Gsw141-breakout

GSW141 Switch Chip Breakout

Different Arrangements of the GSW141 Breakout PCB?

RJ45 Jacks

• Internal Magnetics | External Magnetics
• LEDs | No LEDs
• 1000 (or higher) Base-T
  • I think 1G capable means that there are 4 twisted pairs
• "Tab Up" | "Tab Down"
  • This means the tab on the cable. When tab is down, the cat-5 pins all in a row point "up", and vise versa when tab is up.
  • The GSW141 chip routes traces best with "tab down"
  • "Tab up" + on the reverse side of the board is equivalent to "tab down"
• How many ports per part

Internal Magnetics

Use ARJM11C7-502-KB-EW2 on mouser

• Tab up, so would have to be placed on the reverse side of the PCB
• $3.09 @ 10

4x 1 unit = $12.36

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Use TMJG26945AENL on mouser, 1x2 port

• Tab down
• $11.34 per unit

2x 1 unit = $22.68

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Use TMJG46945AENL on mouser, 1x4 port

• Tab down
• $18.84 per unit

External Magnetics

• Mouser 1149848 4 port RJ45 w/ LEDs, $4.34 each
  • Tab up, so would have to be placed on PCB reverse side
• Mouser LAN2VSOD48351C2 dual port magnetics chip, ~$2 each

1 @ 4.34 + 2 @ $2 = $8.34

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• Mouser 1149854 2 port RJ45 w/LEDs, $2.78 each
  • Tab up, reverse PCB side
• Mouser LAN2VSOD48351C2 dual port magnetics chip, ~$2 each

2 @ 2.78 + 2 @ 2 = $9.56

Board Questions

[ ] How should the 1000 Base T diff pairs be terminated into the magnetics?

Board TODO

[x] 4 port RJ45 jack [x] RJ45 LEDs [x] Management Interface * SPI, etc * Pin headers [x] Strapping pins? * 206-125ST on mouser * or DS01C-254-L-09BE [x] GPIO Pins, header [x] RGMII/SGMII over edge connctor [x] RGMII/SGMII header [x] Remove these headers actually [x] Power regulation, 3.3V, 1.1V [x] Power jack (latching) and jack * Mouser T6634ST barrel connector * 5.5 mm (out) x 2.1 mm (in) * Out 0v, inside, pos * Barrel Jack: 694106301002 for above [x] Clock input * ECS-400-12-33B2Q-JES-TR3 on mouser * Clock circuit cap calculation comes from https://blog.adafruit.com/2012/01/24/choosing-the-right-crystal-and-caps-for-your-design/ * CL = C1 * C2 / (C1 + C2) + Cstray * Cstray is ~3 pF * If C1 = C2 = C, and CL = 12 pF for the above crystal * so C = 2(CL - Cstray) => C = 18 pF [x] Power switch, latching * Digikey PB400EEQR1BLK maybe? [x] Reset Button * button TS21-34-035-BK-160-SMT-TR on mouser [ ] Power indicator LEDs [x] GSW Power Startup sequence * RC delay from 3.3 V into 1.1V enable [ ] Make sure trace clearance is okay [ ] Power off? [x] Power Caps on GSW chip [x] Blank R for RESREF and RCAL [ ] Fix the RJ45 / magnetic pinout alignment so routing is easier [ ] Diff Pairs that are off by more than 10s of mm should be length tuned [ ] Empty Footprint for linear regulator(s)? [ ] TI 1G checklist https://www.ti.com/lit/an/snla387/snla387.pdf?ts=1720391456901