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Contents

README

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LAN7850T-I

Microchip Tech · Ethernet Controllers · QFN-56-EP(8x8)

LAN7850T-I from Microchip Tech, in a QFN-56-EP(8x8). 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 TR0P bidirectional Gigabit Ethernet transmit/receive positive channel 0 (AIO).
2 TR0N bidirectional Gigabit Ethernet transmit/receive negative channel 0 (AIO).
3 VDD25A power_in +2.5V analog supply input for Gigabit Ethernet PHY.
4 TR1P bidirectional Gigabit Ethernet transmit/receive positive channel 1 (AIO).
5 TR1N bidirectional Gigabit Ethernet transmit/receive negative channel 1 (AIO).
6 VDD25A power_in +2.5V analog supply input for Gigabit Ethernet PHY.
7 TR2P bidirectional Gigabit Ethernet transmit/receive positive channel 2 (AIO).
8 TR2N bidirectional Gigabit Ethernet transmit/receive negative channel 2 (AIO).
9 VDD25A power_in +2.5V analog supply input for Gigabit Ethernet PHY.
10 TR3P bidirectional Gigabit Ethernet transmit/receive positive channel 3 (AIO).
11 TR3N bidirectional Gigabit Ethernet transmit/receive negative channel 3 (AIO).
12 VDD25A power_in +2.5V analog supply input for Gigabit Ethernet PHY.
13 VDDVARIO power_in +1.8V to +3.3V variable I/O supply.
14 TDI input JTAG test data input (VIS buffer).
15 TDO output JTAG test data output (O12 buffer).
16 TCK/GPIO0 bidirectional JTAG test clock, alternate function GPIO0. Max clock is half the system clock.
17 TMS input JTAG test mode select (VIS buffer).
18 VDD12_SW_OUT power_out +1.2V output voltage from integrated switching regulator.
19 VDD_SW_IN power_in +3.3V input voltage for the integrated switching regulator.
20 VDD12_SW_FB passive Feedback pin for integrated switching regulator. Tie to VDD_SW_IN to disable the switcher.
21 EECS/GPIO1 output External EEPROM chip select output (O12). Alternate function GPIO1.
22 EEDI/GPIO2 input External EEPROM data input (driven by EEPROM DO). Alternate function GPIO2.
23 EEDO/GPIO3 output External EEPROM data output driving EEPROM DI (O12). Alternate function GPIO3.
24 EECLK/GPIO4 output External EEPROM clock output (O12). Alternate function GPIO4.
25 VDDVARIO power_in +1.8V to +3.3V variable I/O supply.
26 VDD12CORE power_in +1.2V digital core power supply input.
27 VBUS_DET input Detects state of upstream USB bus power (VIS with pull-down). For bus-powered operation tie to VDD33A.
28 SUSPEND_N/GPIO5 output Asserted when device is in a suspend state (O12). May control an external switcher. Alternate function GPIO5.
29 CONNECT/GPIO6 output USB CONNECT output - asserts when device is attempting to attach to USB host (O12). Alternate function GPIO6.
30 HSIC_SEL input HSIC select: tie to VDD to enable HSIC interface, otherwise USB 2.0 interface is enabled. Static signal, do not change at runtime.
31 LED0/GPIO7 output Indicator LED0 (OD12), configurable for link/activity/duplex/collision. Alternate function GPIO7.
32 PME_MODE/GPIO8 input PME mode selection input when PME mode is active (VIS). Alternate function GPIO8.
33 VDD12A power_in +1.2V analog supply input for USB PLL/AFE.
34 VDD12HSIC power_in +1.2V HSIC power supply input.
35 STROBE bidirectional HSIC bi-directional data strobe signal per HSIC Electrical Specification.
36 USB_DP bidirectional Hi-Speed USB 2.0 D+ data line (AIO).
37 USB_DM bidirectional Hi-Speed USB 2.0 D- data line (AIO).
38 DATA bidirectional HSIC bi-directional DDR data signal, synchronous to STROBE.
39 PME_N output Active-low PME signal output (O8/OD8), asserted during PME operation.
40 TEST input Test pin, for internal purposes only. Must be tied to ground for proper operation.
41 RESET_N/PME_CLEAR input Active-low system reset (VIS). Also serves as PME clear input when PME mode is active. Pull up to VDD if unused.
42 VDDVARIO power_in +1.8V to +3.3V variable I/O supply.
43 USBRBIAS passive USB HS bias reference. Connect to external 12kΩ 1.0% resistor to ground to set HS transmit current and on-chip termination.
44 VDD33A power_in +3.3V analog supply for USB 2.0 AFE.
45 VDDVARIO power_in +1.8V to +3.3V variable I/O supply.
46 XI input External 25 MHz crystal input. May also be driven by a single-ended clock oscillator (leave XO open).
47 XO output External 25 MHz crystal output. Leave unconnected if XI is driven by an external oscillator.
48 VDD12CORE power_in +1.2V digital core power supply input.
49 LED1/GPIO9 output Indicator LED1 (OD12), configurable for link/activity/duplex/collision. Alternate function GPIO9.
50 LED2/GPIO10 output Indicator LED2 (OD12), configurable for link/activity/duplex/collision. Alternate function GPIO10.
51 LED3/GPIO11 output Indicator LED3 (OD12), configurable for link/activity/duplex/collision. Alternate function GPIO11.
52 VDD12A power_in +1.2V analog supply input for USB PLL/AFE.
53 VDD25_REG_OUT power_out +2.5V output from integrated LDO used to supply Gigabit Ethernet PHY AFE.
54 VDD33_REG_IN power_in +3.3V input supply to integrated LDO.
55 REF_REXT passive External PHY reference resistor. Connect to external 2kΩ 1.0% resistor to ground.
56 REF_FILT passive External PHY reference filter. Connect to external 1µF capacitor to ground.
57 VSS power_in Exposed thermal pad. Common ground; must be connected to ground for proper operation and thermal performance.

Key specifications

Parameter Value
Manufacturer Microchip Tech
Package QFN-56-EP(8x8)
Category Interface
Pins 57

Ordering variants

Same part, different packaging or reel option.

  • LAN7850T-I
  • LAN7850T-I/YZX

CAD (KiCad official)

  • Symbol: LAN7850T-I
  • Footprint: Package_DFN_QFN:QFN-56-1EP_8x8mm_P0.5mm_EP4.5x5.2mm
  • 3D model: QFN-56-EP(8x8) (KiCad packages3D, STEP)
  • 3D model files: lan7850t-i-etched.step / lan7850t-i-etched.glb carry the MPN laser-etched on the die in a toggleable Adom.LaserEtch group (Fusion-ready); lan7850t-i.step / lan7850t-i.glb are the bare package body.

Provenance

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

  • Datasheet: Microchip Tech datasheet (277 pp, sha256 41b2cc2942c4219b, 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