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Microchip Technology PD77728ILQ-0111-TR
- Part No.:
- PD77728ILQ-0111-TR
- Manufacturer:
- Microchip Technology
- Category:
- Power Over Ethernet (PoE) Controllers
- Package:
- 56-VFQFN Exposed Pad
- Datasheet:
-
PD77728ILQ-0111-TR.pdf
- Description:
- 8 PORT IEEE 802.3 BT TYPE 4, FUL
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
PD77728ILQ-0111-TR from Microchip Technology is an IEEE 802.3bt-compliant 8-port Power over Ethernet (PoE) Power Sourcing Equipment (PSE) manager with integrated FET switches, current sense resistors, and real-time protection circuitry. It delivers up to 90W per 4-pair port at VMAIN = 52V, supports semi-auto/managed/unmanaged auto operation modes, and operates across –40 °C to +85 °C ambient for enterprise switch and PoE injector applications.
For engineers reviewing the PD77728ILQ-0111-TR datasheet, PD77728ILQ-0111-TR pinout, PD77728ILQ-0111-TR application, or PD77728ILQ-0111-TR equivalent, key selection criteria include guaranteed 4-pair output power >90W, total channel resistance ≤160 mΩ, IEC61000-4-5 surge immunity up to 2 kV without external components, per-port RTP with <100 µs short-circuit disconnect, and Fast-Mode Plus I²C host interface compatibility.
Technical Context
The PD77728ILQ-0111-TR integrates a Cortex-M0+ based PoE controller with eight independent analog front-end blocks-each containing detection, classification, MarkHold, ILIM/TLIM control, and SCP circuitry. Its digital processing block manages port sequencing, power budgeting, and firmware-upgradable IEEE 802.3bt compliance logic including AutoClass, Fast PoE, and Perpetual PoE support.
Real-time protection is implemented in the digital domain with per-port configurable thresholds for TLIM (7–11 ms), ICUT (0.375–1.090 A), and OVT activation at 150 °C junction temperature. The device supports dual power rails (55V and 3.3V), achieves ≤2 W total power dissipation at full 4-pair Class 8 load, and enables cascading up to 12 devices for 48 × 4-pair ports.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| IEEE Standard | Compliant with IEEE 802.3bt (Type 4), backward-compatible with 802.3af/at and legacy PDs. |
| Port Count & Configuration | 8-port standalone; supports 2-pair or 4-pair per port, any mix, up to 4 × 4-pair or 8 × 2-pair simultaneously. |
| Max Output Power | Guaranteed >90W per 4-pair port at VMAIN = 52V; supports up to 100W under test conditions. |
| Total Channel Resistance | 160 mΩ typical at 25 °C - minimizes conduction loss and thermal stress during high-current operation. |
| Surge Immunity | 2 kV common-mode per IEC61000-4-5-2014 without external protection components. |
| Short-Circuit Disconnect | <100 µs typical response - protects MOSFET SOA during harsh fault events. |
| Operating Temperature | –40 °C to +85 °C ambient - validated for industrial-grade switch and lighting infrastructure deployment. |
Pinout & Package
PD77728ILQ-0111-TR is housed in a 56-pin 8 mm × 8 mm QFN package with exposed thermal pad (MSL3, RoHS compliant). Pin assignments are validated per Microchip DS00003920F, Table 3-1.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| PORT_NEG0–PORT_NEG7 (Pins 3,5,10,12,31,33,38,40) | Negative output for PoE port 0–7 | Direct connection to negative side of PoE transformer; each drives up to 1.2 A continuous (Class 8). |
| VMAIN (Pin 17) | Main PoE supply input | Accepts 44–57 V DC; requires local 1 µF/100V X7R capacitor; powers internal FETs and analog blocks. |
| IREF (Pin 14) | External current reference input | Connects to 10 kΩ ±0.1% resistor to AGND; sets precision for port current measurement and classification. |
| INT_OUT_N (Pin 45) | Open-drain interrupt output | Asserts low on port fault, classification completion, or RTP event; supports daisy-chained interrupt handling. |
| RESET_IN_N (Pin 44) | Active-low reset input | Asynchronous hardware reset; requires external pull-up to VDD; initiates full device initialization sequence. |
| VDD / VDDA (Pins 43, 22) | Digital and analog 3.3V supplies | Separate 3.3V domains decoupled to DGND/AGND; enable low-noise analog sensing and robust digital control. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated FET + Sense Resistor | Per-port 160 mΩ RCH_ON and on-chip current sense eliminate external discrete components and layout complexity. |
| Real-Time Protection (RTP) | Eight independent, firmware-configurable protection blocks per port - SCP, TLIM, ICUT, OVT, MPS - all act within microseconds. |
| Cascadable Architecture | Up to 12 devices synchronized via I²C enable scalable 48-port 4-pair PSE systems without custom interconnect logic. |
| Firmware-Upgradeable Controller | Pre-programmed Cortex-M0+ core supports field updates via I²C; enables future IEEE standard extensions and bug fixes. |
| MarkHold Function Support | Analog MarkHold input (Pin 15) allows external control of signature maintenance timing for non-standard PDs. |
Applications
| Enterprise Campus Switches | Smart Lighting Controllers |
|---|---|
|
Use Scenario: High-density Layer 2/3 switches powering VoIP phones, wireless APs, and security cameras across multi-floor buildings. IC Role / Device Role / Timing Role: Centralized 8-port PSE manager performing IEEE 802.3bt detection, classification, power delivery, and real-time fault management per port. Use Value: Enables single-board 8-port 90W+ PoE capability with <100 µs SCP response, eliminating need for external protection ICs and reducing BOM count by ≥12 components per port. |
Use Scenario: Outdoor LED streetlight controllers delivering both power and data over single Cat5e cable to distributed luminaires. IC Role / Device Role / Timing Role: Robust 4-pair PoE PSE managing up to 100W per light node while surviving outdoor surge environments (IEC61000-4-5 2 kV). Use Value: Guarantees >90W per port at 52V with built-in surge tolerance - removes requirement for external TVS arrays and simplifies IP66-rated enclosure design. |
| PoE Injectors (Midspan) | SMB/SoHo Network Routers |
|
Use Scenario: Compact 1–4 port midspan injectors adding PoE capability to legacy non-PoE switches in small offices or retail locations. IC Role / Device Role / Timing Role: Standalone 8-port PSE operating in Unmanaged Auto mode - fully autonomous detection, power-up, and maintenance without host MCU intervention. Use Value: Supports plug-and-play deployment with zero firmware integration; leverages integrated MarkHold and AutoClass to power diverse legacy and modern PDs. |
Use Scenario: Integrated PoE routing platforms for home automation hubs, mesh Wi-Fi systems, and IoT gateways requiring reliable low-power PoE delivery. IC Role / Device Role / Timing Role: Low-power 2-pair PSE manager delivering up to 30W per port with <2 W total dissipation and –40 °C to +85 °C operation. Use Value: Achieves full IEEE 802.3bt compliance in thermally constrained consumer enclosures using only internal thermal shutdown and OVT protection. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar PoE PSE manager applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| PD77724ILQ-0111-TR | 4-port variant with identical architecture, firmware, and 90W/port capability; shares same pinout footprint but fewer PORT_NEG pins. | Suitable for cost-sensitive or space-constrained 4-port injectors or edge switches where full 8-port density is unnecessary. | Select when system requires ≤4 PoE ports and board area or BOM cost optimization is prioritized over scalability. |
| PD77732ILQ-0111-TR | 12-port version with extended cascade support (up to 16 devices); higher VMAIN UVLO threshold (31.5 V) and enhanced thermal derating above 70 °C. | Targeted at carrier-grade aggregation switches and large-scale smart building deployments requiring >48 ports. | Choose for high-port-count systems needing native 12-port integration and extended thermal margin in enclosed chassis. |
Compared with PD77724ILQ-0111-TR and PD77732ILQ-0111-TR, the PD77728ILQ-0111-TR provides optimal balance of port count, thermal efficiency (≤2 W), and cascade flexibility (up to 12 devices) - making it the preferred choice for mid-tier enterprise switches and modular PoE injectors requiring 8 dedicated ports without over-engineering.
Availability
PD77728ILQ-0111-TR is available at Aetrix Electronics and suitable for enterprise campus switches, smart lighting controllers, and PoE injectors requiring stable component supply, long-term lifecycle assurance, and full IEEE 802.3bt compliance.
Supply support for PD77728ILQ-0111-TR 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
Microchip Technology Inc. is a global semiconductor company specializing in microcontrollers, analog devices, and connectivity solutions, with leadership in embedded control and power management ICs.
The PD77728ILQ-0111-TR belongs to Microchip's seventh-generation IEEE 802.3bt PoE PSE family, engineered for high-efficiency, scalable, and standards-compliant Power over Ethernet infrastructure in enterprise, industrial, and smart-building applications.
FAQ
What is the maximum guaranteed output power per port for PD77728ILQ-0111-TR?
The PD77728ILQ-0111-TR guarantees >90W per 4-pair port at VMAIN = 52V, meeting IEEE 802.3bt Type 4 requirements. Under test conditions with VMAIN = 52V and Class 8 single-signature PDs, it delivers up to 100W. This rating is validated across the full –40 °C to +85 °C ambient range with internal thermal protection active. The PD77728ILQ-0111-TR achieves this using integrated 160 mΩ FETs and dual-rail power architecture to minimize conduction loss.
Does PD77728ILQ-0111-TR require external surge protection components?
No - the PD77728ILQ-0111-TR meets IEC61000-4-5-2014 with 2 kV common-mode surge immunity without external protection components. This is achieved through internal robustness in the analog front-end and isolation design. For higher surge levels (e.g., 4–10 kV), Microchip recommends consulting AN4813 for supplemental external TVS/clamp networks. The PD77728ILQ-0111-TR's VMAIN_7 and VMAIN_36 pins allow flexible PCB-level surge path configuration depending on system-level requirements.
How does PD77728ILQ-0111-TR handle short-circuit faults on a powered port?
The PD77728ILQ-0111-TR detects short-circuit conditions within microseconds by monitoring VPORT collapse while in current limit. Upon detection, it disconnects the port within 100 µs (typical) using its integrated FET - preventing MOSFET SOA violation and minimizing energy dissipation. This Real-Time Protection (RTP) action is fully autonomous, implemented in the digital domain, and does not require host intervention. The PD77728ILQ-0111-TR also logs the event via INT_OUT_N and supports automatic retry after configurable delay.
Can PD77728ILQ-0111-TR operate without a host microcontroller?
Yes - the PD77728ILQ-0111-TR supports Unmanaged Auto mode, enabling fully autonomous IEEE 802.3bt-compliant operation without I²C host control. In this mode, it performs detection, classification, power-up, MPS maintenance, and fault recovery independently. The PD77728ILQ-0111-TR retains full functionality including RTP, surge immunity, and thermal protection. Host communication remains optional for advanced features like firmware updates, port reconfiguration, or telemetry reporting.
What is the role of the IREF pin on PD77728ILQ-0111-TR?
The IREF pin (Pin 14) accepts an external 10 kΩ ±0.1% resistor connected to AGND, establishing the precision current reference for all per-port current measurements, classification accuracy, and ILIM/ICUT threshold generation. Its 25–50 ppm/°C temperature coefficient ensures stable performance across –40 °C to +85 °C. Using the specified 0402 resistor minimizes parasitic effects and maintains <±2.5% power accuracy across the 5–100W range. The PD77728ILQ-0111-TR relies exclusively on this external reference for metrological traceability.
PD77728ILQ-0111-TR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 56-VFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Controller (PSE)
- Number of Channels:
- 8
- Power - Max:
- 90 W
- Internal Switch(s):
- Yes
- Auxiliary Sense:
- No
- Standards:
- 802.3at (PoE+), 802.3af (PoE), 802.3bt
- Voltage - Supply:
- 3V ~ 3.6V, 44V ~ 57V
- Current - Supply:
- 1.5mA
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 56-QFN (8x8)
PD77728ILQ-0111-TR FAQ
1.How can I place an order for PD77728ILQ-0111-TR through Aetrix?
Please submit a Request for Quotation (RFQ) for PD77728ILQ-0111-TR 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 PD77728ILQ-0111-TR reliable?
The price and inventory of PD77728ILQ-0111-TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for PD77728ILQ-0111-TR is usually 5 days.
3.What payment methods are accepted for PD77728ILQ-0111-TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for PD77728ILQ-0111-TR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for PD77728ILQ-0111-TR?
PD77728ILQ-0111-TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your PD77728ILQ-0111-TR 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 PD77728ILQ-0111-TR?
For technical support, including PD77728ILQ-0111-TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your PD77728ILQ-0111-TR requirements.
6.How does Aetrix verify that PD77728ILQ-0111-TR is sourced from the original manufacturer or authorized distributors?
All PD77728ILQ-0111-TR 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 PD77728ILQ-0111-TR meets industry standards.
7.What is the process for return or replacement of PD77728ILQ-0111-TR?
All PD77728ILQ-0111-TR units undergo pre-shipment inspection (PSI). If there is an issue with PD77728ILQ-0111-TR, 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 PD77728ILQ-0111-TR part is unused and in its original packaging.
Return procedure for PD77728ILQ-0111-TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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