TPS2378DDAR - IEEE 802.3at PoE+ PD Controller 0.85A | TI
N.º de pieza: TPS2378DDAR ✓ Activo| Cant. | Precio unitario | Total |
|---|---|---|
| 1 | $0.7 | $0,70 |
| 10 | $0.63 | $6,30 |
| 100 | $0.55 | $55,00 |
| 500 | $0.49 | $245,00 |
| 1.000 | $0.44 | $440,00 |
TPS2378DDAR Descripción general
A PoE powered device interface is the front-end circuit that lets a network-enabled product safely draw power over the same Ethernet cable that carries its data. Sitting at the top of the power management hierarchy, it performs detection, classification, inrush current limiting and load switching per the IEEE 802.3af and 802.3at standards, before handing a regulated rail to downstream DC-DC converters. The TPS2378 is TI's PD interface controller in that family.
Key features include support for both IEEE 802.3at type-2 (PoE+, up to 25.5 W at the PD) and 802.3af (PoE, class 0-3) operation, an auxiliary power detect (APD) input that gives priority to an external DC supply, and the internal 0.5-ohm pass switch that eliminates a discrete MOSFET. Automatic classification with the CLS pin and a T2P output signal simplify type-2 system designs.
Architecturally, the TPS2378 integrates the IEEE detection and classification state machines, a thermal shutdown, and a gate driver for the internal pass element. The PowerPAD exposed pad on the DDA package provides enhanced thermal dissipation, which is what enables continuous 0.85 A operation through an on-chip switch. The 37-page TI datasheet documents the full state machine timing and threshold levels.
Typical applications include IP security cameras, wireless access points, VoIP phones, PoE lighting (LED) drivers, and networked industrial sensors that must comply with 802.3at type-2 power budgets.
Design-wise, the APD feature allows the PD to prefer a wall-adapter input; tie APD appropriately if auxiliary power is not used. Verify inrush compliance (type-2 class events) during qualification.
This page adds distributor pricing, drop-in alternatives, and practical design guidance beyond the TI datasheet.
Alternativas directas para TPS2378DDAR — mismo encapsulado, compatible pin a pin. Se excluyen las piezas de otro encapsulado que requieren retrabajo de la PCB.
Herramienta de comparación rápida — seleccione piezas alternativas para compararlas lado a lado:
TPS2379DDAR
✅ Sustitución directa ⚠️ Especificaciones sin verificar📋 Alternativa de referencia (no en el catálogo)
TPS2372DDAR
✅ Sustitución directa ⚠️ Especificaciones sin verificar📋 Alternativa de referencia (no en el catálogo)
TPS2373DDAR
✅ Sustitución directa ⚠️ Especificaciones sin verificar📋 Alternativa de referencia (no en el catálogo)
TPS2376DDAR
✅ Sustitución directa ⚠️ Especificaciones sin verificar📋 Alternativa de referencia (no en el catálogo)
TPS2375ADDR
✅ Sustitución directa ⚠️ Especificaciones sin verificar📋 Alternativa de referencia (no en el catálogo)
TPS2378DDAR Valores máximos y características eléctricas
| Función | PoE Powered Device (PD) Interface Controller |
| Standards Supported | IEEE 802.3at Type-2 (PoE+) and IEEE 802.3at Type-1 / 802.3af (PoE) |
| Continuous Switch Current | 0.85 A |
| Internal Switch Resistance | 0.5 ohm |
| Auxiliary Power Detect (APD) | Yes, external supply priority |
| Classification | Class 0-4 via CLS pin |
| Type-2 Present Output | T2P pin |
| Encapsulado | 8-SO PowerPAD (DDA / HSOIC-8-EP) |
| Rango de temperatura de funcionamiento | -40C to +85C |
| Tipo de montaje | Surface Mount |
| Apagado térmico | Yes |
| Recuento de pines | 8 |
| Packaging | Tape & Reel (DDAR suffix) |
| Estado RoHS | Compliant |
| REACH Status | Compliant |
| Typical Power Class | Type-2, up to 25.5 W at PD input |
Configuración de pines de TPS2378DDAR
| Pin 1 | VDD — PoE input supply, diode-bridge negative-rail referenced positive input |
| Pin 2 | RTN — Powered device return / system ground reference after pass switch |
| Pin 3 | T2P — Type-2 present status output, indicates a PoE+ PSE connection |
| Pin 4 | CLS — Classification pin, programs IEEE power class via resistor |
| Pin 5 | APD — Auxiliary power detect input, gives priority to external supply |
| Pin 6 | GATE — Gate drive / pass-element control node |
| Pin 7 | DETC — Detection circuit node for IEEE 802.3 signature |
| Pin 8 | FRSH — Fast resume / related control function node |
| Pin PAD | PowerPAD — Exposed thermal pad, solder to PCB ground plane for heat dissipation |
Aplicaciones típicas
TPS2378DDAR es adecuado para 6 aplicacións: IP Security Cameras, Wireless Access Points, VoIP Phones, PoE LED Lighting Drivers, Industrial Networked Sensors and Controllers, Networked Audio and Intercom Systems.
IP Security Cameras
The TPS2378DDAR is a natural front end for IEEE 802.3at type-2 IP cameras, which commonly draw 12-25 W from a single Ethernet cable. Its 0.85 A continuous rating through the 0.5-ohm internal switch comfortably covers the 25.5 W type-2 budget at nominal 48 V PSE output, while the PowerPAD package keeps thermal rise low inside compact camera housings. The APD auxiliary power detect input lets the camera prefer a local 12 V wall adapter when present, falling back automatically to PoE. Classification signaling on the CLS pin advertises the camera's class so the PoE switch allocates power correctly. Downstream, the controller's RTN output feeds a buck converter for the imager and DSP rails.
Recomendado
Wireless Access Points
Enterprise 802.11ac/ax wireless access points are classic 802.3at type-2 loads, drawing 15-25 W for radio chains plus the host CPU. The TPS2378DDAR provides the compliant PD interface with detection and class advertisement on the CLS pin, and its T2P output lets the access point firmware confirm that a type-2 (PoE+) PSE is connected so it can enable full radio power. The internal 0.5-ohm switch avoids an external pass FET, saving board area in ceiling-mounted enclosures with restricted airflow. The auxiliary power detect input supports AP-powered desk deployments. Thermal performance is aided by the exposed PowerPAD, which should be soldered to a ground pour.
Recomendado
VoIP Phones
VoIP desk phones benefit from the TPS2378DDAR's dual-power architecture: IEEE 802.3at PoE+ from the desk switch, or a local auxiliary adapter with priority via the APD input. Phones are typically Class 2-3 loads, and the CLS pin programs the advertised class so the PBX switch budgets power correctly across many endpoints. The 0.85 A internal switch handles the phone's DC input stage without a discrete MOSFET, and the T2P output allows graceful power-state management when only a type-1 (802.3af) switch is present. Compliance with IEEE detection and classification state machines ensures interoperability across all major PoE switch vendors.
Recomendado
PoE LED Lighting Drivers
Connected LED luminaires increasingly run directly from PoE, and a type-2 (25.5 W) budget covers many downlight and troffer designs. The TPS2378DDAR's 0.85 A continuous current through the 0.5-ohm internal switch accepts the full PSE power, and the PowerPAD (DDA) package dissipates switch and inrush losses reliably in enclosed fixtures where ambient temperatures can reach 85C, the top of the part's rating. The CLS pin advertises the fixture class during IEEE classification, and the APD input allows emergency-lighting fixtures to prefer a battery-backed auxiliary source. The controller's inrush limiting satisfies 802.3at type-2 turn-on requirements without extra components.
Recomendado
Industrial Networked Sensors and Controllers
Factory-floor sensors, actuators and edge controllers benefit from single-cable data plus power, and the TPS2378DDAR's -40C to +85C operating range matches industrial temperature requirements. Its IEEE 802.3at type-2 compliance supports power-hungry edge devices such as vision sensors and protocol gateways drawing up to 25.5 W. The 0.5-ohm internal switch minimizes voltage drop at 0.85 A, preserving headroom for the downstream buck converter, while the T2P status output lets firmware adapt performance to available type-2 power. The APD input supports locally powered controllers that fall back to PoE. Reference design PMP10812 from TI shows a Class 2 PD implementation using this controller with the LM5010.
Recomendado
Networked Audio and Intercom Systems
PoE-powered intercoms, paging amplifiers and IP speakers use the TPS2378DDAR to harvest up to 25.5 W over Ethernet, enough for a class-D amplifier stage plus the network processor. The internal 0.5-ohm switch and PowerPAD thermal design limit dissipation during peak audio power, and the 0.85 A continuous rating covers sustained loud passages at full type-2 power. The CLS classification pin lets the head-end amplifier/PSE budget channels correctly across a facility, while the APD auxiliary input enables local power for high-output units with automatic PoE fallback. The T2P output allows firmware to cap output power when connected to an 802.3af-only switch.
Recomendado
Resumen de productos recomendados
Datos de referencia de ingeniería para TPS2378DDAR — comparación, orientación de diseño e información de cumplimiento.
Guía de selección
Comparación con alternativas
| Parámetro | Este producto | TPS2379DDAR | TPS2372DDAR | TPS2376DDAR | TPS2375ADDR |
|---|---|---|---|---|---|
| Package | 8-SO PowerPAD (DDA) | 8-SO PowerPAD (DDA) - same | 8-SO PowerPAD (DDA) - same | 8-SOIC (D) | 8-SOIC (D) |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| PoE Standard | 802.3at Type-2 + 802.3af | 802.3at Type-2 + FRS | 802.3at + advanced features | 802.3af only | 802.3af only |
| Type-2 Present Output (T2P) | Yes | Yes | Equivalent status output | No (802.3af only) | No (802.3af only) |
| Operating Temperature | -40C to +85C | -40C to +85C | -40C to +125C (TJ, check datasheet) | 0C to +70C | 0C to +70C |
Diferenciadores clave
- 802.3at type-2 (PoE+) support with T2P status output (frente a TPS2375ADDR)
- Lower threshold for auxiliary input priority (frente a TPS2379DDAR)
- Internal 0.5-ohm pass switch with PowerPAD thermal design (frente a TPS2376DDAR)
Notas de diseño
The 0.85 A continuous rating depends directly on the PowerPAD being properly soldered. At 0.5 ohm switch resistance and 0.85 A, estimated switch conduction loss is I^2 x R = 0.36 W (estimate; inputs: 0.85 A, 0.5 ohm). Solder the exposed pad to a minimum 2x2 array of thermal vias into a ground pour; without this, junction temperature rise can exceed ratings at full load. Per TI datasheet guidance for the DDA package, verify junction temperature against the -40C to +85C ambient rating in the worst-case enclosure temperature.
If your design does not use auxiliary power, do not leave the APD pin floating - bias it according to the TI datasheet so the controller always treats the PoE input as active. Similarly, the CLS resistor must be chosen for the correct IEEE class: a wrong class resistor causes the PSE to under-allocate power and the PD will fail to boot. During 802.3at type-2 qualification, verify inrush current and detection signature with a PoE conformance tester before submitting to an interop lab.
Place the IEEE-mandated diode bridge and 0.1 uF/10 uF input decoupling within a few millimeters of VDD and RTN, and keep the high-current loop (bridge -> VDD -> internal switch -> RTN -> bridge return) short and wide. Isolate the T2P and CLS signal traces from the switching node of the downstream converter to avoid corrupting classification signaling. The exposed PowerPAD should connect to a quiet system ground, not the switching ground of the DC-DC stage.
Información de cumplimiento
RoHS and REACH compliance per TI product data. Not an automotive-qualified part; intended for networking, industrial and consumer PoE applications.
