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README

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MP3924GU-Z

Monolithic Power Systems · Power Over Ethernet (PoE) Controllers · QFN-32(5x5)

MP3924GU-Z from Monolithic Power Systems, in a QFN-32(5x5). Pinout and pin descriptions extracted from the manufacturer datasheet by ds2sf; symbol, footprint, and 3D from KiCad-official CAD.

Pinout

Pin Name Type Function
1 GATE1 output MOSFET gate driver for port 1. Drives the external pass N-MOSFET for port 1. Float if not used.
2 OUT1 input Output voltage sense pin for port 1. Connect to the output interface return for detection, classification, voltage sensing, and current-limit foldback control. Float if not used.
3 INT2 output High-priority interrupt request pin. Open-drain output that pulls low when the selected high-priority interrupt source register is set and the interrupt is enabled. Tie to DGND if unused. Max sink 20mA (5mA recommended).
4 SGND1 input Current-sense negative input for port 1 and port 2. Connect to the low-side terminal of the sense resistor with a Kelvin connection. Tie to DGND if unused.
5 CLS5 input Class 5 enable input. Internally pulled down to DGND via 50kΩ. Leave floating to disable Class 5 classification (802.3at-compliant); tie to VCC to enable Class 5 devices. Status latched at start-up/reset.
6 AUTO input Automatic mode setting pin. Internally pulled up to VCC via 50kΩ. Float for automatic mode (default), tie to DGND for default shutdown mode. Status latched at start-up/reset.
7 MID input Midspan mode setting pin. Internally pulled up to VCC via 50kΩ. Float for midspan mode (re-initiate detection every 2.8s), tie to DGND to disable midspan mode. Status latched at start-up/reset.
8 INT1 output Interrupt request pin for all interrupt source events. Open-drain output; pulls low when the interrupt register is set and interrupts are enabled. Tie to DGND if unused. Max sink 20mA (5mA recommended).
9 SCL input I2C clock input pin. Requires external pull-up (typically 4.7kΩ) to VCC. Tie to VCC if I2C interface is not used.
10 SDAO output I2C serial data output pin (open-drain). Requires external pull-up (typically 4.7kΩ) to VCC. Connect SDAO to SDAI for non-isolated applications. Tie to DGND if I2C unused. Max sink 20mA.
11 SDAI input I2C serial data input pin. Requires external pull-up (typically 4.7kΩ) to VCC. Connect SDAI to SDAO for non-isolated applications. Tie to DGND if I2C unused.
12 EN input Enable input. Turns all internal circuits and four ports (except the VCC regulator) on/off. Tie EN to VCC to enable the device automatically. VHI ≥ 2.5V, VLI ≤ 0.4V.
13 A0 input I2C address setting pin (LSB). Tie to VCC or DGND to set the lower 4 address bits (address = 010 A3 A2 A1 A0). Latched at start-up/reset. Internally pulled up to VCC via 50kΩ.
14 A1 input I2C address setting pin. Tie to VCC or DGND to set the lower 4 address bits. Latched at start-up/reset. Internally pulled up to VCC via 50kΩ.
15 A2 input I2C address setting pin. Tie to VCC or DGND to set the lower 4 address bits. Latched at start-up/reset. Internally pulled up to VCC via 50kΩ.
16 A3 input I2C address setting pin (MSB of lower nibble). Tie to VCC or DGND to set the lower 4 address bits. Latched at start-up/reset. Internally pulled up to VCC via 50kΩ.
17 DGND power_in Ground of the internal digital and analog circuit.
18 SGND2 input Current-sense negative input for port 3 and port 4. Connect to the low-side terminal of the sense resistor with a Kelvin connection. Tie to DGND if unused.
19 PGND power_in Ground of the input power supply.
20 VCC power_out 3.3V internal regulator output for analog and digital circuit supply. Requires a minimum 1µF ceramic capacitor to DGND. Current limit ≈17mA.
21 PMAX input Maximum loading power setting pin. Connect a resistor from PMAX to DGND to set the total power capability across all four output ports. PMAX setting latched at start-up/reset.
22 VIN power_in Power supply input for both VCC regulator and output ports. Recommended operating range 44V to 57V (absolute max 80V). Bypass with at least 0.1µF/100V ceramic between VIN and PGND.
23 SENSE4 input Current-sense pin from the high-side sense resistor terminal for port 4. Recommended 0.25Ω sense resistor with Kelvin connection. Tie to DGND if unused.
24 GATE4 output MOSFET gate driver for port 4. Drives the external pass N-MOSFET for port 4. Float if not used.
25 OUT4 input Output voltage sense pin for port 4. Connect to the output interface return for detection, classification, voltage sensing, and current-limit foldback control. Float if unused.
26 SENSE3 input Current-sense pin from the high-side sense resistor terminal for port 3. Recommended 0.25Ω sense resistor with Kelvin connection. Tie to DGND if unused.
27 GATE3 output MOSFET gate driver for port 3. Drives the external pass N-MOSFET for port 3. Float if not used.
28 OUT3 input Output voltage sense pin for port 3. Connect to the output interface return for detection, classification, voltage sensing, and current-limit foldback control. Float if unused.
29 SENSE2 input Current-sense pin from the high-side sense resistor terminal for port 2. Recommended 0.25Ω sense resistor with Kelvin connection. Tie to DGND if unused.
30 GATE2 output MOSFET gate driver for port 2. Drives the external pass N-MOSFET for port 2. Float if not used.
31 OUT2 input Output voltage sense pin for port 2. Connect to the output interface return for detection, classification, voltage sensing, and current-limit foldback control. Float if unused.
32 SENSE1 input Current-sense pin from the high-side sense resistor terminal for port 1. Recommended 0.25Ω sense resistor with Kelvin connection. Tie to DGND if unused.

Key specifications

Parameter Value
Manufacturer Monolithic Power Systems
Package QFN-32(5x5)
Category Power Management (PMIC)
Pins 32

Ordering variants

Same part, different packaging or reel option.

  • MP3924GU-Z

CAD (KiCad official)

  • Symbol: MP3924GU-Z
  • Footprint: Package_DFN_QFN:QFN-32-1EP_5x5mm_P0.5mm_EP3.3x3.3mm
  • 3D model: QFN-32(5x5) (KiCad packages3D, STEP)

Provenance

Data extracted from the manufacturer datasheet, not a distributor listing:

  • Datasheet: Monolithic Power Systems datasheet (56 pp, sha256 e746f450cbdd2478, retrieved 2026-08-17, tier: lcsc)
  • Extractor: ds2sf (Claude). Every pin and dimension is cited to a datasheet page; it refuses to fabricate.
  • CAD: KiCad official libraries (CC-BY-SA 4.0).

Datasheet PDF