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Analog Devices Inc./Maxim Integrated MAX5984DETI+T
- Part No.:
- MAX5984DETI+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Power Over Ethernet (PoE) Controllers
- Package:
- 28-WFQFN Exposed Pad
- Datasheet:
-
MAX5984DETI+T.pdf
- Description:
- IC POE CNTRL 1 CHANNEL 28TQFN
- Quantity:
- Payment:
- Shipping:
Inventory:2,461
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Product details
Overview
MAX5984DETI+T from Maxim Integrated is a single-port IEEE 802.3af/at Power Sourcing Equipment (PSE) controller with integrated 0.5Ω MOSFET and sense resistor, delivering up to 40W per port. It performs automatic PD discovery, classification (including Class 5 and 2-event), DC/AC load-disconnect detection, and supports legacy high-capacitance PDs in industrial PoE injectors and midspan applications.
For engineers reviewing the MAX5984DETI+T datasheet, MAX5984DETI+T pinout, MAX5984DETI+T application, or MAX5984DETI+T equivalent, this page delivers verified specifications, real-world timing behavior (e.g., 330ms max detection time, 19–23ms classification window), thermal shutdown at +150°C, and LSCEN-enabled load stability check - all confirmed for the MAX5984DETI+T variant.
Technical Context
The MAX5984DETI+T implements fully autonomous PSE control logic without firmware, using analog voltage probing (VDPH1 = 4.0V typ, VDPH2 = 9.3V typ) and current sensing (ICLIM = 65–80mA during classification) to validate IEEE-compliant PD signatures. Its internal 9-bit ADC and triangular wave generator (AMPTRW = 4.0Vpp) enable simultaneous DC disconnect (IDCTH = 7.5mA) and AC disconnect (IACTH = 130µA) monitoring.
It integrates a thermally optimized 28-pin TQFN package with exposed pad (θJA = 29°C/W), supports programmable Class 5 current limits (850mA typ) via ILIM1/ILIM2 configuration, and features hardware-latched inputs (MIDSPAN, LEGACY, OSC) that freeze after power-up or reset - ensuring deterministic behavior in end-point and midspan topologies.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| IEEE Compliance | Fully compliant with 802.3af and 802.3at standards, including Class 0–5 detection and 2-event classification support. |
| Max Output Power | 40W per port (Class 5 enabled), achieved with integrated 0.5Ω MOSFET and internal current-sense resistor. |
| Current Limit Range | Programmable Class 5 limit: 850mA typical (ILIM1 = unconnected, ILIM2 = VEE), enabling robust high-power PD delivery. |
| Load Disconnect | DC disconnect threshold: 7.5mA; AC disconnect threshold: 130µA - ensures safe port shutdown under no-load or open-circuit conditions. |
| Thermal Protection | Overtemperature shutdown at +150°C with 20°C hysteresis, preventing latch-up during sustained overload or ambient stress. |
| Operating Voltage | 32V to 60V input range (VAGND – VEE), supporting standard PoE midspan and end-point supply rails. |
| Detection Timing | Max 330ms detection time, 19–23ms classification window, and 2.2s midspan retry delay - meets IEEE timing requirements. |
Pinout & Package
MAX5984DETI+T uses a 28-pin TQFN-EP (5mm × 5mm) package with exposed pad connected to VEE. Pin functions are validated per Maxim's official pin description table and schematic guidelines.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1,2,3,8–11,15 | VEE | Analog low-side supply input; all tied together and bypassed externally to AGND with 47µF + 0.1µF capacitors. |
| 4,5 | ILIM1 / ILIM2 | Digital inputs configuring Class 5 current limit; MAX5984DETI+T uses LSCEN on pin 6, so ILIM1/ILIM2 set Class 5 thresholds per Table 3. |
| 6 | LSCEN | Load Stability Check Enable - unconnected enables function; forced low disables it (pin-specific to MAX5984D variant). |
| 7 | MIDSPAN | Midspan collision avoidance control; latched at power-up - high enables cadence timing (2.2s retry delay). |
| 12 | VEE_DIG | Digital low-side supply; externally connected to VEE to unify analog/digital ground reference. |
| 13 | LEGACY | Legacy PD detection enable; latched at reset - unconnected enables high-capacitance detection (up to 47µF). |
| 14 | EN | Hardware reset input; driven low >40µs forces full state reset and re-latches MIDSPAN/LEGACY/OSC. |
| 17 | LED | Open-drain LED driver output; sinks up to 10mA with PWM blinking for status indication (e.g., powered, fault, class). |
| 19 | OSC | AC disconnect triangular wave output; requires 100nF capacitor to VEE to activate AC disconnect mode. |
| 21 | AGND | High-side supply input; referenced to VEE and used as return path for detection circuitry and external biasing. |
| 23 | DET | Detection/classification voltage node; sources probe voltages (4.0V/9.3V) and senses PD current during classification. |
| 25 | OUTP | Port pullup output; connects to AC-blocking diode anode when AC disconnect is active, or directly to OUT otherwise. |
| 26,27 | OUT | Integrated MOSFET drain output; delivers regulated PSE power to PD; connects to cathode of AC-blocking diode in AC mode. |
| 16,18,20,22,24,28 | N.C. | No-connect pins - not internally bonded; must remain unconnected per layout guidelines. |
| EP | Exposed Pad | Thermal and electrical connection to VEE; required for thermal performance (θJC = 2°C/W) and EMI reduction. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated Power MOSFET | 0.5Ω RDS(ON) at +25°C (0.9Ω max), eliminating external FET and reducing BOM count and board space. |
| Class 5 Classification Support | Enables up to 40W delivery via configurable ILIM1/ILIM2 pins - verified for MAX5984DETI+T in Table 3 of datasheet. |
| Load Stability Check (LSCEN) | Pin 6 function unique to MAX5984D variants; detects unstable loads before full power application, preventing false disconnects. |
| DC & AC Load-Disconnect Detection | Simultaneous monitoring: DC threshold = 7.5mA, AC threshold = 130µA - ensures reliable port shutdown under all fault conditions. |
| High-Capacitance Legacy Detection | Supports PD signature capacitances up to 47µF (typ) when LEGACY pin is unconnected - maintains compatibility with older PoE devices. |
| Thermal & Electrical Protection | Includes VEE UVLO (28.5V), OVL (62.5V), overtemperature shutdown (+150°C), and foldback current limiting (VFLBK_ST = 27V). |
Applications
| Industrial PoE Injectors | Wireless Access Points |
|---|---|
Use Scenario: Midspan PoE injector powering IP cameras and sensors in factory automation networks with long cable runs and variable ambient temperature. IC Role / Device Role / Timing Role: Single-port PSE controller performing IEEE-compliant detection, Class 4/5 classification, and dual-mode (DC/AC) load disconnect to maintain uptime. Use Value: Integrated MOSFET and LSCEN reduce component count and prevent nuisance tripping due to motor startup or EMI-induced current transients. |
Use Scenario: Compact 802.11ac/ax access point requiring 30W+ power over Cat5e/6 cabling in enterprise office environments. IC Role / Device Role / Timing Role: End-point PSE managing port power-up sequence, 2-event classification for high-power clients, and thermal-safe 40W delivery. Use Value: 330ms detection window and 23ms classification ensure rapid client association while maintaining IEEE timing compliance. |
| PoE Repeaters | Smart Building Controllers |
Use Scenario: In-building PoE repeater extending power and data to remote lighting nodes and occupancy sensors beyond 100m Ethernet reach. IC Role / Device Role / Timing Role: Autonomous PSE controller executing repeated detection cycles (2.2s midspan delay) and sustaining stable 40W output under varying load capacitance. Use Value: High-capacitance detection (47µF) and legacy mode support ensure interoperability with diverse endpoint devices across generations. |
Use Scenario: DIN-rail mounted HVAC controller receiving power and Modbus/TCP data over single Ethernet cable in commercial HVAC systems. IC Role / Device Role / Timing Role: Robust PSE interface handling frequent load connect/disconnect events and operating continuously at +70°C ambient. Use Value: Thermal shutdown (+150°C) with 20°C hysteresis and 29°C/W θJA enable reliable operation in enclosed enclosures without forced air cooling. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar PSE controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX5982AETI+ | Single-port, 30W (Class 4), no Class 5 or LSCEN support; uses separate external MOSFET. | Suitable for cost-sensitive 802.3af-only deployments where 40W is unnecessary. | Select MAX5982AETI+ only if Class 5 and integrated FET are not required - avoids overdesign and reduces cost. |
| LT4275AIMSE#PBF | Single-port, 30W, supports 802.3at but lacks native Class 5; requires external MOSFET and sense resistor. | Better suited for designs needing I²C configurability and flexible fault reporting, not autonomous operation. | Choose LT4275AIMSE#PBF when system-level microcontroller coordination is available and thermal design allows discrete FET placement. |
Compared with MAX5982AETI+ and LT4275AIMSE#PBF, the MAX5984DETI+T uniquely combines 40W Class 5 capability, integrated MOSFET, and LSCEN functionality in a single 28-pin TQFN - eliminating external components and enabling faster, more robust PoE deployment without firmware.
Availability
MAX5984DETI+T is available at Aetrix Electronics and suitable for industrial PoE injectors, wireless access points, PoE repeaters, and smart building controllers requiring stable component supply and guaranteed long-term availability.
Supply support for MAX5984DETI+T 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
Maxim Integrated (now part of Analog Devices) is a semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for industrial, communications, and computing applications.
The MAX5984 product line delivers fully autonomous, single-port IEEE 802.3af/at PSE controllers targeting space-constrained, high-reliability PoE infrastructure - designed specifically for midspan injectors, end-point switches, and embedded network equipment.
FAQ
What is the function of the LSCEN pin on the MAX5984DETI+T?
The LSCEN (Load Stability Check Enable) pin is specific to the MAX5984D variant and controls whether the device performs pre-power stability verification on connected PDs. When unconnected, LSCEN enables the function - detecting transient load instability before full power application. This prevents false disconnects caused by inrush or capacitive loads. The MAX5984DETI+T datasheet confirms LSCEN is active by default and configurable only at reset. MAX5984DETI+T relies on this feature for robust operation in industrial environments with motor-driven or LED-based PDs.
Does the MAX5984DETI+T support IEEE 802.3bt (PoE++)?
No, the MAX5984DETI+T does not support IEEE 802.3bt. It is explicitly designed for 802.3af (up to 15.4W) and 802.3at (up to 30W) compliance, with extended Class 5 operation delivering up to 40W using proprietary enhancements within the 802.3at framework. The datasheet makes no reference to 802.3bt features such as autoclass, multi-event classification, or 4-pair power delivery. For 802.3bt designs, engineers must select newer controllers like the MAX5986 or Analog Devices' LTC4269 series. MAX5984DETI+T remains optimal for cost-effective, single-port 40W-at-class deployments.
How does the MAX5984DETI+T handle legacy PDs with high signature capacitance?
The MAX5984DETI+T supports legacy PDs with signature capacitances up to 47µF (typical) when the LEGACY pin is left unconnected - its internal pull-up activates high-capacitance detection mode. This ensures compatibility with older VoIP phones and early IP cameras that exceed the 150nF limit defined in 802.3af. The device validates both resistance (19–26.5kΩ) and capacitance windows per Table 1, rejecting invalid signatures below 15kΩ or above 32kΩ. MAX5984DETI+T's dual-phase detection (VDPH1 = 4.0V, VDPH2 = 9.3V) and slope measurement algorithm guarantee accurate identification even with elevated parasitic capacitance.
What is the thermal performance of the MAX5984DETI+T in continuous 40W operation?
In continuous 40W operation at +70°C ambient, the MAX5984DETI+T achieves junction temperatures below +130°C on a standard 4-layer JEDEC PCB (θJA = 29°C/W), well within its +150°C shutdown threshold. Its exposed pad (EP) must be soldered to a VEE-connected copper plane for effective heat dissipation - θJC is only 2°C/W. Derating begins above +70°C at 34.5mW/°C, allowing ~2.8W additional dissipation margin before thermal shutdown. MAX5984DETI+T's foldback current limiting (VFLBK_ST = 27V) further protects against thermal runaway during overload. Layout adherence to Maxim's thermal guidelines is essential for sustained 40W delivery.
Can the MAX5984DETI+T be used in both end-point and midspan PSE topologies?
Yes, the MAX5984DETI+T supports both end-point and midspan topologies via the MIDSPAN pin. When MIDSPAN is unconnected (internally pulled high), the device enters midspan mode - implementing 2.2s cadence timing between failed detection attempts. When MIDSPAN is forced low, it operates in end-point mode with immediate retry. The pin state is latched at power-up or reset, ensuring topology persistence. This dual-mode capability, combined with independent LEGACY and OSC configuration, makes MAX5984DETI+T suitable for universal PoE hardware platforms - reducing SKU count and simplifying inventory for switch manufacturers and injector OEMs.
MAX5984DETI+T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 28-WFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Type:
- Controller (PSE)
- Number of Channels:
- 1
- Power - Max:
- 40 W
- Internal Switch(s):
- Yes
- Auxiliary Sense:
- No
- Standards:
- 802.3at (PoE+), 802.3af (PoE)
- Voltage - Supply:
- 32V ~ 60V
- Current - Supply:
- 2.5mA
- Operating Temperature:
- -40°C ~ 85°C
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-TQFN (5x5)
MAX5984DETI+T FAQ
1.How can I place an order for MAX5984DETI+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX5984DETI+T 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 MAX5984DETI+T reliable?
The price and inventory of MAX5984DETI+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX5984DETI+T is usually 5 days.
3.What payment methods are accepted for MAX5984DETI+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX5984DETI+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX5984DETI+T?
MAX5984DETI+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX5984DETI+T 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 MAX5984DETI+T?
For technical support, including MAX5984DETI+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX5984DETI+T requirements.
6.How does Aetrix verify that MAX5984DETI+T is sourced from the original manufacturer or authorized distributors?
All MAX5984DETI+T 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 MAX5984DETI+T meets industry standards.
7.What is the process for return or replacement of MAX5984DETI+T?
All MAX5984DETI+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX5984DETI+T, 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 MAX5984DETI+T part is unused and in its original packaging.
Return procedure for MAX5984DETI+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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