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Monolithic Power Systems Inc. MP3924GU-Z
- Part No.:
- MP3924GU-Z
- Manufacturer:
- Monolithic Power Systems Inc.
- Category:
- Power Over Ethernet (PoE) Controllers
- Package:
- 32-VFQFN Exposed Pad
- Datasheet:
-
MP3924GU-Z.pdf
- Description:
- QUAD-PORT, IEEE 802.3AF/AT-COMPL
- Quantity:
- Payment:
- Shipping:
Inventory:1,894
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Product details
Overview
MP3924GU-Z from Monolithic Power Systems is a quad-port IEEE 802.3af/at Power over Ethernet (PoE) power sourcing equipment (PSE) controller IC. It performs full PoE detection, classification (Classes 0–5), current limiting, disconnected load detection, and thermal protection across four independent ports. Integrated 9-bit ADC monitors port voltage/current, and dual interrupt pins (INT1/INT2) support priority-based fault handling in enterprise switches and midspan injectors.
For engineers reviewing the MP3924GU-Z datasheet, MP3924GU-Z pinout, MP3924GU-Z application, or MP3924GU-Z equivalent, key selection criteria include IEEE 802.3at Class 5 enable (CLS5), configurable total power limit via PMAX resistor (up to 120 W), automatic vs. I²C command control mode, and QFN-32 (5mm×5mm) package compatibility with Kelvin-sense layout requirements for 0.25Ω current-sense resistors.
Technical Context
The MP3924GU-Z implements a fully integrated PSE controller architecture compliant with both IEEE 802.3af (15.4W/port) and 802.3at (30W/port) standards, including two-event classification and instantaneous current/voltage readout per port. Its internal 3.3V VCC regulator powers analog/digital circuitry, eliminating need for external LDOs.
It supports isolated communication via three-wire I²C (SCL, SDAO, SDAI) with open-drain outputs and configurable 4-bit I²C address (A0–A3). Dual interrupt outputs (INT1 for all events, INT2 for high-priority faults) enable deterministic system-level response to overcurrent, thermal shutdown, or DC disconnect events.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| IEEE Compliance | Fully compliant with IEEE 802.3af and 802.3at, supporting Class 0–5 PD detection and classification. |
| Port Count | Four independent PoE ports with dedicated GATE/SENSE/OUT pins and shared PGND/DGND/SGND domains. |
| Current Sensing | Uses 0.25Ω high-side sense resistors; supports Kelvin connection for accuracy; ILIM thresholds range 101–278 mV depending on class. |
| ADC Resolution | 9-bit integrated ADC for real-time monitoring of port current (±1.216 A full-scale), voltage (±76.65 V), temperature (−40°C to +164.4°C), and PMAX setting. |
| Power Limit Control | PMAX pin sets total system power limit: 49.9 W (49.9 kΩ), 120 W (120 kΩ), or 204.8 W (floating). |
| Operating Input Range | VIN = 44 V to 57 V; includes UVLO (29.5 V), OVLO (65 V), and input power-ok threshold (40 V). |
| Package | QFN-32 (5 mm × 5 mm, 0.5 mm pitch), thermally enhanced with exposed PGND pad. |
Pinout & Package
MP3924GU-Z is housed in a thermally optimized QFN-32 (5 mm × 5 mm) package with exposed PGND pad for efficient heat dissipation. Pin functions are validated per MPS MP3924 Rev. 1.0 datasheet (July 2021), supporting Kelvin-sense routing and dual-interrupt prioritization.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GATE1–GATE4 | MOSFET gate drivers | Drive external N-channel MOSFETs per port; sink capability up to 9 mA during shutdown; clamp voltage 10 V. |
| SENSE1–SENSE4 | High-side current sense inputs | Accept voltage drop across 0.25Ω sense resistor; bias current ±1 µA; require Kelvin PCB routing for accuracy. |
| OUT1–OUT4 | Output voltage sense returns | Connect to PD return path for detection, classification, foldback control, and PG status; 0.2 MΩ internal pull-up. |
| INT1 / INT2 | Open-drain interrupt outputs | INT1 signals all events; INT2 latches high-priority faults only; both require external 4.7 kΩ pull-up to VCC. |
| SCL / SDAO / SDAI | I²C interface pins | Three-wire isolated I²C: SCL clock, SDAO output, SDAI input; all open-drain with 4.7 kΩ pull-up recommended. |
| PMAX | Total system power limit setting | Resistor-to-DGND sets aggregate 4-port power cap: 49.9 kΩ → 49.9 W; 120 kΩ → 120 W; floating → 204.8 W. |
| CLS5 | Class 5 enable input | Pulled down internally; connect to VCC to activate IEEE 802.3at Class 5 (up to 60 W) classification mode. |
| AUTO | Startup mode select | Pulled up internally; float for automatic operation; tie to DGND for default shutdown mode. |
Key Features
| Feature | Design Value |
|---|---|
| Quad-port IEEE 802.3af/at compliance | Full detection, classification (0–5), current limiting, and disconnected load detection on all four ports without external logic. |
| Configurable total power limit | Single PMAX resistor sets system-wide power ceiling (49.9 W to 204.8 W), preventing overloading of upstream DC supply. |
| Dual interrupt priority architecture | INT2 handles critical faults (e.g., thermal shutdown, SCP) with higher priority than general INT1 events, simplifying host MCU ISR design. |
| Integrated 9-bit ADC with multi-channel monitoring | Simultaneously reads per-port current, voltage, die temperature, and PMAX setting-enabling real-time telemetry and adaptive power management. |
| Isolated three-wire I²C interface | SCL/SDAO/SDAI pins support galvanically isolated communication using optocouplers or digital isolators, meeting safety requirements in midspan applications. |
| Automatic and software-controlled operation modes | Auto mode enables plug-and-play deployment; I²C command mode allows dynamic reconfiguration (e.g., port enable/disable, class override) post-power-up. |
Applications
| Enterprise Network Switches | Midspan PoE Injectors |
|---|---|
|
Use Scenario: 24- or 48-port managed Ethernet switch delivering PoE to IP phones, wireless APs, and security cameras. IC Role / Device Role / Timing Role: Primary PSE controller managing all four port groups; executes IEEE-compliant detection/classification within 310 ms per port. Use Value: Enables concurrent powering of mixed-class devices (e.g., Class 2 phones + Class 4 cameras) while enforcing total system power budget via PMAX resistor. |
Use Scenario: Standalone 4-port midspan injector adding PoE capability between legacy switch and non-PoE endpoints. IC Role / Device Role / Timing Role: Standalone PSE controller with MID pin enabling midspan-specific re-detection delay (2.8 s); supports isolated I²C for host MCU separation. Use Value: Eliminates need for external isolation components by integrating three-wire I²C; CLS5 pin enables Class 5 support for high-power access points. |
| Surveillance NVR/DVR Systems | Industrial IoT Gateways |
|
Use Scenario: Rack-mounted NVR powering eight PoE-enabled PTZ cameras via two MP3924GU-Z controllers. IC Role / Device Role / Timing Role: Quad-port PSE managing camera power sequencing; uses DC disconnect detection to identify unplugged or failed cameras. Use Value: Reduces false alarms via accurate 1.25–2.5 mV DC hold threshold and 300–400 ms disconnect timing, improving system reliability. |
Use Scenario: Ruggedized gateway powering sensors, actuators, and edge AI modules in factory automation networks. IC Role / Device Role / Timing Role: PSE controller operating at −40°C to +125°C junction temperature; provides thermal shutdown (150°C) and hysteresis (25°C) for harsh environments. Use Value: Ensures continuous operation under wide ambient swings; 9-bit ADC enables predictive maintenance via real-time temperature and current trend logging. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar PoE PSE controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| Microchip LAN9303-ABZ | Triple-port 802.3af-only controller; no 802.3at Class 5 support; integrates 3-port switch fabric; requires external current-sense amps. | Limited to lower-power endpoints (≤15.4 W/port); suited for cost-sensitive SOHO switches where switching + PSE integration reduces BOM count. | Select when integrated switch functionality is required and Class 5 power is unnecessary; verify external sensing accuracy meets system tolerance. |
| Analog Devices LT4275AIMSE#PBF | Single-port 802.3af/at controller; supports Class 5; includes integrated hot-swap MOSFET driver; no multi-port coordination or PMAX system limit. | Requires four separate ICs for quad-port design; lacks built-in total power capping; better suited for modular or distributed PSE architectures. | Choose for designs needing highest per-port reliability with integrated FET drive and robust surge protection; accept higher component count and layout complexity. |
Compared with LAN9303-ABZ and LT4275AIMSE#PBF, MP3924GU-Z uniquely delivers quad-port 802.3at Class 5 compliance with single-resistor system-level power limiting and integrated ADC telemetry-reducing firmware overhead and PCB area in centralized PSE systems.
Availability
MP3924GU-Z is available at Aetrix Electronics and suitable for enterprise network switches, midspan PoE injectors, and surveillance NVR/DVR systems requiring stable component supply, long-term lifecycle support, and RoHS-compliant manufacturing.
Supply support for MP3924GU-Z 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
Monolithic Power Systems (MPS) is a fabless semiconductor company specializing in high-performance power management ICs, with core expertise in DC/DC converters, LED drivers, motor drivers, and PoE solutions.
The MP3924 belongs to MPS's PoE PSE controller product line, designed specifically for centralized, multi-port IEEE 802.3af/at power sourcing in enterprise infrastructure and industrial networking equipment.
FAQ
What is the maximum total power limit supported by MP3924GU-Z?
The MP3924GU-Z supports three total power limit configurations via the PMAX pin: 49.9 W (with 49.9 kΩ resistor to DGND), 120 W (with 120 kΩ resistor), or 204.8 W (PMAX pin left floating). This limit applies across all four ports simultaneously and is enforced by internal power monitoring circuitry.
Does MP3924GU-Z support IEEE 802.3bt (PoE++)?
No. MP3924GU-Z is certified for IEEE 802.3af (Type 1) and 802.3at (Type 2) only, supporting up to Class 5 (60 W). It does not implement 4-pair power delivery, autoclass, or higher-power classification protocols defined in 802.3bt (Type 3/4).
How is Class 5 enabled on MP3924GU-Z?
Class 5 operation is enabled by connecting the CLS5 pin to VCC. The pin is internally pulled down to DGND through a 50 kΩ resistor; leaving it unconnected disables Class 5. CLS5 state is latched at startup or reset and cannot be changed dynamically during operation.
What is the purpose of the dual interrupt pins (INT1 and INT2)?
INT1 signals all enabled interrupt sources (e.g., overcurrent, thermal fault, DC disconnect). INT2 is reserved for high-priority events only (e.g., thermal shutdown, short-circuit protection), allowing host MCUs to prioritize critical responses without polling multiple registers.
Can MP3924GU-Z operate in both automatic and I²C-controlled modes simultaneously?
No. The AUTO pin selects the default startup mode: floating enables automatic operation; tied to DGND forces shutdown mode. Once powered, I²C commands can override port states (enable/disable, class change), but the base operational mode (auto vs. manual) is fixed at power-on and cannot be toggled dynamically.
What is the recommended current-sense resistor value and layout practice?
MPS specifies a 0.25 Ω high-side sense resistor for all ports. For accuracy, Kelvin connections are mandatory: SENSEn must connect directly to the resistor's high-side terminal, and SGND1/SGND2 must connect to the low-side terminal using separate traces-avoiding shared return paths that introduce offset errors.
Is the internal VCC regulator sufficient to power external circuitry?
The internal 3.3 V regulator (VCC pin) supplies only the MP3924GU-Z's internal analog and digital circuits (max 15 mA load). It is not rated to power external components such as microcontrollers or isolators; those require a separate regulated supply.
MP3924GU-Z Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Monolithic Power Systems Inc.
- Series:
- -
- Package/Case:
- 32-VFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Controller (PSE)
- Number of Channels:
- 4
- Power - Max:
- -
- Internal Switch(s):
- No
- Auxiliary Sense:
- No
- Standards:
- 802.3at (PoE+), 802.3af (PoE)
- Voltage - Supply:
- 44V ~ 57V
- Current - Supply:
- 2mA
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 32-QFN (5x5)
MP3924GU-Z FAQ
1.How can I place an order for MP3924GU-Z through Aetrix?
Please submit a Request for Quotation (RFQ) for MP3924GU-Z 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 MP3924GU-Z reliable?
The price and inventory of MP3924GU-Z are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MP3924GU-Z is usually 5 days.
3.What payment methods are accepted for MP3924GU-Z?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MP3924GU-Z transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MP3924GU-Z?
MP3924GU-Z orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MP3924GU-Z 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 MP3924GU-Z?
For technical support, including MP3924GU-Z datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MP3924GU-Z requirements.
6.How does Aetrix verify that MP3924GU-Z is sourced from the original manufacturer or authorized distributors?
All MP3924GU-Z 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 MP3924GU-Z meets industry standards.
7.What is the process for return or replacement of MP3924GU-Z?
All MP3924GU-Z units undergo pre-shipment inspection (PSI). If there is an issue with MP3924GU-Z, 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 MP3924GU-Z part is unused and in its original packaging.
Return procedure for MP3924GU-Z:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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