8 layers126 × 117 mm
4 layers41.8 × 19 mm
Crystal prober
azonenberg/electronics-training15Training materials for classes etc
- Size
- 41.8 × 19 mm
- Copper layers
- 4
- Thickness
- 1.6 mm
- Parts
- 14
- Nets
- 7
- Pads
- 33
- Tracks, vias
- 55, 11
- Pours
- 2
- Routed
- Yes
- KiCad
- KiCad 5 (file 20171130)
- Created
- 14 Nov 2021
- Updated
- 21 Oct 2026
Overview
Crystal prober is an open-source printed circuit board by azonenberg, from the azonenberg/electronics-training repository on GitHub. It is a 4-layer board of 41.8 × 19 mm with 14 parts on 7 nets, routed with 55 tracks and 11 vias.
It is built around the SN74LVC1GX04DCK, ABS07-32.768KHZ-4-T and SMA-J-P-H-ST-EM1. Its parts include 4 capacitors, 4 connectors, 3 resistors, 1 IC and 1 crystal.
Main components
3
SN74LVC1GX04DCK
SC-70-6SC-70-6 Specialty Logic ROHSTexas InstrumentsSpecialty LogicABS07-32.768KHZ-4-T
SMD3215-2P-40℃~+85℃ 32.768kHz 4pF 70kΩ ±30ppm SMD3215-2P Crystals ROHSAbraconCrystals
SMA-J-P-H-ST-EM1
SMD-65℃~+125℃ 1 20GHz 335V 50Ω Board Side Inner pin Positive Pin SMA SMD Coaxial Connectors (RF) ROHSSamtecCoaxial Connectors (RF)
README
oscilloscope-probing/lab/boards/demo-board/README.mdDemo board
info
- ebay xc7a35t-2fgg484i
- stm32h750 running control plane
- 4x LVCMOS33 outputs for low speed stuff, wired direct from FPGA to SMAs
- A few GTPs to SMAs
- ltc3374a based power, usb-c, f234
- Some fast LVCMOS18 or similar outputs
- needs 32 mbit or larger spi flash, load more fw for stm32 from same flash if needed??
stackup: 8 layers SGS PG SGS JLC081611-2116?? going down to 6 probably wont save much
BUGS BUGS BUGS in first board revision
- FT234 is 0.45mm pitch, footprint is 0.5. it should still solder, barely (150um max pin position error, 250um lands w/ 250um gaps)
- No pulldowns on rail enables, so they all turn on without sequencing until the supervisor is flashed and out of reset
- Not really a bug, but should have put DC blocks on PAM3 outputs so we don't need them scope side
- LTC3374A MODE pin is strapped low which causes high ripple on GTY VTT (1.2V) rail due to light load, should have been high
- Add lowpass filter to PAM3 outputs to simulate ethernet magnetics response
- Missing solder paste apertures on USB connector mechanical pins and several PTH headers that could otherwise have been pin-in-paste soldered
NOTE NOTE NOTE Board 3 C122 has 10uf instead of 22
Parts
14| Qty | Value | Footprint | References |
|---|---|---|---|
| 2 | 8 pF | azonenberg_pcb:EIA_0402_CAP_NOSILK | C3, C4 |
| 1 | 0.47 uF | azonenberg_pcb:EIA_0402_CAP_NOSILK | C2 |
| 1 | 1M | azonenberg_pcb:EIA_0402_RES_NOSILK | R1 |
| 1 | 324K | azonenberg_pcb:EIA_0402_RES_NOSILK | R2 |
| 1 | 33 | azonenberg_pcb:EIA_0402_RES_NOSILK | R3 |
| 1 | 4.7 uF | azonenberg_pcb:EIA_0603_CAP_NOSILK | C1 |
| 1 | ABS07-32.768KHZ-4-T | azonenberg_pcb:CRYSTAL_3.2x1.5MM | Y1 |
| 1 | BARREL_JACK | azonenberg_pcb:CONN_CUI_PJ-058BH_HIPWR_BARREL_NOSLOT | J1 |
| 1 | LOGO | azonenberg_pcb:LONGTHING-1200DPI | G*** |
| 1 | SMA-J-P-H-ST-EM1 | azonenberg_pcb:CONN_SMA_EDGE_SAMTEC_SMA_J_P_H_ST_EM1 | J2 |
| 1 | SN74LVC1GX04 | azonenberg_pcb:SOT23_6 | U1 |
| 1 | TESTCLIP | azonenberg_pcb:TESTPOINT_SMT_KEYSTONE_5016 | J4 |
| 1 | TESTPOINT | azonenberg_pcb:TESTPOINT_SMT_0.5MM | J3 |
Questions
How big is the Crystal prober PCB?
It measures 41.8 × 19 mm and has 4 copper layers, 1.6 mm thick.
What parts does the Crystal prober use?
14 parts, built around the SN74LVC1GX04DCK, ABS07-32.768KHZ-4-T and SMA-J-P-H-ST-EM1. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.
Where can I download the Crystal prober KiCad files?
From the azonenberg/electronics-training repository on GitHub, at the commit this page was made from: the board is oscilloscope-probing/lab/boards/crystal-prober/crystal-prober.kicad_pcb and its schematic oscilloscope-probing/lab/boards/demo-board/demo-board.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Crystal prober design in my own project?
Its repository states no licence, so its author keeps all rights: ask azonenberg before reusing the design.
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