RT9742EGJ5

Overview

The RT9742EGJ5 is a single-channel, low-voltage N-MOSFET high-side power switch IC designed for USB applications. It features a maximum on-resistance of 70 mΩ and supports an output current of 1 A. The device operates within a supply voltage range of 2.7 V to 6 V and includes integrated protection circuits such as over-current protection, short fold-back, thermal shutdown, and under-voltage lockout. An embedded delay function prevents inrush current issues, while a flag output indicates fault conditions.

Feature Summary

• Integrates comprehensive fault protection including over-current, short circuit, thermal shutdown, and UVLO.
• Provides a status flag output to signal fault conditions to the local controller.
• Features an embedded delay function to prevent misoperation caused by inrush currents.

Applications

• USB power supply distribution
• Portable electronic devices
• Peripheral power switching

Procurement Notes

Verify the specific suffix against official Richtek documentation to confirm the exact current rating and package variant. Ensure compatibility with the target PCB footprint and thermal requirements. Confirm RoHS compliance status through the manufacturer's declaration before procurement.

Selection Notes

Select this component when a single-channel high-side switch with integrated fault indication is required. The 1 A current rating and 70 mΩ resistance suit moderate load applications. Consider the TSOT-23-5 package for space-constrained designs requiring surface mount installation.

Part Context

The RT9742 series comprises cost-effective, low-voltage power switches available in multiple current ratings and packages. This model belongs to the family offering integrated protection and status flags, suitable for replacing discrete MOSFET solutions in compact USB-powered systems.

Replacement Considerations

Check datasheets for alternative models like RT9742AGJ5 or RT9742VGJ5 to verify pin compatibility and current ratings. Ensure substitute parts match the required on-resistance and protection thresholds.

FAQ

What is the purpose of the flag output?

The flag output indicates fault conditions, such as over-current or thermal shutdown, to the local USB controller.

Does the device include inrush current protection?

Yes, the chip integrates an embedded delay function to prevent misoperation due to inrush currents.