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Texas Instruments TPS23851DCE
- Part No.:
- TPS23851DCE
- Manufacturer:
- Texas Instruments
- Category:
- Power Over Ethernet (PoE) Controllers
- Package:
- 36-BSOP (0.295", 7.50mm Width)
- Datasheet:
-
TPS23851DCE.pdf
- Description:
- IC POE CNTRL 4 CHANNEL 36SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,851
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Product details
Overview
TPS23851DCE from Texas Instruments is a quad IEEE 802.3at-2009 compliant Power over Ethernet (PoE) Power Sourcing Equipment (PSE) controller in a 36-pin SSOP package. It delivers up to 30 W per port, supports four independent PSE ports, integrates 14-bit per-port A/D converters for real-time voltage and current monitoring, and implements AC/DC disconnect detection with an onboard 110-Hz oscillator - used in enterprise Ethernet switches requiring high-reliability PoE management.
For engineers reviewing the TPS23851DCE datasheet, TPS23851DCE pinout, TPS23851DCE application, or TPS23851DCE equivalent, key selection criteria include IEEE 802.3at Type 2 compliance, per-port current limit programmability (up to 720 mA), I²C watchdog for failsafe operation, and support for LLDP-based classification - all critical for scalable, fault-tolerant PoE infrastructure design.
Technical Context
The TPS23851DCE implements a four-channel PSE control architecture with independent gate drive outputs (GAT1–GAT4) for external N-channel MOSFETs, each featuring di/dt-controlled turn-on, fast short-circuit protection (<1 µs), and foldback current limiting based on real-time OUT/SEN measurements. Its integrated 110-Hz AC disconnect oscillator injects precision sine wave signals via DET pins to detect open or capacitive loads before power application.
Each port includes dedicated analog sensing paths: DETn for discovery/disconnect, SENn for current measurement (with 0.5 Ω sense resistor), and OUTn for output voltage monitoring - all digitized by independent 14-bit A/D converters. The device operates across –20°C to +125°C junction temperature and supports three operational modes: automatic, semi-automatic, and processor-controlled via I²C interface.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| IEEE Compliance | Fully compliant with IEEE Std 802.3at-2009 (Type 2), supporting up to 30 W per port |
| Port Count | Four independent PSE ports with fully isolated control and sensing circuitry |
| Current Limit Range | Programmable ICUT threshold from 45 mA to 430 mV (via 3-bit DAC); ILIM limit up to 720 mA in 2X mode |
| A/D Resolution | 14-bit per-port ADC for real-time voltage (OUTn) and current (SENn) monitoring with 15–27.5 ms conversion time |
| Operating Voltage | VDD = 3.0–3.5 V; VEE = –44 V to –57 V (nominal –48 V), enabling standard PoE midspan/splitter integration |
| Thermal Range | Specified for –20°C to +125°C junction temperature, with thermal shutdown at 143–161°C and 8°C hysteresis |
| I²C Interface | Standard-mode (100 kHz) and fast-mode (400 kHz) compatible; 4-bit address supports up to 64-port systems |
Pinout & Package
TPS23851DCE is housed in a 36-pin SSOP (DCE) package with exposed thermal pad, optimized for PoE system-level thermal management and board space efficiency.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| RESET | Digital input | Active-low reset that forces all ports off and restores registers to power-up state; includes internal 1–5 µs deglitch filter |
| INT | Open-drain output | Asserts low when interrupt register bits are set; updated between I²C transactions for host synchronization |
| SCL / SDAI / SDAO | I²C bus interface | Separate SDAI (input) and SDAO (open-drain output) enable opto-isolated I²C communication; SCL clock input supports 100–400 kHz |
| DET1–DET4 | Analog sense input | Per-port detection/disconnect sense; drives 110-Hz AC waveform during disconnect test and performs 4-point PD signature validation |
| SEN1–SEN4 | Current sense input | Single-ended inputs referenced to VEE; monitor external 0.5 Ω sense resistor for classification, foldback, and real-time current measurement |
| GAT1–GAT4 | Gate drive output | Charge-pump-driven outputs controlling external N-MOSFET gates; feature di/dt ramp control and fast short-circuit shutdown (<1 µs) |
| OUT1–OUT4 | Voltage monitor input | Monitor port output voltage via 10-kΩ resistor divider; used for power-good detection, foldback action, and A/D conversion |
| SHDN1_A / SHDN2–SHDN4 | Manual shutdown input | Active-low logic inputs for per-port or multiplexed shutdown; internally pulled up to VDD with 1–5 µs deglitch filtering |
Key Features
| Feature | Design Value |
|---|---|
| Never-Fooled 4-Point Detection | Validates PD signature using two distinct current-sink levels and voltage measurements at DET pin to reject capacitive or legacy loads |
| Onboard 110-Hz AC Disconnect Oscillator | Generates precise sine wave on DET pins to measure load impedance without external components; enables reliable AC disconnect detection |
| I²C Watchdog Timer | Prevents lockup by forcing port shutdown if I²C communication stalls, ensuring failsafe PoE operation in unattended systems |
| Per-Port 14-Bit A/D Conversion | Enables real-time, high-resolution monitoring of port voltage (OUTn) and current (SENn) for dynamic power budgeting and diagnostics |
| Flexible Operation Modes | Supports automatic (AUTO pin high), semi-automatic, and processor-controlled modes - allowing deployment with or without host MCU coordination |
| Pin Compatibility | Pin-compatible with LTC4259A and MAX5952/MAX5945/MAX5935, easing migration in multi-vendor PoE designs |
Applications
| Enterprise Ethernet Switches | VoIP Phone Power Management |
|---|---|
Use Scenario: 24- or 48-port managed switch delivering PoE++ (802.3bt) power to IP cameras, wireless APs, and IoT endpoints. IC Role / Device Role / Timing Role: Quad-channel PSE controller managing power allocation, fault detection, and thermal safety across four port groups. Use Value: Enables deterministic 30-W-per-port delivery with real-time current/voltage telemetry and automatic AC/DC disconnect - reducing field failures and service calls. |
Use Scenario: Midspan PoE injector powering multiple VoIP desk phones with remote reboot, firmware update, and power cycling capability. IC Role / Device Role / Timing Role: Centralized PSE controller executing IEEE-compliant detection, classification, and power ramping per phone port. Use Value: Supports Class 4 (30 W) power delivery with 4-point detection to avoid false positives on legacy analog phones, improving interoperability. |
| Industrial Network Routers | Smart Building Controllers |
Use Scenario: Ruggedized DIN-rail router powering PoE-enabled sensors, actuators, and edge gateways in factory automation networks. IC Role / Device Role / Timing Role: High-temperature-rated PSE controller providing robust port supervision under –20°C to +125°C conditions. Use Value: Delivers extended thermal operation and per-port A/D telemetry for predictive maintenance and energy usage analytics in harsh environments. |
Use Scenario: Building management system (BMS) controller supplying PoE to occupancy sensors, thermostats, and digital signage displays. IC Role / Device Role / Timing Role: Multi-port PSE managing power budgets across heterogeneous devices using I²C-based dynamic load profiling. Use Value: Enables LLDP-based classification and real-time current monitoring to enforce power policies and prevent overloads in shared infrastructure. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar quad-port PoE PSE controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC4259A | IEEE 802.3af-only (15.4 W/port); no 802.3at support; lacks onboard 110-Hz oscillator and 14-bit A/D converters | Suitable only for legacy PoE (Class 0–3) deployments; no high-power or advanced telemetry capability | Select when cost-sensitive 802.3af compliance is sufficient and thermal range (–40°C to +85°C) meets requirements |
| MAX5945 | Quad-port 802.3at-compliant PSE; no integrated AC disconnect oscillator; uses external timing components for disconnect detection | Requires additional external circuitry for AC disconnect; lower integration reduces BOM count but increases layout complexity | Choose when design prioritizes vendor diversification and external component reuse over single-chip simplicity |
Compared with LTC4259A and MAX5945, the TPS23851DCE provides full 802.3at Type 2 compliance, integrated AC disconnect generation, and per-port 14-bit telemetry - making it optimal for new PoE++ infrastructure where reliability, diagnostics, and thermal resilience are mandatory.
Availability
TPS23851DCE is available at Aetrix Electronics and suitable for enterprise Ethernet switches, VoIP infrastructure, industrial routers, and smart building controllers requiring stable component supply and long-term lifecycle support.
Supply support for TPS23851DCE 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 connectivity technologies with broad industrial and communications portfolio coverage.
The TPS23851DCE belongs to TI's Power over Ethernet PSE controller product line, engineered specifically for high-density, high-reliability IEEE 802.3at-compliant infrastructure equipment operating across extended temperature ranges.
FAQ
What is the maximum per-port power delivery capability of the TPS23851DCE?
The TPS23851DCE supports IEEE 802.3at Type 2 operation, delivering up to 30 W per port. This is achieved through programmable current limits (up to 720 mA in 2X mode), foldback protection, and real-time voltage/current monitoring - enabling safe, compliant power delivery to Class 4 powered devices. The TPS23851DCE does not support 802.3bt (PoE++) higher-power classes.
Does the TPS23851DCE support both AC and DC disconnect detection?
Yes, the TPS23851DCE supports both AC and DC disconnect detection. Its onboard 110-Hz oscillator generates a precision sine wave injected via DET pins for AC disconnect, while DC disconnect uses a 2.5-mV threshold on SEN pins with internal 2-µs analog filtering. Both functions operate independently per port and trigger automatic port shutdown upon detection.
How does the 4-point detection mechanism in the TPS23851DCE improve reliability?
The TPS23851DCE's 4-point detection sinks two distinct current levels into the PD signature and measures resulting DET pin voltage twice - rejecting capacitive loads, legacy devices, and miswired cables that mimic valid PD resistance. This eliminates false power application, preventing damage and ensuring only IEEE-compliant devices receive power - a core reliability feature confirmed in TI's SLUSAB3B datasheet.
Can the TPS23851DCE operate without a host microcontroller?
Yes, the TPS23851DCE supports autonomous operation via its AUTO pin. When asserted high at power-on reset, it enters auto mode and executes full detection-classification-power-on sequences independently - eliminating dependency on external firmware. Manual and semi-automatic modes remain available via I²C or SHDN pins for coordinated system control.
What package type and thermal performance does the TPS23851DCE use?
The TPS23851DCE is packaged in a 36-pin SSOP (DCE) with exposed thermal pad. It features a junction-to-ambient thermal resistance (θJA) of 52.4°C/W and operates from –20°C to +125°C junction temperature, with thermal shutdown activating at 143–161°C and 8°C hysteresis - validated per JEDEC-standard simulation on high-K PCBs as specified in TI's SLUSAB3B datasheet.
TPS23851DCE Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 36-BSOP (0.295", 7.50mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Type:
- Controller (PSE)
- Number of Channels:
- 4
- Power - Max:
- 34.2 W
- Internal Switch(s):
- No
- Auxiliary Sense:
- No
- Standards:
- 802.3at (PoE+), 802.3af (PoE)
- Voltage - Supply:
- 44V ~ 57V
- Current - Supply:
- 2mA
- Operating Temperature:
- -20°C ~ 85°C
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 36-SSOP
TPS23851DCE FAQ
1.How can I place an order for TPS23851DCE through Aetrix?
Please submit a Request for Quotation (RFQ) for TPS23851DCE 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 TPS23851DCE reliable?
The price and inventory of TPS23851DCE are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TPS23851DCE is usually 5 days.
3.What payment methods are accepted for TPS23851DCE?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TPS23851DCE transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TPS23851DCE?
TPS23851DCE orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TPS23851DCE 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 TPS23851DCE?
For technical support, including TPS23851DCE datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TPS23851DCE requirements.
6.How does Aetrix verify that TPS23851DCE is sourced from the original manufacturer or authorized distributors?
All TPS23851DCE 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 TPS23851DCE meets industry standards.
7.What is the process for return or replacement of TPS23851DCE?
All TPS23851DCE units undergo pre-shipment inspection (PSI). If there is an issue with TPS23851DCE, 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 TPS23851DCE part is unused and in its original packaging.
Return procedure for TPS23851DCE:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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