Key Selection Information
| Selection Parameter | Confirmed Information |
|---|---|
| PoE Role | IEEE 802.3at Type-2 powered-device interface |
| PD Current | Up to 0.85 A continuous through internal switch |
| Hotswap | 100 V internal MOSFET, about 0.5 Ω |
| Inrush / Limit | 140 mA inrush; 1 A typical operating current limit |
| Type-2 Support | Hardware classification and T2P status output |
| Auxiliary Input | APD input gives external adapter priority |
| Package | SO PowerPAD (DDA), 8 pins |
| Packing | 2500-piece large tape and reel |
Product Overview
TPS2378DDAR is a PoE powered-device front-end controller, not an Ethernet PHY. It implements IEEE 802.3at Type-2 detection/classification and the high-voltage hotswap path that sits between the Ethernet power interface and the downstream DC/DC converter.
Its internal 100 V pass MOSFET and PowerPAD package support up to 0.85 A continuous PD current. APD allows an external adapter to take priority; when APD is asserted the PoE pass path is disabled and the controller changes its status signaling so the downstream converter can transition sources deliberately.
Correct categorization matters for both customers and search structure: this device belongs with PoE Controllers rather than Ethernet Transceivers because it manages Ethernet-delivered power, not the Ethernet data physical layer.
For related devices, see HKEQGOO’s PoE Controllers category.

Technical Specifications
| Parameter | Verified Information |
|---|---|
| Manufacturer | Texas Instruments |
| Exact MPN | TPS2378DDAR |
| PoE Role | IEEE 802.3at Type-2 powered-device interface |
| PD Current | Up to 0.85 A continuous through internal switch |
| Hotswap | 100 V internal MOSFET, about 0.5 Ω |
| Inrush / Limit | 140 mA inrush; 1 A typical operating current limit |
| Type-2 Support | Hardware classification and T2P status output |
| Auxiliary Input | APD input gives external adapter priority |
| Package | SO PowerPAD (DDA), 8 pins |
| Packing | 2500-piece large tape and reel |
| Manufacturer Status | Active / Production |
| Part Marking | 2378 |
Functional Highlights
APD enables explicit source-priority behavior
A design that accepts both PoE and a local adapter must define which source wins and at what voltage. TPS2378 can disable the PoE hotswap path from APD instead of relying only on passive OR-ing.
Type-2 power depends on the complete PD path, not only the interface IC
The controller can recognize Type-2 operation and carry high current, but bridge loss, cable input voltage, bulk capacitance, converter efficiency and thermal layout still determine usable output power.
Design Considerations
- Use the PowerPAD layout and copper area for hotswap MOSFET heat removal at high PD current.
- Set APD divider thresholds so source handover does not occur at an unusably low adapter voltage.
- Keep detection/classification components and input bridge layout consistent with the IEEE PD interface requirements.
Product Status and Exact Order Code
Manufacturer status: Active / Production
Texas Instruments lists TPS2378DDAR as Active / Production; SO PowerPAD (DDA), 8 pins; 2500-piece large tape and reel; Level-2-260C-1 YEAR; −40°C to +85°C; marking 2378.
Related Engineering Resources
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