RT9742EGJ5F

Overview

The RT9742EGJ5F is a single-channel high-side power switch IC designed for USB applications. It features an N-MOSFET with a maximum on-resistance of 70 mΩ and supports output currents ranging from 0.5 A to 3 A depending on the specific variant configuration. The device operates within a supply voltage range of 2.7 V to 6 V and includes integrated protection circuits such as over-current, thermal shutdown, and under-voltage lockout. It utilizes a TSOT-23-5 package and provides a flag output for fault indication.

Feature Summary

• Integrates over-current protection with short fold-back circuitry
• Includes thermal shutdown and under-voltage lockout mechanisms
• Provides a status flag output to indicate fault conditions
• Features embedded delay function to prevent inrush current mis-operation

Applications

• USB peripheral power switching
• Notebook PC power distribution
• Portable electronic device load switching

Procurement Notes

Verify the exact suffix against the manufacturer datasheet to confirm current rating and package type. Ensure compatibility with existing PCB footprint and thermal requirements. Confirm RoHS compliance status for regulatory adherence. Check moisture sensitivity level for storage and handling procedures.

Selection Notes

Select based on required load current and on-resistance specifications. Consider the TSOT-23-5 package for space-constrained designs. Evaluate the need for the flag output feature for system monitoring. Verify operating temperature range suitability for the intended environment.

Part Context

The RT9742 series comprises cost-effective low-voltage high-side switches optimized for USB interfaces. These ICs combine low conduction losses with comprehensive protection features. The family offers flexibility through various current ratings and package options, making them suitable for diverse portable electronics and computing applications requiring reliable power management.

Replacement Considerations

Consult official substitution lists for equivalent devices with matching electrical characteristics and pin configurations. Verify that alternative components support the same voltage range and protection features. Ensure physical package compatibility for direct replacement without PCB redesign.

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 mis-operation caused by inrush current.