Note – these are all marked PRELIMINARY, so people should use at their own risk. We will be testing these boards by the end of November. The difference lists are on the last page of the schematics, and listed below. Since we didn’t build D or E, roll the D, E, and F lists together to compare Rev F to Rev C.
Revision C Changes:
1) Add Silkscreen Logos - CE, RoHS and Copper Part Number on board
2) Reduce R34, 35, (40), 42 from 100K to 1K
3) Add pulldown resistors to R34, 35, (40), 42 - Value 2.2K - 5.00K
4) Fuse (PTC) recommendation note for R50, 12V input
5) Connect: U8.6 to U20.2
6) Connect: U3.16 to U8.3
7) Connect: JX2.10 to U15.4
8) Change 4.75K resistors to 4.99K
9) Added rubber feet to BOM
10) Add staple point vias for J2 USB connector.
Revision D Changes (no production):
1) Attached JX2.10 to U15.4
Revision E Changes (no production):
1) Replaced U1 from MAX13035EETE+ to TI TXS02612ZQSR part.
2) Added Sheet 11.
3) Moved mechanical information to back page.
Revision F Changes:
1) Changed USB UART default power to bus power. Attach VBUS power net to U2.7 REGIN pin. Disconnect Vdd pin from +3.3V.
2) Added Ethernet LED drive buffer circuit to reduce 3.3V PHY backfeed.
3) Added: D10, D11, JT7, R97, R98 to allow user to configure USB Bus or Self power mode.
4) Removed two fansink mounting holes. Removed ground attribute to mounting holes (in layout files).
5) Added D12 PolyZen (PTC+Zen) USB UART protection component as configurable option.
6) Added R99 0 ohm resistor for D12 bypass (default).
7) Added C221 2.2uF capacitor for USB transient and flyback voltage protection.
8) Revised notes (above).