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Texas Instruments LM5072MHX-50
- Part No.:
- LM5072MHX-50
- Manufacturer:
- Texas Instruments
- Category:
- Power Over Ethernet (PoE) Controllers
- Package:
- 16-PowerTSSOP (0.173", 4.40mm Width)
- Datasheet:
-
LM5072MHX-50.pdf
- Description:
- IC POE CNTRL 1 CHANNEL 16HTSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,510
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Product details
Overview
LM5072MHX-50 from Texas Instruments is a fully IEEE 802.3af-compliant Powered Device (PD) interface and current-mode PWM controller with integrated 100V hot-swap MOSFET (RDS(ON) = 0.7 Ω), programmable DC current limit up to 800 mA, and 50% maximum duty cycle. It enables PoE-powered devices such as IP phones, wireless access points, and network cameras requiring auxiliary power support and robust inrush control.
For engineers reviewing the LM5072MHX-50 datasheet, LM5072MHX-50 pinout, LM5072MHX-50 application, or LM5072MHX-50 equivalent, this device is selected for IEEE 802.3af PoE systems needing precise input current limiting, dual auxiliary power enable logic (front/rear), thermal shutdown protection, and flyback/forward/buck converter integration with minimal external components.
Technical Context
The LM5072MHX-50 implements peak-current-mode PWM control with inherent line feed-forward, cycle-by-cycle current limiting, and simplified loop compensation. Its dedicated 100V start-up regulator powers the internal circuitry, while the error amplifier features a 2% voltage reference and 3 MHz gain bandwidth.
It integrates IEEE 802.3af detection (24.5 kΩ signature resistor), classification (programmable via RCLASS), UVLO (38 V release / 31 V lockout), and Power Good indication (nPGOOD active-low). The -50 suffix denotes fixed 50% max duty cycle without slope compensation-distinct from the -80 variant.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Max Input Voltage | 100 V - Enables use of lower-cost transient voltage suppressors and supports PoE transients beyond IEEE 802.3af nominal range. |
| Hot Swap MOSFET RDS(ON) | 0.7 Ω - Reduces conduction loss and thermal stress during PoE startup and steady-state operation. |
| DC Current Limit Range | 150–800 mA - Programmable via external resistor on DCCL pin to match PD power class and cable loss requirements. |
| Max Duty Cycle | 50% - Fixed limit for stable operation in high-input-voltage flyback topologies; no internal slope compensation required. |
| Startup Regulator Output | 7.7 V typical at VCC - Powers gate driver and internal logic; includes 6.5 V dropout and 15 mA current limit. |
| Operating Junction Temp | –40°C to +125°C - Supports industrial and extended-temperature embedded PoE applications. |
| Thermal Shutdown | 165°C with 25°C hysteresis - Protects against sustained overload or poor PCB heat sinking in sealed enclosures. |
Pinout & Package
TSSOP-16 EP (Exposed Pad); RoHS-compliant, thermally enhanced package with 40°C/W junction-to-ambient thermal resistance. Exposed pad must be connected to VEE plane for optimal heat dissipation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 RT | Oscillator frequency programming | Resistor sets switching frequency between 50–500 kHz; determines transformer size and EMI profile. |
| 2 SS | Soft-start timing | Capacitor controls ramp rate of PWM output to prevent inrush into downstream converter. |
| 3 VIN | PoE input supply | Accepts 9–70 V PoE input; withstands up to 100 V transient; connects to hot-swap MOSFET drain. |
| 4 RCLASS | PD classification current setting | Resistor selects IEEE 802.3af Class 0–4; open = Class 0 (15.4 W PSE allocation). |
| 5 ICL_FAUX | Inrush limit & front auxiliary enable | Resistor programs 150–400 mA inrush; high logic enables front auxiliary power dominance over PoE. |
| 6 DCCL | DC current limit programming | Resistor sets 150–800 mA steady-state input current limit; critical for cable loss and thermal design. |
| 7 VEE | PoE return path | Common return for PoE and front auxiliary inputs; connects to exposed pad for thermal management. |
| 8 RTN | PWM controller ground | Drain return for hot-swap MOSFET; must tie externally to ARTN at single-point ground to minimize noise. |
| 9 OUT | PWM gate driver output | 800 mA peak sink/source drives external N-channel MOSFET; rise/fall time <20 ns with 1 nF load. |
| 10 VCC | Bias supply output | 7.7 V regulated output powers internal logic; requires local 1 µF ceramic capacitor for stability. |
| 11 nPGOOD | Power Good indicator | Active-low open-drain signal confirms hot-swap MOSFET fully on and input capacitors charged. |
| 12 CS | Current sense input | Connects to current-sense resistor; 0.5 V threshold enables cycle-by-cycle overcurrent protection. |
| 13 RAUX | Rear auxiliary power enable | Logic input selects rear auxiliary source; high = bypasses hot-swap MOSFET for direct DC-DC input. |
| 14 FB | Voltage feedback input | Inverting input of error amplifier; connects to optocoupler in isolated designs or divider in non-isolated. |
| 15 COMP | Error amplifier output | Drives PWM comparator; interfaces with secondary-side regulation via optocoupler in flyback designs. |
| 16 ARTN | Analog reference ground | Reference node for FB, COMP, CS, RT, SS; must short to RTN at single point to reduce ground bounce. |
Key Features
| Feature | Design Value |
|---|---|
| Fully integrated PD interface | Includes signature resistor (24.5 kΩ), UVLO (38 V/31 V), classification logic, and thermal shutdown - eliminates 6+ discrete components. |
| Programmable auxiliary power priority | Front auxiliary (ICL_FAUX) or rear auxiliary (RAUX) can override PoE input - enables hybrid AC/DC + PoE redundancy. |
| 100V-rated hot-swap MOSFET | 0.7 Ω RDS(ON) handles full PoE current with <1 W conduction loss at 400 mA - reduces need for heatsinking. |
| Peak-current-mode PWM control | Enables fast transient response, inherent line feed-forward, and simplified Type II compensation - ideal for flyback converters. |
| 50% max duty cycle (-50 variant) | Optimized for high-input-voltage flyback designs where duty cycle >50% risks transformer saturation and instability. |
Applications
| IP Telephony Endpoint | Wireless Access Point |
|---|---|
|
Use Scenario: Desktop VoIP phone powered exclusively via PoE, with optional AC adapter fallback. IC Role / Device Role / Timing Role: Primary PD interface and PWM controller managing 12 V/1 A isolated flyback converter; provides nPGOOD handshake to MCU. Use Value: Eliminates separate PD IC and controller; 50% duty cycle ensures stable operation across 36–57 V PoE range with minimal transformer derating. |
Use Scenario: Dual-band 802.11ac access point drawing >10 W, requiring auxiliary power during PoE brownout. IC Role / Device Role / Timing Role: Manages PoE input and seamless switchover to rear auxiliary 12 V supply using RAUX pin logic. Use Value: Maintains RF subsystem uptime during PoE interruption; programmable DCCL prevents cable overheating at 450 mA draw. |
| Network Video Camera | Industrial PoE Sensor Hub |
|
Use Scenario: Outdoor PTZ camera with heater and IR illuminator, operating in –20°C to +60°C ambient. IC Role / Device Role / Timing Role: Controls PoE input, thermal shutdown (165°C), and soft-start sequencing for multi-rail DC-DC system. Use Value: Wide –40°C to +125°C junction rating and 100 V input withstand ensure reliability in unconditioned enclosures. |
Use Scenario: DIN-rail mounted sensor aggregator powering 8x RS-485 nodes and LoRaWAN radio from PoE. IC Role / Device Role / Timing Role: Serves as central PD interface with programmable inrush (ICL_FAUX) to avoid tripping upstream PSE during cold start. Use Value: Adjustable 150–400 mA inrush prevents false PSE disconnect; TSSOP-EP package supports convection cooling in confined spaces. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Powered Device interface and PWM controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM5072MHX-80 | 80% max duty cycle with internal slope compensation; no external compensation needed for high-duty flyback. | Suitable for lower-input-voltage PoE systems (e.g., 24 V PoE) or non-isolated buck converters requiring >50% duty. | Select LM5072MHX-80 only if topology demands >50% duty cycle; LM5072MHX-50 avoids slope compensation complexity and cost. |
| LT4275AIMSE#PBF | IEEE 802.3at/af-compliant PD interface only; requires external PWM controller (e.g., LT3748) for DC-DC conversion. | Used when higher PoE power (up to 25.5 W) or multi-PD port management is required; not a single-chip solution. | Choose LT4275AIMSE#PBF when upgrading to PoE+ or when modular design mandates separation of PD and controller functions. |
Compared with LM5072MHX-80 and LT4275AIMSE#PBF, the LM5072MHX-50 delivers integrated PoE interface + PWM control in one TSSOP-16 package with deterministic 50% duty cycle-ideal for cost-sensitive, space-constrained IEEE 802.3af designs where simplicity and thermal predictability outweigh higher-power or higher-duty-cycle needs.
Availability
LM5072MHX-50 is available at Aetrix Electronics and suitable for IP telephony endpoints, wireless access points, network video cameras, and industrial sensor hubs requiring stable component supply across automotive-grade temperature ranges and long production lifecycles.
Supply support for LM5072MHX-50 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 over 50 years of power management innovation.
The LM5072 product line targets IEEE 802.3af Power over Ethernet applications, integrating PD interface and PWM control to reduce bill-of-materials and accelerate time-to-market for PoE-powered edge devices.
FAQ
What is the maximum duty cycle supported by the LM5072MHX-50?
The LM5072MHX-50 supports a fixed maximum duty cycle of 50%, as indicated by the "-50" suffix. This is implemented without internal slope compensation and is optimized for stable operation in high-input-voltage flyback converters where duty cycles above 50% risk transformer saturation. The LM5072MHX-50 datasheet specifies 47% minimum and 53% maximum duty cycle across temperature and process variation.
How does the LM5072MHX-50 handle auxiliary power sources?
The LM5072MHX-50 supports two auxiliary power configurations: front auxiliary (enabled via ICL_FAUX pin) dominates PoE input and passes through the hot-swap MOSFET, while rear auxiliary (enabled via RAUX pin) bypasses the MOSFET entirely and feeds directly to the DC-DC converter input. Both modes disable IEEE 802.3af classification, and RAUX allows seamless switchover without interrupting PWM operation.
Can the LM5072MHX-50 be used in isolated flyback designs?
Yes, the LM5072MHX-50 is explicitly designed for isolated flyback topologies. Its COMP pin interfaces with a secondary-side error amplifier via optocoupler, FB pin disables the internal error amplifier when tied to ARTN, and the 50% max duty cycle prevents core reset issues common in high-VIN flyback converters. TI Application Note SNVA222 details implementation guidelines.
What is the purpose of the exposed pad on the LM5072MHX-50 package?
The exposed metal pad on the underside of the LM5072MHX-50 TSSOP-16 EP package must be soldered to a PCB copper plane connected to the VEE pin. This provides the primary thermal conduction path, achieving 40°C/W junction-to-ambient thermal resistance. Failure to connect the pad degrades thermal performance and may trigger premature thermal shutdown under sustained 400+ mA load conditions.
How is the DC current limit programmed on the LM5072MHX-50?
The DC current limit on the LM5072MHX-50 is set using an external resistor between the DCCL pin and VEE. The relationship is IDC (mA) = (127.5 kΩ / RDCCL) - for example, a 255 kΩ resistor programs 500 mA. The datasheet guarantees ±12% accuracy across temperature, and the limit applies to steady-state PoE input current after inrush completion.
LM5072MHX-50 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 16-PowerTSSOP (0.173", 4.40mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Type:
- Controller (PD), DC/DC
- Number of Channels:
- 1
- Power - Max:
- 12.95 W
- Internal Switch(s):
- Both
- Auxiliary Sense:
- Yes
- Standards:
- 802.3af (PoE)
- Voltage - Supply:
- 9V ~ 70V
- Current - Supply:
- 2mA (Max)
- Operating Temperature:
- -40°C ~ 125°C
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-HTSSOP
LM5072MHX-50 FAQ
1.How can I place an order for LM5072MHX-50 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM5072MHX-50 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 LM5072MHX-50 reliable?
The price and inventory of LM5072MHX-50 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM5072MHX-50 is usually 5 days.
3.What payment methods are accepted for LM5072MHX-50?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM5072MHX-50 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM5072MHX-50?
LM5072MHX-50 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM5072MHX-50 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 LM5072MHX-50?
For technical support, including LM5072MHX-50 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM5072MHX-50 requirements.
6.How does Aetrix verify that LM5072MHX-50 is sourced from the original manufacturer or authorized distributors?
All LM5072MHX-50 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 LM5072MHX-50 meets industry standards.
7.What is the process for return or replacement of LM5072MHX-50?
All LM5072MHX-50 units undergo pre-shipment inspection (PSI). If there is an issue with LM5072MHX-50, 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 LM5072MHX-50 part is unused and in its original packaging.
Return procedure for LM5072MHX-50:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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