TPS2371D

Specialized Overview

The TPS2371D is a legacy IEEE 802.3af compatible power interface switch for Powered Devices (PDs). It operates within an input voltage range of 44 V to 57 V and supports an operating junction temperature from 0°C to 70°C. The device incorporates a precision UVLO with a 20-ms off-time delay, programmable inrush current limiting, and internal thermal protection. An internal low-side FET provides a typical on-resistance of 0.3 Ω. Classification levels are set via external resistors corresponding to Class 0 through Class 4.

Specialized Feature Summary

• Performs detection, classification, and inrush current limiting for IEEE 802.3af compatibility
• Interfaces directly with DC/DC converter enable or soft-start pins
• Includes internal thermal shutdown that disconnects the load upon overheating

Specialized Applications

• VoIP Phones
• Internet Appliances
• Wireless LAN Access Points
• Bluetooth Access Points

Specialized Procurement Notes

Verify the specific package suffix against the datasheet ordering information. The 'D' suffix indicates an 8-pin Plastic SOIC package. Confirm the required tape and reel quantity if mass production is intended, as standard packaging may differ from single-unit procurement.

Specialized Selection Notes

Select this component for designs requiring strict compliance with legacy IEEE 802.3af standards. Ensure the application utilizes an external resistor network to program the inrush current limit if load capacitance exceeds 180 µF. Verify that the system operates within the specified 0°C to 70°C ambient temperature range.

Specialized Part Context

This part belongs to the TPS237x family of PoE controllers. It serves as the primary interface between the Power Sourcing Equipment (PSE) and the Powered Device (PD), handling the protocol handshake before passing power to downstream DC/DC converters.

Specialized Replacement Considerations

Public confirmed substitute part numbers include TPS2371PW and TPS2371DR. These variants share identical electrical characteristics but differ in package type (TSSOP vs. SOIC) or shipping configuration (Reel vs. Tube).

Specialized FAQ

How is the inrush current limited?

The inrush current is programmed by connecting an external resistor (RLIM) from the ILIM pin to the VEE pin. This allows designers to accommodate load capacitances larger than the 180 µF limit defined by the standard.

What is the function of the EN_DC pin?

The EN_DC pin acts as a control output for the connected DC/DC converter. It sinks 80 µA during startup to hold the converter off until the load capacitor is charged, then transitions to high impedance to allow normal soft-start operation.

How does the device handle thermal faults?

If the junction temperature reaches the thermal shutdown threshold, the internal FET switches off to remove the load. The device will automatically retry after cooling; if the fault persists, it latches off after seven cycles.