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Texas Instruments TPS23731RMTR
- Part No.:
- TPS23731RMTR
- Manufacturer:
- Texas Instruments
- Category:
- Power Over Ethernet (PoE) Controllers
- Package:
- 45-VFQFN Exposed Pad
- Datasheet:
-
TPS23731RMTR.pdf
- Description:
- IEEE 802.3BT TYPE 3 CLASS 1-4 PO
- Quantity:
- Payment:
- Shipping:
Inventory:7,449
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Product details
Overview
TPS23731 from Texas Instruments is an IEEE 802.3bt Type 3 PoE powered device (PD) interface with integrated current-mode flyback DC-DC controller supporting primary-side regulation (PSR), featuring a 100-V, 0.3-Ω hotswap MOSFET, ±1.5% load regulation at 5 V, and operation across –40°C to 125°C junction temperature - deployed in IEEE-compliant VoIP phones and security cameras.
For engineers reviewing the TPS23731 datasheet, TPS23731 pinout, TPS23731 application, or TPS23731 equivalent, this page delivers verified specifications including PSR-enabled flyback control, automatic MPS behavior, soft-stop shutdown, programmable frequency dithering for EMI reduction, and Class 1–4 classification compliance - all confirmed per TI SLVSER7 (October 2020) production data.
Technical Context
The TPS23731 integrates dual functional blocks: an IEEE 802.3bt/at PD interface with auto-stretching Maintain Power Signature (MPS), classification current programming via CLS resistor, and robust 100-V hotswap FET; and a current-mode DC-DC controller optimized for CCM flyback with PSR feedback via CP/FB pins, slope compensation, and synchronous rectification support.
It implements advanced startup with adjustable soft-start (SST capacitor), hiccup-mode overload protection, soft-stop shutdown (I_STP resistor-controlled), and spread-spectrum frequency dithering (DTHR pin) - all operating from a single 48-V PoE input with VDD undervoltage lockout at 37.6 V (typ) and thermal shutdown at 158°C (typ).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| IEEE Compliance | Full 802.3bt Type 3 (Class 1–4) and 802.3at support; EA Gen 2 logo-ready PD controller. |
| Hotswap FET RDS(on) | 0.3 Ω (typ) at 100 V rating - enables robust inrush limiting and low conduction loss in PoE input stage. |
| DC-DC Switching Frequency | 248 kHz (typ), adjustable via FRS resistor - balances efficiency, transformer size, and EMI filter cost. |
| Load Regulation | ±1.5% (typ) at 5-V output over 0–100% load with sync FET; ±3% (typ) at 12-V output with diode rectification. |
| PSR Support | Primary-side regulation enabled via CP/FB/PSRS pins - eliminates optocoupler and shunt regulator, reducing BOM count and board area. |
| MPS Behavior | Auto-adjusts pulsed current amplitude/duration per PSE type (Type 1–2 vs. Type 3–4); no external timing components required. |
| Junction Temperature Range | –40°C to 125°C - qualified for industrial and outdoor IP camera deployments without derating. |
Pinout & Package
VSON-45 package (7.00 mm × 5.00 mm) with exposed thermal pads PAD_G (connected to RTN) and PAD_S (connected to VSS) for enhanced power dissipation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CS | DC-DC current sense input | Direct connection to external sense resistor; sets peak current limit and enables cycle-by-cycle protection. |
| FB | Error amplifier inverting input | Receives PSR feedback from auxiliary winding voltage divider; determines output regulation accuracy and transient response. |
| GATE | High-side MOSFET gate driver output | Drives external flyback switch with 0.5-A peak source / 0.9-A peak sink capability; supports fast rise/fall times (30/15 ns). |
| CP | PSR clamp node | Provides clamping for primary-side regulation loop; connects to lower end of bias winding - critical for PSR stability. |
| CLS | Classification current programming | Resistor-to-RTN sets IEEE class signature current (e.g., 32 Ω → 39.9 mA for Class 4); enables precise PSE negotiation. |
| DEN | PoE detection signature input | 25.5-kΩ pull-up to VDD forms IEEE-mandated 25-kΩ detection impedance; pulling low disables hotswap FET. |
| RTN | PoE return / DC-DC reference ground | Common return path for PoE input and DC-DC controller analog circuitry; must be low-impedance PCB plane. |
| VDD | PoE input power rail | Accepts 37.6–60 V PoE input; includes UVLO (37.6 V typ) and internal current limiting for surge resilience. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated PSR flyback controller | Eliminates optocoupler and TL431, reducing component count by ≥4 parts and enabling compact, low-cost isolated DC-DC designs. |
| Automatic MPS with PSE-type adaptation | Adjusts pulse width and duty cycle (e.g., 26.6% for Type 1–2, 3.0% for Type 3–4) without firmware or external logic - ensures continuous power during low-load states. |
| Soft-stop shutdown | Controls GATE turn-off slew rate via I_STP resistor to minimize voltage overshoot and reduce stress on sync FET - extends FET lifetime and lowers BOM cost. |
| Programmable spread-spectrum dithering | Reduces EMI peak emissions by spreading switching energy across ~20-kHz bandwidth - relaxes input filter requirements and eases EMC certification. |
| Advanced startup with hiccup mode | Minimizes required VCC bulk capacitance (1 µF typical) while meeting IEEE 802.3bt startup timing (≤0.7 ms), and provides self-recovering fault protection. |
Applications
| VoIP Telephones | Security Cameras |
|---|---|
|
Use Scenario: Powered via single Ethernet cable in enterprise desk phone deployments with local audio processing and SIP signaling. IC Role / Device Role: PoE PD interface + isolated flyback DC-DC converter delivering regulated 3.3-V/5-V rails for codec, MCU, and Ethernet PHY. Use Value: Enables Class 3 (up to 25.5 W) operation with ±1.5% load regulation - maintains stable audio performance across varying line conditions and ambient temperatures. |
Use Scenario: Outdoor PTZ security camera requiring PoE+ power, wide temperature operation, and low standby consumption. IC Role / Device Role: IEEE 802.3at/bt PD controller with auto-MPS and PSR flyback delivering 12-V motor rail and 5-V imaging sensor rail. Use Value: Automatic MPS adaptation to Type 3 PSE reduces idle current to 19 mA (typ), extending battery backup runtime during grid outages. |
| Wireless Access Points | Redundant Power Feeds |
|
Use Scenario: Dual-band Wi-Fi 6 AP drawing up to 20 W, mounted in ceiling plenums with limited airflow. IC Role / Device Role: Primary PoE PD with thermal-aware soft-stop and 125°C junction rating - manages heat under sustained full-load operation. Use Value: 38.5°C/W θJA (VSON-45) and exposed thermal pads enable passive cooling - avoids fan requirement and acoustic noise. |
Use Scenario: Critical infrastructure switch with dual PoE inputs feeding same load via OR-ing diodes or ideal diodes. IC Role / Device Role: Dual-role PD supporting primary adapter priority input (APD) and automatic MPS coordination between feeds. Use Value: APD input disables PoE pass FET when auxiliary adapter is active - prevents backfeed and enables seamless switchover without system reset. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar PoE PD controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS23730 | Supports broader Class 1–6 range and ACF (Auxiliary Current Feed) mode; lacks APD input and T2P output. | Better suited for high-power (>30 W) lighting or digital signage where ACF improves efficiency; not compatible with APD-based adapter priority schemes. | Select TPS23730 only if Class 5/6 support or ACF is required; TPS23731 offers tighter integration for dual-input systems. |
| TPS23734 | Includes ACF support and parallel PPD (Power Present Detect) outputs; shares identical PSR architecture and pinout. | Enables higher-efficiency multi-rail designs using auxiliary current feed; requires additional external components for APD functionality. | Choose TPS23734 when ACF is needed for >30-W operation; TPS23731 remains optimal for cost-sensitive, adapter-priority Class 1–4 designs. |
Compared with TPS23730 and TPS23734, the TPS23731 uniquely combines APD-driven adapter priority, T2P PSE-type indication, and Class 1–4 optimization - making it the most integrated solution for dual-input, mid-power PoE devices requiring minimal external logic.
Availability
TPS23731 is available at Aetrix Electronics and suitable for video telephony, security camera, and wireless access point designs requiring stable component supply, long-term lifecycle assurance, and full IEEE 802.3bt compliance.
Supply support for TPS23731 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 leader specializing in analog, embedded processing, and power management ICs, with decades of leadership in Power over Ethernet technology.
The TPS23731 belongs to TI's PoE PD controller product line, engineered specifically for compact, high-efficiency IEEE 802.3bt/at-powered devices requiring integrated PSR flyback control and adaptive MPS behavior.
FAQ
What is the maximum PoE input voltage supported by the TPS23731?
The TPS23731 supports a PoE input voltage range up to 60 V on the VDD pin, with absolute maximum rating of 100 V. Its hotswap MOSFET is rated for 100 V, and the device includes undervoltage lockout (UVLO) that activates at 37.6 V (typ) on VDD rising edge - ensuring reliable operation across IEEE 802.3af/at/bt voltage envelopes while protecting against transients. The TPS23731 datasheet (SLVSER7) confirms this specification under Section 7.1 Absolute Maximum Ratings and 7.3 Recommended Operating Conditions.
Does the TPS23731 require an optocoupler for feedback in flyback designs?
No, the TPS23731 does not require an optocoupler when using primary-side regulation (PSR). Its dedicated CP and FB pins, along with PSRS enable input, support PSR architecture by sampling auxiliary winding voltage - eliminating the need for optocoupler, TL431, and associated bias network. This is explicitly documented in the TPS23731 description and Section 8.3 Feature Description. Optocoupler feedback remains optional via EA_DIS and COMP pin configuration, but PSR is the default, integrated method.
How does the TPS23731 implement automatic Maintain Power Signature (MPS)?
The TPS23731 implements automatic MPS by dynamically adjusting pulsed current amplitude and duration based on detected PSE type: for Type 1–2 PSEs, it uses ~26.6% duty cycle with 81.5-ms ON time; for Type 3–4, it switches to ~3.0% duty cycle with 7.7-ms ON time and supports auto-stretching. This behavior is fully hardware-based, requires no microcontroller intervention, and is validated in Section 7.6 Electrical Characteristics of the TPS23731 datasheet (SLVSER7).
What is the purpose of the APD pin on the TPS23731?
The APD (Auxiliary Power Detect) pin on the TPS23731 enables primary adapter priority input functionality: when pulled ≥1.5 V above RTN, it disables the internal hotswap MOSFET and turns off PoE classification, allowing seamless transition to an external DC adapter. This prevents backfeed and ensures clean power switchover - a key feature for dual-input PoE devices like enterprise phones and cameras. The APD threshold (1.5 V typ) and leakage specs are detailed in Section 7.5 of the TPS23731 datasheet.
Can the TPS23731 support synchronous rectification in flyback topology?
Yes, the TPS23731 supports synchronous rectification in flyback topology. Its PSR architecture is explicitly optimized for continuous conduction mode (CCM) with synchronous rectification, delivering improved efficiency, regulation accuracy, and step-load response. The device provides dedicated gate drive (GATE pin) and control logic for external sync FETs, and load regulation is specified as ±1.5% (typ) at 5 V output when used with sync FET - per Section 1 Features and Table 7-5 in the TPS23731 datasheet (SLVSER7).
TPS23731RMTR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 45-VFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Controller (PD), DC/DC
- Number of Channels:
- 4
- Power - Max:
- 30 W
- Internal Switch(s):
- No
- Auxiliary Sense:
- Yes
- Standards:
- 802.3at (PoE+), 802.3bt
- Voltage - Supply:
- 0V ~ 60V
- Current - Supply:
- 2mA
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 45-VQFN (7x5)
TPS23731RMTR FAQ
1.How can I place an order for TPS23731RMTR through Aetrix?
Please submit a Request for Quotation (RFQ) for TPS23731RMTR 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 TPS23731RMTR reliable?
The price and inventory of TPS23731RMTR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TPS23731RMTR is usually 5 days.
3.What payment methods are accepted for TPS23731RMTR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TPS23731RMTR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TPS23731RMTR?
TPS23731RMTR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TPS23731RMTR 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 TPS23731RMTR?
For technical support, including TPS23731RMTR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TPS23731RMTR requirements.
6.How does Aetrix verify that TPS23731RMTR is sourced from the original manufacturer or authorized distributors?
All TPS23731RMTR 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 TPS23731RMTR meets industry standards.
7.What is the process for return or replacement of TPS23731RMTR?
All TPS23731RMTR units undergo pre-shipment inspection (PSI). If there is an issue with TPS23731RMTR, 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 TPS23731RMTR part is unused and in its original packaging.
Return procedure for TPS23731RMTR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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