I want to built a USB 2 hub using the USB2514B con...

collinsemasi

flux

I want to built a USB 2 hub using the USB2514B controller from microchip. I linked relevent documents in the Reference Document file. Generate a product requirements doc, a design spec for schematic capture, a component selection and BOM tracker, a design review template, a test and validation plan, and a DFM checklist for pre-production.
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Schematic Design Specification
1. Core IC
  • Hub controller: USB2514B, 4-port USB 2.0 hub
  • Preferred package for new designs: 36-pin SQFN
2. Required Schematic Blocks
2.1 Hub Core Power
  • Connect all VDD33 and VDDA33 pins to regulated 3.3 V
  • Place 0.1 uF decoupling capacitors close to each power pin:
    • VDDA33 pins: one 0.1 uF per pin
    • VDD33 pins: one 0.1 uF per pin
  • Add 1.0 uF shared bulk capacitance on the 3.3 V rail local to the hub
  • Tie the exposed pad/ePad to ground with multiple vias
  • Use one common solid ground plane; separate analog/digital ground planes are not recommended
2.2 Core Analog Support
  • RBIAS pin: connect 12.0 kOhm, 1% resistor to ground, placed very close to the pin
  • CRFILT pin: may connect up to 0.1 uF low-ESR capacitor to ground, or may be left unconnected
  • PLLFILT pin: may connect up to 0.1 uF low-ESR capacitor to ground, or may be left unconnected
  • TEST pin: treat as no-connect or tie to ground; do not route signals to it
  • NC pins: no connect, no routing
2.3 Clock Circuit
  • Use 24.000 MHz ±350 ppm crystal or external 24 MHz clock
  • If using crystal:
    • connect between XTALIN and XTALOUT
    • size C1/C2 to the crystal load requirement
    • keep crystal loop compact and isolated from USB traces
  • If using external clock:
    • drive XTALIN/CLKIN only
    • leave XTALOUT unconnected
2.4 Reset Circuit
  • RESET_N must be held low for at least 1 us after all supplies are within operating range
  • Recommended power-up reset network from hardware checklist:
    • 10 kOhm pull-up to 3.3 V
    • 1 uF capacitor to ground
  • Errata workaround for SMBus/DP power-up glitch:
    • keep RESET_N low during POR using external control or RC network
    • errata example values: 100 kOhm pull-up to 3.3 V and 220 nF capacitor to ground
  • Preferred implementation for robust designs: reset supervisor or MCU-controlled reset with timing validation
2.5 Upstream USB Port
  • Connect USBDP_UP and USBDM_UP directly to the upstream USB connector D+ and D-
  • Connect VBUS_DET to upstream VBUS through a 2:1 divider; suggested values are 100 kOhm / 100 kOhm
  • Upstream VBUS capacitance shall not exceed 10 uF total
  • Tie connector ground to PCB ground with low impedance
  • Connector shield: recommended RC network to PCB ground using 330 Ohm || 0.1 uF
2.6 Downstream USB Ports
  • Connect each USBDP_DNx / USBDM_DNx pair directly to the downstream connector data pins
  • For any unused downstream port, disable the port by pulling both D+ and D- strap functions high to 3.3 V, or disable by EEPROM/SMBus configuration
  • Each exposed downstream port shall include:
    • VBUS power switch / port power controller
    • over-current fault reporting to OCS_Nx
    • downstream VBUS bulk capacitance up to 150 uF max per Microchip reference circuit
2.7 Port Power Controller Interface
  • PRTPWRx should drive a controller enable input that is active-high and compatible with 3.3 V logic
  • OCS_Nx should receive an active-low, open-drain FAULT indication
  • If controller polarity or voltage is incompatible, add external inversion or level adaptation
2.8 Strap / Configuration Pins
  • Define CFG_SEL pins based on selected configuration mode:
    • 00: default config, self-powered default, individual switching, individual OC sensing, straps enabled
    • 01: SMBus configuration
    • 10: default config override for bus-powered operation
    • 11: I2C EEPROM configuration
  • Non-removable ports shall be strapped or configured for permanently attached devices
  • Battery charging enable straps shall be implemented only on ports whose power path supports the required current
  • LED/shared strap pins shall follow the strap resistor guidance of 47 kOhm to 100 kOhm where applicable
2.9 Optional EEPROM / SMBus
  • EEPROM interface requires external pull-ups on SDA and SCL to VDD33; 10 kOhm recommended
  • EEPROM must be 256 x 8-bit organization
  • Hub reads EEPROM only; it does not program EEPROM
  • If SMBus is selected, EEPROM mode is not available on the shared pins
3. Schematic Review Gates
  • Pinout matches package and datasheet
  • All power pins decoupled per checklist
  • All exposed ports have VBUS switching and OC reporting
  • Reset strategy documented and consistent with errata workaround
  • Unused ports explicitly disabled
  • Configuration mode documented
  • Battery charging ports explicitly identified and power-sized

  • 1. Core IC

  • 2. Required Schematic Blocks

  • 2.1 Hub Core Power

  • 2.2 Core Analog Support

  • 2.3 Clock Circuit

  • 2.4 Reset Circuit

  • 2.5 Upstream USB Port

  • 2.6 Downstream USB Ports

  • 2.7 Port Power Controller Interface

  • 2.8 Strap / Configuration Pins

  • 2.9 Optional EEPROM / SMBus

  • 3. Schematic Review Gates

Datasheets & reference material: Files, Datasheet & Reference Material Demo Project

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