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Texas Instruments LM5071MT-80
- Part No.:
- LM5071MT-80
- Manufacturer:
- Texas Instruments
- Category:
- Power Over Ethernet (PoE) Controllers
- Package:
- 16-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
LM5071MT-80.pdf
- Description:
- IC POE CNTRL 1 CHANNEL 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,625
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Product details
Overview
LM5071MT-80 from Texas Instruments is a Power over Ethernet (PoE) Powered Device (PD) controller with integrated 80 V, 1 Ω, 400 mA internal MOSFET, IEEE 802.3af-compliant interface, and current-mode PWM controller for flyback/forward DC-DC conversion. It supports auxiliary AC adapter input via programmable AUX pin startup and delivers full power sequencing between PoE and auxiliary sources in VoIP phones and IP cameras.
For engineers reviewing the LM5071MT-80 datasheet, LM5071MT-80 pinout, LM5071MT-80 application, or LM5071MT-80 equivalent, key selection criteria include its 80% max duty cycle limit, slope compensation (enabled), 200 kHz typical oscillator frequency, classification current programmability, and dual-input (PoE + auxiliary) power management capability.
Technical Context
The LM5071MT-80 implements a fully integrated IEEE 802.3af PD interface with signature detection (1.8–10 V), classification (12.5–25 V), and programmable UVLO (2.00 V threshold, 10 µA hysteresis current). Its internal 80 V, 400 mA MOSFET handles inrush limiting (100 mA initial, 390 mA steady-state) and hot-swap control during PoE power-up.
The current-mode PWM controller features an error amplifier with 1.25 V reference, COMP output with 5 kΩ internal pull-up, cycle-by-cycle current limiting at 0.5 V on CS pin, and slope compensation enabled for >50% duty cycles. Oscillator frequency is set by RT resistor (200 kHz typ. at 30.3 kΩ) and supports external sync.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 1.8 V to 60 V - supports full PoE voltage range plus auxiliary adapter inputs down to 9.5 V when AUX pin is active |
| Internal MOSFET | 80 V, 1 Ω, 400 mA - enables single-chip PoE interface without external switch; handles inrush and fault current limiting |
| Oscillator Frequency | 200 kHz (typ. at RT = 30.3 kΩ) - sets switching frequency for flyback/forward converters; slope-compensated for stability |
| Duty Cycle Limit | 80% maximum - prevents subharmonic oscillation in current-mode control above 50% duty; specific to -80 suffix variant |
| Classification Current | Programmable via RCLASS pin - supports IEEE 802.3af Classes 0–4 using external resistor; internal 1.5 V reference enables precise current setting |
| UVLO Threshold | 2.00 V ±50 mV at UVLO pin - externally programmable via resistor divider; includes 10 µA hysteresis current source for clean turn-on/turn-off |
| AUX Startup Threshold | 2.5 V ±0.15 V - enables forced UVLO release below 25 V for auxiliary power sources; 350 kΩ input impedance minimizes loading |
Pinout & Package
TSSOP-16 package with exposed thermal pad (PW suffix); RoHS-compliant, 0.65 mm pitch, 5.0 mm × 4.4 mm body size.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | High-side system input | Accepts PoE or auxiliary input; diode-OR'd with other sources; rated to 80 V absolute max |
| RSIG | Signature detection node | Connects external signature resistor (target 24.5 kΩ) for PSE impedance verification during detection phase |
| RCLASS | Classification current programming | Sinks programmable current (e.g., 17–30 mA) to VEE via external resistor per IEEE 802.3af Class |
| AUX | Auxiliary power enable | 2.5 V threshold pin; forces UVLO release when auxiliary adapter is connected, enabling operation below 25 V |
| UVLO / UVLORTN | Programmable under-voltage lockout | Resistor divider from VIN to UVLORTN sets turn-on voltage; 2.00 V reference + 10 µA hysteresis current |
| VEE | System low-potential return | Common return for PoE (-) and auxiliary ground; diode-OR'd with RJ45 connector |
| RTN | PWM converter return | Drain connection of internal MOSFET; ties VEE to SMPS return path; used for soft-start release sensing |
| OUT | PWM gate driver output | 800 mA peak sink capability; drives external N-channel MOSFET gate in flyback/forward topologies |
| VCC | Internal regulator output | 7.8 V regulated supply; powers internal circuitry; shuts down when auxiliary winding raises VCC above 8.1 V |
| FB | Error amplifier inverting input | 1.25 V internal reference; connects to scaled output voltage in non-isolated designs; disables amp if tied to ARTN |
| COMP | Error amplifier output / PWM input | Open-drain output with 5 kΩ internal pull-up; interfaces directly to optocoupler in isolated designs |
| CS | Current sense comparator input | 0.5 V cycle-by-cycle trip threshold; 50 ns leading-edge blanking; requires local RC filter for noise immunity |
| RT / SYNC | Oscillator timing / sync input | Resistor-to-ARTN sets frequency; accepts narrow ac-coupled sync pulses from external clock |
| SS | Soft-start ramp control | 10 µA internal current source charges external capacitor; controls PWM ramp-up time and inrush current |
| ARTN | Analog circuit return | Separate analog ground for CS, COMP, FB, RT; reduces noise coupling into sensitive control nodes |
Key Features
| Feature | Design Value |
|---|---|
| IEEE 802.3af Compliance | Fully integrated detection, classification, and inrush control - eliminates need for discrete interface components and ensures interoperability with standard PSEs |
| Dual-Input Power Management | AUX pin enables seamless switchover between PoE and 12 V AC adapters - maintains system uptime during PoE interruption without manual intervention |
| Slope-Compensated Current Mode Control | Internal slope generator added to CS path - stabilizes control loop for duty cycles >50%, enabling higher efficiency in flyback designs |
| Integrated 80 V MOSFET with Current Limit | 1 Ω RDS(on), 400 mA rating, and programmable 390 mA DC limit - replaces external hot-swap FET and current-sense amplifier in compact PD designs |
| Thermal Shutdown Protection | 165 °C trip point with 25 °C hysteresis - prevents damage during overload or poor heatsinking; automatically recovers after cooldown |
Applications
| VoIP Phones | IP Surveillance Cameras |
|---|---|
Use Scenario: Powered via PoE infrastructure while supporting wall adapter fallback during network outages or high-power mode. IC Role / Device Role / Timing Role: LM5071MT-80 manages dual-input power handover, performs IEEE 802.3af classification (Class 3), and controls flyback converter delivering 5 V/2 A to baseband processor and codec. Use Value: Eliminates redundant power supplies and enables uninterrupted operation across PoE and auxiliary sources with automatic priority-based switchover. | Use Scenario: Outdoor PTZ camera requiring PoE+ compatibility and auxiliary 12 V input for heater/fan operation in cold environments. IC Role / Device Role / Timing Role: LM5071MT-80 executes signature detection and Class 4 classification, then regulates auxiliary input via forward converter to supply 12 V motor drivers and 3.3 V logic rails. Use Value: Enables extended functionality (e.g., pan/tilt/heating) beyond PoE power budget using same PCB footprint and control logic. |
| Wireless Access Points | Thin Clients / Set-Top Boxes |
Use Scenario: Dual-band 802.11ac AP drawing >12.95 W, requiring PoE+ negotiation and auxiliary input for peak transmit bursts. IC Role / Device Role / Timing Role: LM5071MT-80 implements Class 4 classification, controls synchronous rectified flyback delivering 12 V/1.5 A, and monitors RTN for power-good sequencing. Use Value: Supports high-power RF subsystems while maintaining IEEE compliance and avoiding costly external hot-swap controllers. | Use Scenario: Enterprise thin client powered from PoE switch but requiring auxiliary input for USB peripheral charging or display backlight boost. IC Role / Device Role / Timing Role: LM5071MT-80 provides Class 2 classification, manages auxiliary 12 V input via non-isolated buck-boost converter, and enables dynamic load sharing between sources. Use Value: Delivers flexible power architecture without redesigning power tree - auxiliary input supplements PoE during high-current USB enumeration. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar PoE PD controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM5072MT-80 | Same pinout and core functionality, but lacks auxiliary power interface (no AUX pin); no forced UVLO release below 25 V | Suitable only for pure PoE-powered devices without wall adapter support | Select LM5072MT-80 only if auxiliary input is unnecessary and board space allows removal of AUX-related resistors/dividers |
| TPS23753APW | Includes integrated 100 V, 0.6 Ω MOSFET; supports PoE+ (802.3at); no built-in slope compensation; 50% max duty cycle | Targets higher-power applications (>12.95 W); requires external slope compensation for >50% duty cycles | Choose TPS23753APW when upgrading to PoE+ or needing lower RDS(on); verify oscillator and loop compensation changes due to different duty limit |
Compared with LM5072MT-80, the LM5071MT-80 adds critical auxiliary input support; versus TPS23753APW, it trades PoE+ readiness and lower RDS(on) for integrated slope compensation and simpler design for Class 0–4 PoE with dual-source redundancy.
Availability
LM5071MT-80 is available at Aetrix Electronics and suitable for VoIP phones, IP cameras, wireless access points, and thin clients requiring stable component supply with dual-input PoE power management.
Supply support for LM5071MT-80 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 for industrial, automotive, and communications markets.
The LM5071 product line delivers integrated PoE PD controllers with auxiliary power interfaces, designed specifically for cost-sensitive, space-constrained networking endpoints requiring IEEE 802.3af compliance and seamless dual-source operation.
FAQ
What is the primary function of the LM5071MT-80 in a PoE-powered device?
The LM5071MT-80 serves as a complete IEEE 802.3af-compliant Powered Device (PD) controller with integrated power interface and current-mode PWM controller. It manages signature detection, classification, inrush limiting, and hot-swap control for PoE input while simultaneously supporting auxiliary 12 V AC adapter input via its AUX pin. The LM5071MT-80 also drives external MOSFETs in flyback or forward DC-DC converters to generate system rails, making it a single-chip solution for dual-input PoE endpoints like IP phones and cameras.
How does the LM5071MT-80 handle power source prioritization between PoE and auxiliary input?
When both PoE and auxiliary inputs are present, the LM5071MT-80 uses internal power sequencing to prioritize PoE as the primary source. The AUX pin enables forced UVLO release below 25 V, allowing the auxiliary input to power the system only when PoE is absent or insufficient. During PoE operation, the internal MOSFET remains active to charge the SMPS input capacitor, while the auxiliary path is effectively disabled unless explicitly enabled via external circuitry. This behavior is inherent to the LM5071MT-80's architecture and requires no firmware or external logic.
What distinguishes the LM5071MT-80 from the LM5071MT-50 variant?
The LM5071MT-80 includes internal slope compensation and supports up to 80% maximum duty cycle, whereas the LM5071MT-50 omits slope compensation and limits duty cycle to 50%. This makes the LM5071MT-80 suitable for flyback converters operating above 50% duty cycle-common in high-efficiency, low-input-voltage PoE designs-without requiring external compensation networks. Both variants share identical pinout, UVLO, classification, and auxiliary interface functionality, but the -80 suffix is required for stable current-mode control in demanding topologies.
Can the LM5071MT-80 be used in isolated DC-DC converter designs?
Yes, the LM5071MT-80 supports isolated topologies such as flyback and forward converters. Its COMP pin features a 5 kΩ internal pull-up resistor compatible with optocoupler-based feedback, and the FB pin can be left unconnected or tied to ARTN to disable the internal error amplifier when secondary-side regulation is used. The LM5071MT-80's current-mode control, cycle-by-cycle limiting, and soft-start remain fully functional in isolated configurations, and its 80 V MOSFET rating accommodates reflected output voltages typical in 5 V or 12 V isolated outputs.
What thermal protection mechanisms are built into the LM5071MT-80?
The LM5071MT-80 incorporates thermal shutdown protection that triggers at 165 °C junction temperature, with 25 °C hysteresis to prevent cycling near the trip point. When activated, the device disables both the internal MOSFET and PWM controller until the die cools sufficiently. This protection is independent of input voltage or load conditions and relies solely on on-die temperature sensing. The TSSOP-16 package (PW) includes an exposed thermal pad to enhance heat dissipation, and θJA is specified at 125 °C/W under standard JEDEC conditions.
LM5071MT-80 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 16-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Tube
- Product Status:
- Discontinued at Digi-Key
- 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:
- 1.8V ~ 60V
- Current - Supply:
- 1mA
- Operating Temperature:
- -40°C ~ 125°C
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-TSSOP
LM5071MT-80 FAQ
1.How can I place an order for LM5071MT-80 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM5071MT-80 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 LM5071MT-80 reliable?
The price and inventory of LM5071MT-80 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM5071MT-80 is usually 5 days.
3.What payment methods are accepted for LM5071MT-80?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM5071MT-80 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM5071MT-80?
LM5071MT-80 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM5071MT-80 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 LM5071MT-80?
For technical support, including LM5071MT-80 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM5071MT-80 requirements.
6.How does Aetrix verify that LM5071MT-80 is sourced from the original manufacturer or authorized distributors?
All LM5071MT-80 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 LM5071MT-80 meets industry standards.
7.What is the process for return or replacement of LM5071MT-80?
All LM5071MT-80 units undergo pre-shipment inspection (PSI). If there is an issue with LM5071MT-80, 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 LM5071MT-80 part is unused and in its original packaging.
Return procedure for LM5071MT-80:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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