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Texas Instruments TPS2370DR
- Part No.:
- TPS2370DR
- Manufacturer:
- Texas Instruments
- Category:
- Specialized
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
TPS2370DR.pdf
- Description:
- IC INTERFACE SPECIALIZED 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,992
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Product details
Overview
TPS2370DR from Texas Instruments is an IEEE 802.3af-compliant Power over Ethernet (PoE) powered device (PD) interface IC with integrated 0.3-Ω low-side FET, programmable inrush current limit (50–449 mA), UVLO turn-on at 40.2 V, and thermal shutdown at 144 °C. It performs PD detection, classification (Class 0–4), and hot-swap control for VoIP phones and wireless LAN access points.
For engineers reviewing the TPS2370DR datasheet, TPS2370DR pinout, TPS2370DR application, or TPS2370DR equivalent, key selection considerations include its 8-pin TSSOP package, 48–57 V operating input range, 0.3 Ω RDS(on), EN_DC soft-start interface, and compatibility with both voltage- and current-based classification schemes.
Technical Context
The TPS2370DR implements a state-machine-controlled PoE front-end: detection (1.8–10 V, <12 µA sleep current), classification (14–20.5 V, precision 10-V reference on CLASS pin), inrush mode (>40 V rising edge, ILIM-programmable current), and normal operation (>30 V, 0.3-Ω FET conduction). Its internal UVLO hysteresis (8.8 V) ensures stable transition between states.
It integrates a 80-µA EN_DC current sink that holds off DC/DC soft-start until load voltage reaches within 1.5 V of final value, eliminating need for external UVLO in downstream converters. Thermal protection latches off after seven retries under sustained overload, requiring power cycle for reset.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 48–57 V nominal; supports IEEE 802.3af PSE output with 40.2 V UVLO turn-on and 31.4 V turn-off. |
| RDS(on) | 0.3 Ω typical; enables high-efficiency power delivery to downstream DC/DC converter with minimal I²R loss. |
| Inrush Current Limit | Programmable 50–449 mA via ILIM-to-VEE resistor; removes 180 µF capacitor limitation per IEEE 802.3af. |
| Classification Support | Class 0–4 via single RCLASS resistor; uses internal 10-V reference for accurate current sourcing during 15–20 V classification window. |
| EN_DC Function | 80-µA current sink active during startup; delays DC/DC soft-start until VRTN is within 1.5 V of target, preventing premature regulation. |
| Thermal Protection | 144 °C shutdown with 20 °C hysteresis; cycles up to 7 times before latching off - requires power recycle to recover. |
| Detection Signature | Valid 24.9-kΩ resistance across DET–VDD; draws 73 µA at 1.8 V and 390 µA at 9.5 V for reliable PSE recognition. |
Pinout & Package
TPS2370DR is housed in an 8-pin TSSOP (PW) package with 0.65-mm lead pitch and 1.2-mm max height, optimized for compact PoE front-end layouts and compatible with standard reflow profiles (MSL Level-1).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| ILIM (1) | Inrush current programming output | Connects to VEE via resistor to set startup current limit (50–449 mA); avoids oscillation with >100 pF capacitance. |
| CLASS (2) | Classification current source | Supplies precise 10-V reference during classification; RCLASS sets Class 0–4 current (2.5–39.6 mA) per IEEE 802.3af Table 1. |
| DET (3) | Detection load connection | Interface point for 24.9-kΩ RDET; forms valid PD signature (70–400 µA) recognized by PSE during 1.8–10 V probing. |
| VEE (4) | Negative supply return | Common ground reference for controller logic, CLASS, DET, ILIM, and EN_DC; not connected to load return path. |
| RTN (5) | Load return path drain | Drain terminal of internal low-side FET; connects to DC/DC input return; carries full load current with 0.3-Ω conduction. |
| EN_DC (6) | DC/DC enable/soft-start interface | Open-drain output sinking 80 µA until VRTN reaches target – used to delay DC/DC soft-start without external circuitry. |
| NC (7) | No connect | Internally unused; must be left floating or tied to VEE per layout guidelines to avoid noise coupling. |
| VDD (8) | PoE input positive rail | Accepts 48–57 V PSE output; supplies internal LDOs and UVLO comparator; withstands 68 V absolute max. |
Key Features
| Feature | Design Value |
|---|---|
| IEEE 802.3af Detection & Classification | Fully autonomous compliance: 24.9-kΩ detection signature + Class 0–4 resistor-programmed current sourcing. |
| Programmable Inrush Current Limit | External RLIM resistor sets 50–449 mA limit, enabling >180 µF input capacitance without violating IEEE 802.3af 400-mA/50-ms rule. |
| Integrated Low-Side Power Switch | 0.3-Ω RDS(on) FET eliminates external MOSFET; reduces BOM count and PCB area while maintaining >95% efficiency at 400 mA. |
| EN_DC Soft-Start Coordination | 80-µA current sink replaces discrete UVLO circuitry; synchronizes DC/DC startup with PoE rail stabilization, avoiding brownout resets. |
| Thermal Fault Management | Hysteretic 144 °C shutdown with auto-retry (7×) and latch-off behavior prevents thermal runaway in short-circuit conditions. |
Applications
| VoIP Phones | Wireless LAN Access Points |
|---|---|
Use Scenario: Powered via Category 5 Ethernet cabling in enterprise desk phones with local DC/DC conversion to 3.3 V and 1.2 V rails. IC Role / Device Role / Timing Role: Primary PoE interface IC handling detection, classification, inrush limiting, and hot-swap FET control. Use Value: Enables single-cable deployment without local AC adapter; programmable inrush allows large hold-up capacitors for talk-time continuity during brief cable disconnects. |
Use Scenario: Midspan or endspan-powered 802.11a/b/g/n access points with dual-band RF sections and Ethernet backhaul. IC Role / Device Role / Timing Role: IEEE 802.3af PD controller managing power sequencing and fault isolation between PSE and DC/DC stage. Use Value: Eliminates need for external current-sense resistors and discrete gate drivers; EN_DC coordination prevents RF section lockup during PoE ramp-up. |
| Bluetooth Access Points | Internet Appliances |
Use Scenario: Compact Bluetooth mesh gateways deployed in smart building infrastructure with PoE-powered sensors and controllers. IC Role / Device Role / Timing Role: Low-quiescent-power PD interface supporting detection down to 1.8 V and classification up to 20.5 V. Use Value: Ultra-low sleep current (<12 µA) ensures reliable detection even with long cable drops and high series resistance. |
Use Scenario: Networked home automation hubs (e.g., Zigbee-to-Ethernet bridges) requiring robust PoE startup under variable ambient temperatures. IC Role / Device Role / Timing Role: Integrated PoE front-end with thermal shutdown and UVLO hysteresis for unattended operation. Use Value: 20 °C thermal hysteresis prevents chatter during transient overloads; 8.8 V UVLO hysteresis avoids oscillation near PSE voltage limits. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar PoE powered device interface applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS2371DR | Includes integrated 100-V avalanche-rated FET; higher RDS(on) (0.5 Ω); same pinout and feature set. | Better surge tolerance for outdoor or industrial PoE deployments with high-transient risk. | Select TPS2371DR when system-level surge testing exceeds IEC 61000-4-5 Level 3; otherwise TPS2370DR suffices for indoor Class 0–4 applications. |
| LT4275IMS#PBF | Linear Technology part with 0.25-Ω RDS(on), wider 36–60 V input range, and built-in 100-V clamp diode. | Supports legacy 36-V PSEs and offers tighter classification current accuracy (±2%) vs. TPS2370DR's ±5%. | Choose LT4275IMS#PBF for designs requiring extended input range or tighter classification tolerance; TPS2370DR remains optimal for cost-sensitive, standard 48–57 V deployments. |
Compared with TPS2370DR, TPS2371DR adds 100-V FET ruggedness at the cost of higher conduction loss, while LT4275IMS#PBF extends input range and improves classification accuracy but increases BOM cost and footprint - TPS2370DR delivers best balance of integration, efficiency, and IEEE 802.3af compliance for mainstream indoor PoE endpoints.
Availability
TPS2370DR is available at Aetrix Electronics and suitable for VoIP phones, wireless LAN access points, Bluetooth access points, and internet appliances requiring stable component supply across industrial temperature ranges and multi-year production cycles.
Supply support for TPS2370DR includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Texas Instruments is a global semiconductor company headquartered in Dallas, Texas, delivering analog and embedded processing solutions for industrial, automotive, and communications markets.
The TPS2370DR belongs to TI's Power over Ethernet (PoE) Powered Device Interface product line, engineered specifically to simplify IEEE 802.3af-compliant endpoint design with minimal external components and robust thermal and electrical protection.
FAQ
What is the function of the EN_DC pin on the TPS2370DR?
The EN_DC pin on the TPS2370DR is an open-drain output that sinks 80 µA during PoE startup to delay DC/DC converter soft-start until the load voltage reaches within 1.5 V of its final value. This eliminates the need for external UVLO circuitry and ensures clean power sequencing. Once the condition is met, the TPS2370DR releases EN_DC, allowing the downstream DC/DC converter to ramp normally. The TPS2370DR's EN_DC behavior is integral to its seamless integration with off-the-shelf DC/DC controllers.
Does the TPS2370DR support all IEEE 802.3af power classes?
Yes, the TPS2370DR supports IEEE 802.3af Classes 0 through 4 via a single external resistor (RCLASS) connected between the CLASS pin and VEE. Each class corresponds to a defined resistance value (e.g., 4.42 kΩ for Class 0, 255 Ω for Class 4), and the TPS2370DR applies a precise 10-V reference to generate the required classification current (2.5–39.6 mA). The TPS2370DR does not support Class 4 for production use per TI documentation, as it is reserved for future standards - Class 0–3 are fully validated and recommended.
What is the maximum continuous load current the TPS2370DR can deliver?
The TPS2370DR supports a continuous load current up to 455 mA (typical) with its internal 0.3-Ω low-side FET, as specified in the "Full load current limit" parameter under Electrical Characteristics. This rating assumes operation within the recommended junction temperature range (0–70 °C), adequate PCB copper area for thermal dissipation, and input voltage ≥30 V. Exceeding this current triggers thermal shutdown or current limiting - the TPS2370DR is not rated for >500 mA sustained operation.
Can the TPS2370DR operate with input voltages below 48 V?
Yes, the TPS2370DR operates across the full IEEE 802.3af input range: detection begins at 1.8 V, classification activates between 14–20.5 V, and normal FET conduction starts at 40.2 V UVLO turn-on. It functions reliably down to 30 V in normal operation mode. While nominal PSE output is 48–57 V, the TPS2370DR accommodates voltage drop across long cables or barrel rectifiers - confirmed by TI's specification of detection down to 1.3 V and classification latching below 14 V. The TPS2370DR maintains full functionality across this extended operational envelope.
How does the TPS2370DR implement inrush current limiting?
The TPS2370DR implements programmable inrush current limiting via the ILIM pin: connecting an external resistor (RLIM) from ILIM to VEE sets the startup current using the equation IINRUSH = 450 mA − (25 kΩ / RLIM) × 1 A, yielding a range of 50–449 mA. This replaces fixed 400-mA limits, enabling larger input capacitors (>180 µF) without violating IEEE 802.3af. The TPS2370DR's ILIM circuit actively regulates current during the initial FET turn-on phase, reducing stress on upstream magnetics and cabling - a core capability distinguishing the TPS2370DR from non-programmable PoE controllers.
TPS2370DR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Applications:
- Power Interface Switch for Power Over Ethernet (PoE) Devices
- Interface:
- IEEE 802.3af
- Voltage - Supply:
- -
- Supplier Device Package:
- 8-SOIC
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
TPS2370DR FAQ
1.How can I place an order for TPS2370DR through Aetrix?
Please submit a Request for Quotation (RFQ) for TPS2370DR on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for TPS2370DR reliable?
The price and inventory of TPS2370DR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TPS2370DR is usually 5 days.
3.What payment methods are accepted for TPS2370DR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TPS2370DR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TPS2370DR?
TPS2370DR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TPS2370DR order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for TPS2370DR?
For technical support, including TPS2370DR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TPS2370DR requirements.
6.How does Aetrix verify that TPS2370DR is sourced from the original manufacturer or authorized distributors?
All TPS2370DR products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that TPS2370DR meets industry standards.
7.What is the process for return or replacement of TPS2370DR?
All TPS2370DR units undergo pre-shipment inspection (PSI). If there is an issue with TPS2370DR, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The TPS2370DR part is unused and in its original packaging.
Return procedure for TPS2370DR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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