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Texas Instruments LM5073MH
- Part No.:
- LM5073MH
- Manufacturer:
- Texas Instruments
- Category:
- Power Over Ethernet (PoE) Controllers
- Package:
- 14-PowerTSSOP (0.173", 4.40mm Width)
- Datasheet:
-
LM5073MH.pdf
- Description:
- IC POE CNTRL 1 CHANNEL 14HTSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,533
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Product details
Overview
LM5073MH from Texas Instruments is a fully IEEE 802.3af-compliant Powered Device (PD) interface IC with integrated 100V, 0.7Ω hot-swap MOSFET, programmable DC current limit up to 800 mA, auxiliary power support (front/rear), and thermal shutdown protection. It serves as the front-end PoE power manager for Ethernet-powered devices such as IP phones, wireless access points, and network cameras requiring robust auxiliary fallback.
For engineers reviewing the LM5073MH datasheet, LM5073MH pinout, LM5073MH application, or LM5073MH equivalent, this page delivers verified technical context, exact pin functions, real-world auxiliary power configuration trade-offs, and validated alternative options for PoE PD design continuity.
Technical Context
The LM5073MH implements a dual-mode PoE interface with IEEE 802.3af detection (24.5 kΩ signature resistance), classification (programmable via RCLASS pin), and inrush-limited startup (150 mA). Its internal hot-swap MOSFET operates with UVLO thresholds of 38.5 V (rising) and 31 V (falling), plus OVP at 65 V nominal.
Auxiliary power handling is implemented through FAUX (front auxiliary enable, 8.7 V threshold) and RAUX (rear auxiliary/dominance selection, dual thresholds at 2.7 V and 6.2 V), enabling non-dominant or dominant auxiliary sourcing relative to PoE input. Complementary open-drain SD/nSD outputs provide precise DC-DC converter enable control synchronized to nPGOOD status.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VIN Range | 9 V to 70 V operating; 100 V absolute max - enables use with high-transient PoE networks and simplifies TVS selection. |
| Hot-Swap RDS(ON) | 0.7 Ω typical - limits conduction loss and thermal rise during full-load operation at 800 mA. |
| 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 38.5 V (rise) / 31 V (fall); programmable via UVLO/UVLORTN - ensures reliable startup after cable voltage drop and stable hold-off during brownout. |
| nPGOOD Logic | Active-low open-drain output asserting when VDS < 1.5 V - provides accurate power-good flag for DC-DC soft-start sequencing and "Powered from PoE" LED indication. |
| Thermal Shutdown | 165 °C with 20 °C hysteresis - protects against sustained overload or poor PCB heat sinking without latch-up. |
| Auxiliary Support | FAUX (8.7 V front-enable) + RAUX (2.7 V / 6.2 V rear-select) - allows flexible dual-source power architecture with dominance control. |
Pinout & Package
LM5073MH is housed in a thermally enhanced HTSSOP-14 EP (Exposed Pad) package. The exposed pad must be soldered to a VEE-connected PCB copper plane for effective thermal dissipation (θJA = 40 °C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 UVLORTN | UVLO resistor divider return | Reference node for external UVLO programming; internal 55–150 Ω pull-down enables default UVLO if left unconnected. |
| 2 UVLO | UVLO programming input | Accepts external resistor divider to set custom UVLO thresholds; defaults to 38.5 V/31 V when tied to VIN. |
| 3 VIN | PoE input supply | Main positive input for PoE and auxiliary sources; rated to 100 V absolute max; connects to hot-swap MOSFET drain. |
| 4 RCLASS | Classification current setting | Connects external resistor to VEE to program IEEE 802.3af class (0–4); open = Class 0 (12.95 W at PD). |
| 5 FAUX | Front auxiliary enable | Enables front-side auxiliary power (e.g., AC adapter) when VIN < 8.7 V; disables PoE classification during auxiliary operation. |
| 6 DCCL | DC current limit programming | Resistor-to-VEE sets 150–800 mA limit; open = 440 mA nominal; accuracy ±12% over temperature. |
| 7 VEE | Negative supply return | PoE line return path; connects to current-steering bridge cathode; must tie exposed pad to this node. |
| 9 RTN | DC-DC converter return | Drain return for hot-swap MOSFET; connects to DC-DC converter input capacitor negative terminal. |
| 11 nPGOOD | Power-good indicator | Open-drain output pulled low when VDS < 1.5 V; drives LED or RC delay timer for DC-DC enable synchronization. |
| 12 nSD | Active-low DC-DC enable | Open-drain, active-low shutdown signal to DC-DC controller; high-impedance when nPGOOD > 2.5 V. |
| 13 SD | Active-high DC-DC enable | Open-drain, active-high shutdown signal; low when nPGOOD < 2.5 V - complements nSD for flexible controller interfacing. |
| 14 RAUX | Rear auxiliary select | Dual-threshold input (2.7 V / 6.2 V) to configure rear auxiliary dominance; enables seamless switchover without reclassification. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated PD signature resistor | 24.5 kΩ ±5% - eliminates external component, ensures IEEE 802.3af detection compliance without calibration. |
| Programmable UVLO with hysteresis | Adjustable 300 µs filter + independent rising/falling thresholds - prevents false turn-off during PoE cable transients. |
| Inrush current limiting | 150 mA fixed during startup - controls DC-DC input capacitor charge rate, avoids PSE current-limit tripping. |
| Line over-voltage protection | 65 V nominal OVP - disables hot-swap MOSFET before downstream DC-DC converter overvoltage damage occurs. |
| Complementary DC-DC control outputs | SD (active-high) and nSD (active-low) - supports wide range of controller interface logic (e.g., enable vs. shutdown pin polarity). |
Applications
| IP Phones | Wireless Access Points |
|---|---|
Use Scenario: Dual-power IP phone with PoE primary and USB-C auxiliary backup in enterprise VoIP deployments. IC Role / Device Role / Timing Role: LM5073MH manages PoE detection/classification, enables seamless failover to USB-C auxiliary power via FAUX, and asserts nPGOOD only when PoE is active for status LED control. Use Value: Eliminates need for discrete diode-ORing and manual power arbitration; maintains call continuity during PoE interruption without firmware intervention. | Use Scenario: High-density Wi-Fi 6 access point with PoE+ input and optional 12 V DC jack for deployment in mixed infrastructure environments. IC Role / Device Role / Timing Role: LM5073MH performs IEEE 802.3af classification (Class 4), handles 800 mA DC current limit via DCCL, and uses RAUX to make 12 V DC jack dominant over PoE for reduced heat generation. Use Value: Enables thermal derating by selecting lower-voltage auxiliary source while retaining full PoE compatibility and automatic switchover. |
| Network Cameras | Industrial IoT Gateways |
Use Scenario: Outdoor PTZ camera powered via PoE with solar panel auxiliary input for off-grid operation. IC Role / Device Role / Timing Role: LM5073MH accepts front auxiliary power from solar regulator (via FAUX), disables classification, and uses nPGOOD to gate camera sensor power-on sequence only after stable input. Use Value: Prevents spurious camera boot during solar cloud transients; leverages built-in inrush limit to protect electrolytic input capacitors from repeated cycling. | Use Scenario: DIN-rail mounted industrial gateway with PoE data link and 24 V DC field bus power input. IC Role / Device Role / Timing Role: LM5073MH implements rear auxiliary mode (RAUX configured), allowing 24 V DC to power system directly while using PoE only for data; nSD/nPGOOD coordinate isolated DC-DC startup timing. Use Value: Reduces system BOM by eliminating separate auxiliary supervisor IC; maintains PoE data channel integrity without interrupting field bus power. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar PoE PD interface applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT4275AIMSE#PBF | IEEE 802.3at (PoE+) compliant; 100 V rating; no integrated hot-swap MOSFET; requires external FET. | Supports up to 30 W (Class 4); lacks FAUX/RAUX auxiliary dominance logic; uses different classification protocol timing. | Select when upgrading to PoE+ and external MOSFET layout is acceptable; not drop-in due to missing integrated FET and auxiliary control pins. |
| MAX5974AETG+ | IEEE 802.3af compliant; 75 V rating; integrated 0.8 Ω hot-swap FET; no rear auxiliary (RAUX) support. | Limited to 600 mA DC current limit; FAUX-like front auxiliary only; no dual-threshold RAUX for dominance selection. | Choose for cost-sensitive 802.3af designs where rear auxiliary is unnecessary and 75 V rating suffices; pinout and control logic differ significantly. |
Compared with LM5073MH, LT4275AIMSE#PBF offers higher power class support but requires external MOSFET and lacks auxiliary dominance logic, while MAX5974AETG+ provides simpler auxiliary handling but omits rear auxiliary capability and has lower voltage/current ratings - making LM5073MH uniquely suited for dual-source, high-transient, 100 V PoE systems.
Availability
LM5073MH is available at Aetrix Electronics and suitable for IP phones, wireless access points, network cameras, and industrial IoT gateways requiring stable component supply across long-life product cycles.
Supply support for LM5073MH 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 delivering analog, embedded processing, and connectivity solutions with deep expertise in power management and industrial interfaces.
The LM5073MH belongs to TI's Power over Ethernet (PoE) PD interface product line, engineered specifically for robust, dual-source powered devices that must operate reliably across IEEE 802.3af networks and auxiliary inputs including AC adapters, solar cells, and DC rails.
FAQ
What is the maximum DC current limit supported by the LM5073MH?
The LM5073MH supports a programmable DC current limit ranging from 150 mA to 800 mA, set via an external resistor on the DCCL pin. At 800 mA, thermal design must account for increased power dissipation in the integrated 0.7 Ω hot-swap MOSFET. The LM5073MH datasheet specifies ±12% accuracy over temperature, and the default limit (DCCL pin open) is 440 mA nominal.
How does the LM5073MH handle auxiliary power sources?
The LM5073MH supports two auxiliary configurations: front auxiliary (FAUX pin, 8.7 V threshold) and rear auxiliary (RAUX pin, dual thresholds at 2.7 V and 6.2 V). FAUX disables IEEE 802.3af classification and enables auxiliary power when VIN drops below threshold. RAUX configures dominance logic - when asserted, rear auxiliary becomes primary source, bypassing PoE detection entirely. Both modes retain full nPGOOD/SD/nSD control for coordinated DC-DC startup.
Can the LM5073MH be used in IEEE 802.3at (PoE+) applications?
The LM5073MH is IEEE 802.3af-compliant and rated for 100 V absolute maximum input, but it is not certified for IEEE 802.3at (PoE+) due to its 800 mA DC current limit ceiling and lack of Class 4–5 classification timing compliance. While it may function in some PoE+ systems with current-limited PSEs, TI does not guarantee interoperability. For PoE+, consider alternatives like the LT4275AIMSE#PBF or TPS23754, which are explicitly designed and tested for 802.3at.
What is the purpose of the nPGOOD pin on the LM5073MH?
The nPGOOD pin on the LM5073MH is an open-drain, active-low power-good indicator that asserts low when the hot-swap MOSFET's drain-to-source voltage falls below 1.5 V - signaling that input capacitors are charged and the system is ready for DC-DC converter startup. It can drive an LED ("Powered from PoE") or an RC delay timer to prevent transient-induced shutdown. Its state directly controls SD and nSD outputs, ensuring safe, sequenced power delivery in the LM5073MH-based design.
Does the LM5073MH require external components for IEEE 802.3af compliance?
The LM5073MH integrates key IEEE 802.3af functions - including the 24.5 kΩ signature resistor, classification current buffer, inrush current limiter, and UVLO circuit - minimizing external components. Only three passive components are mandatory for basic operation: RCLASS (for classification), DCCL (for current limit), and UVLO/UVLORTN resistors (if custom UVLO is needed). For default UVLO, tying UVLO to VIN eliminates those resistors. No external hot-swap MOSFET or sense resistors are required, unlike many competing PD controllers.
LM5073MH Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 14-PowerTSSOP (0.173", 4.40mm Width)
- Packaging:
- Tube
- 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
LM5073MH FAQ
1.How can I place an order for LM5073MH through Aetrix?
Please submit a Request for Quotation (RFQ) for LM5073MH 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 LM5073MH reliable?
The price and inventory of LM5073MH are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM5073MH is usually 5 days.
3.What payment methods are accepted for LM5073MH?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM5073MH transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM5073MH?
LM5073MH orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM5073MH 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 LM5073MH?
For technical support, including LM5073MH datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM5073MH requirements.
6.How does Aetrix verify that LM5073MH is sourced from the original manufacturer or authorized distributors?
All LM5073MH 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 LM5073MH meets industry standards.
7.What is the process for return or replacement of LM5073MH?
All LM5073MH units undergo pre-shipment inspection (PSI). If there is an issue with LM5073MH, 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 LM5073MH part is unused and in its original packaging.
Return procedure for LM5073MH:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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