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Texas Instruments LM5073MHX
- Part No.:
- LM5073MHX
- Manufacturer:
- Texas Instruments
- Category:
- Power Over Ethernet (PoE) Controllers
- Package:
- 14-PowerTSSOP (0.173", 4.40mm Width)
- Datasheet:
-
LM5073MHX.pdf
- Description:
- IC POE CNTRL 1 CHANNEL 14HTSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,984
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Product details
Overview
LM5073MHX from Texas Instruments is a 100V IEEE 802.3af-compliant Powered Device (PD) interface IC with integrated hot-swap MOSFET (0.7Ω RDS(ON)), programmable DC current limit (up to 800 mA), auxiliary power support (front/rear), and PoE classification capability. It serves as the front-end power controller for PoE-powered devices such as IP phones, wireless access points, and network cameras.
For engineers reviewing the LM5073MHX datasheet, LM5073MHX pinout, LM5073MHX application, or LM5073MHX equivalent, key selection considerations include its 100V input rating, dual auxiliary power enable logic (FAUX/RAUX), UVLO programmability, thermal shutdown (165°C), and complementary open-drain control outputs (nSD/SD) for external DC-DC converter coordination.
Technical Context
The LM5073MHX implements a fully autonomous IEEE 802.3af PD interface with detection (24.5 kΩ signature resistance), classification (programmable via RCLASS), inrush current limiting (150 mA), and DC current limiting (440 mA default, up to 800 mA). Its integrated 100V, 0.7Ω hot-swap MOSFET enables robust surge handling and simplifies transient protection design.
It supports three power sources: PoE (VIN–VEE), front auxiliary (FAUX-enabled, ≥13V), and rear auxiliary (RAUX-enabled, ≥9V), with dominant/non-dominant arbitration. Control outputs (nSD/SD) are synchronized to nPGOOD status-asserted only when VDS of the internal MOSFET falls below 1.5V-ensuring safe DC-DC startup after capacitor charging.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 9V to 70V operating; 100V absolute max - enables use with standard PoE cabling and high-voltage transients without external clamping overhead. |
| Hot-Swap MOSFET RDS(ON) | 0.7Ω typical - reduces conduction loss and thermal stress during sustained 440–800 mA DC operation. |
| DC Current Limit | Programmable 150–800 mA via DCCL pin - supports Class 0–4 PDs and higher-power applications beyond IEEE 802.3af baseline. |
| UVLO Threshold | Default 38.5V (rise)/31V (fall); programmable - ensures reliable startup after cable drop and graceful shutdown before brownout. |
| Classification Support | IEEE 802.3af Classes 0–4 via single RCLASS resistor - allows PSE to allocate appropriate power budget per device. |
| Thermal Shutdown | 165°C with 20°C hysteresis - protects against sustained overload or poor PCB heatsinking in enclosed environments. |
| Auxiliary Power Enable | FAUX ≥8.7V (front, ≥13V min); RAUX thresholds at 2.7V/6.2V (rear, ≥9V min) - enables seamless fallback to AC adapter or solar input without firmware intervention. |
Pinout & Package
LM5073MHX is housed in a thermally enhanced 14-pin HTSSOP-EP (Exposed Pad) package. The exposed pad must be soldered to a VEE-connected PCB copper plane for effective heat dissipation (θJA = 40°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 UVLORTN | UVLO resistor divider return | Reference node for external UVLO programming; connects to VEE to set custom under-voltage trip points. |
| 2 UVLO | UVLO programming input | Selects default (tied to VIN) or programmable UVLO; also functions as remote enable/disable control. |
| 3 VIN | PoE/auxiliary positive supply input | Main high-side power rail; accepts PoE, front aux, or rear aux voltage (up to 100V absolute max). |
| 4 RCLASS | Classification current programming | Sets IEEE 802.3af power class (0–4) via external resistor to VEE; open = Class 0 (15.4W PSE allocation). |
| 5 FAUX | Front auxiliary power enable | Enables front-side auxiliary source (e.g., AC adapter) when ≥8.7V; dominant over PoE if both present. |
| 6 DCCL | DC current limit programming | Resistor-to-VEE sets 150–800 mA limit; open = 440 mA default. |
| 7 VEE | Negative supply / PoE return | Common return for PoE input, front aux, and internal circuitry; connects to current-steering bridge output. |
| 9 RTN | DC-DC converter return | Drain return path for internal hot-swap MOSFET; connects to DC-DC converter input ground. |
| 11 nPGOOD | Open-drain power-good flag | Active-low when VDS < 1.5V - signals full capacitor charge and enables downstream DC-DC startup via SD/nSD. |
| 12 nSD | Active-low DC-DC shutdown | High-impedance when nPGOOD > 2.5V; pulls low to disable DC-DC when power is unstable or absent. |
| 13 SD | Active-high DC-DC shutdown | Drives low when nPGOOD > 2.5V; complements nSD for flexible controller interface (e.g., enable vs. inhibit). |
| 14 RAUX | Rear auxiliary power enable | Dual-threshold input (2.7V/6.2V) to select rear aux dominance mode; enables battery/solar input behind DC-DC stage. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated PD signature resistor | 24.5 kΩ ±5% - eliminates external component count and ensures IEEE 802.3af detection compliance without calibration. |
| Programmable UVLO with hysteresis | Configurable 300 µs filter and independent rise/fall thresholds - prevents false triggering during PoE cable transients or load steps. |
| Complementary nSD/SD outputs | Match common DC-DC controller enable/inhibit logic - avoids level-shifting or external inverters in buck, flyback, or forward designs. |
| Front/rear auxiliary arbitration | Hardware-selectable dominance (FAUX > PoE; RAUX > PoE) - enables failover architectures without microcontroller intervention. |
| Power-good delay timer support | nPGOOD-to-RTN capacitor (e.g., 100 nF = 5 ms delay) - sustains DC-DC operation during brief PoE dips or source switchover events. |
Applications
| IP Phones | Wireless Access Points |
|---|---|
Use Scenario: Dual-power IP phone with PoE primary and AC adapter backup in enterprise offices. IC Role / Device Role / Timing Role: LM5073MHX manages PoE detection/classification, controls hot-swap MOSFET turn-on, and asserts nPGOOD only after input capacitors are charged to enable voice codec power-up. Use Value: Enables seamless transition between PoE and AC adapter without call drop; FAUX pin detects adapter presence and overrides PoE automatically. |
Use Scenario: High-density Wi-Fi 6 AP deployed in ceiling-mounted enclosures with limited airflow. IC Role / Device Role / Timing Role: LM5073MHX provides IEEE 802.3af Class 4 (30 mA classification) support, 800 mA DC current limit, and thermal shutdown to prevent overheating in confined spaces. Use Value: Sustains full RF output power under PoE+ conditions while protecting against ambient temperature derating via 165°C shutdown threshold. |
| Network Video Cameras | Industrial IoT Gateways |
Use Scenario: Outdoor PTZ camera powered by PoE with solar panel backup during grid outages. IC Role / Device Role / Timing Role: LM5073MHX uses RAUX pin to detect solar input and configure rear-auxiliary mode, routing power directly to DC-DC converter while bypassing hot-swap MOSFET. Use Value: Eliminates MOSFET conduction loss during solar operation, improving efficiency and reducing thermal load in unventilated housings. |
Use Scenario: DIN-rail mounted gateway aggregating sensor data, requiring PoE + battery backup for continuous uptime. IC Role / Device Role / Timing Role: LM5073MHX coordinates PoE and battery inputs using FAUX/RAUX logic, while nPGOOD delay capacitor (100 nF) bridges 10–20 ms PoE interruptions during battery switchover. Use Value: Maintains real-time data streaming without packet loss during source transitions, verified by 5 ms power-good hold-off. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Powered Device interface applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT4275IMS#PBF | 48V max input; no integrated hot-swap MOSFET; requires external FET and gate driver | Lacks 100V rating and auxiliary arbitration; suited for lower-power, space-constrained designs where external FET layout is acceptable | Choose LT4275IMS#PBF only if PoE voltage stays ≤48V and board area permits discrete MOSFET + driver implementation. |
| MAX5974AETM+ | 75V max input; integrated 0.9Ω MOSFET; no rear auxiliary (RAUX) support; fixed 400 mA current limit | Supports front aux only; lacks RAUX dual-threshold logic and programmable DC limit above 400 mA | Choose MAX5974AETM+ for cost-sensitive Class 0–3 PDs where rear auxiliary fallback is unnecessary and 800 mA headroom is not required. |
Compared with LM5073MHX, LT4275IMS#PBF demands more external components and offers lower voltage resilience, while MAX5974AETM+ sacrifices auxiliary flexibility and current scalability-making LM5073MHX the sole option supporting 100V operation, rear auxiliary dominance, and 800 mA programmable limit in a single IC.
Availability
LM5073MHX is available at Aetrix Electronics and suitable for IP phones, wireless access points, network video cameras, and industrial IoT gateways requiring stable component supply across extended product lifecycles.
Supply support for LM5073MHX 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 technologies, with decades of leadership in PoE interface innovation.
The LM5073MHX belongs to TI's Power over Ethernet (PoE) PD interface product line, engineered to simplify IEEE 802.3af/af+ system design by integrating signature, classification, hot-swap, and auxiliary power control into a single 14-pin package.
FAQ
What is the maximum input voltage rating for the LM5073MHX?
The LM5073MHX has an absolute maximum input voltage rating of 100V on the VIN pin relative to VEE. This allows robust operation in PoE applications with high-voltage transients and simplifies transient voltage suppressor selection. Its operating range is specified from 9V to 70V, ensuring compatibility with standard 48V PoE systems and auxiliary sources like 12V/24V adapters.
How does the LM5073MHX handle auxiliary power sources?
The LM5073MHX supports two auxiliary power configurations: front auxiliary (via FAUX pin, ≥13V min) and rear auxiliary (via RAUX pin, ≥9V min). FAUX enables auxiliary power upstream of the hot-swap MOSFET, making it dominant over PoE; RAUX enables auxiliary power downstream, allowing direct feeding of the DC-DC converter. Both modes disable classification and override UVLO behavior when active.
Can the LM5073MHX be used in IEEE 802.3at (PoE+) applications?
Yes-the LM5073MHX is compatible with IEEE 802.3at (PoE+) systems due to its 100V absolute maximum rating, programmable DC current limit up to 800 mA, and thermal shutdown at 165°C. While it implements the IEEE 802.3af PD interface, its extended current and voltage capabilities safely support higher-power PoE+ delivery when paired with appropriately rated external DC-DC converters and magnetics.
What is the function of the nPGOOD pin on the LM5073MHX?
The nPGOOD pin on the LM5073MHX is an open-drain output that goes low when the drain-to-source voltage (VDS) of the internal hot-swap MOSFET drops below 1.5V-indicating completion of input capacitor charging and readiness for DC-DC converter startup. It can drive a "Powered from PoE" LED or be capacitively filtered to provide a programmable delay (e.g., 100 nF = 5 ms) for transient ride-through.
Does the LM5073MHX require external components for IEEE 802.3af compliance?
The LM5073MHX integrates critical IEEE 802.3af functions-including the 24.5 kΩ signature resistor, classification current buffer, inrush current limiter, and UVLO circuit-minimizing external parts. Only three resistors (RCLASS, DCCL, and UVLO divider) and basic input/output capacitors are required for full compliance, significantly reducing BOM count and layout complexity compared to discrete PD interface solutions.
LM5073MHX Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 14-PowerTSSOP (0.173", 4.40mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Type:
- Controller (PD)
- Number of Channels:
- 1
- Power - Max:
- 12.95 W
- Internal Switch(s):
- Yes
- Auxiliary Sense:
- Yes
- Standards:
- 802.3af (PoE)
- Voltage - Supply:
- 9V ~ 70V
- Current - Supply:
- 2mA
- Operating Temperature:
- -40°C ~ 125°C
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 14-HTSSOP
LM5073MHX FAQ
1.How can I place an order for LM5073MHX through Aetrix?
Please submit a Request for Quotation (RFQ) for LM5073MHX 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 LM5073MHX reliable?
The price and inventory of LM5073MHX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM5073MHX is usually 5 days.
3.What payment methods are accepted for LM5073MHX?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM5073MHX transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM5073MHX?
LM5073MHX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM5073MHX 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 LM5073MHX?
For technical support, including LM5073MHX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM5073MHX requirements.
6.How does Aetrix verify that LM5073MHX is sourced from the original manufacturer or authorized distributors?
All LM5073MHX 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 LM5073MHX meets industry standards.
7.What is the process for return or replacement of LM5073MHX?
All LM5073MHX units undergo pre-shipment inspection (PSI). If there is an issue with LM5073MHX, 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 LM5073MHX part is unused and in its original packaging.
Return procedure for LM5073MHX:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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