power thermal dissipation needs. UC1843DG4: Industrial temperature grade (-55°C to +125°C) alternative for harsh environments.

Power Supply Controllers, Monitors FAQ

What is the maximum switching frequency?

The UC3843DG4 is optimized for operation at a switching frequency of 500 kHz.

Does the device include current limiting?

Yes, it features pulse-by-pulse current limiting on the current sense pin to protect the external switch.

What is the output drive capability?

The totem-pole output can source up to 1 A and sink up to 200 mA.