2 layers98 × 98 mm
CoilSafety
WasabiMushyPeas/coilSafetyCircuit
An electromagnet safety circuit for Dr. Biedermann's Lab.
24 parts1
4 layers63.5 × 100 mm
Distribution amp
thinkfat/dist-amp410MHz Distribution Amplifier (4 channels)
- Size
- 63.5 × 100 mm
- Copper layers
- 4
- Thickness
- 1.6 mm
- Parts
- 42
- Nets
- 23
- Pads
- 142
- Tracks, vias
- 253, 342
- Pours
- 4
- Routed
- Yes
- KiCad
- KiCad 5 (file 20171130)
- Created
- 9 Jan 2021
- Updated
- 12 Jan 2021
Overview
Distribution amp is an open-source printed circuit board by thinkfat, from the thinkfat/dist-amp repository on GitHub. It is a 4-layer board of 63.5 × 100 mm with 42 parts on 23 nets, routed with 253 tracks and 342 vias.
It is built around the 1N4148WS and PJ-037BH. Its parts include 16 capacitors, 9 resistors, 6 connectors, 2 ICs and 2 inductors. It belongs with the audio and music boards of this library.
Main components
2README
README.mddist-amp
This repository contains a 10MHz Distribution Amplifier (4 channels). It's use is mainly in electronics labs or ham radio shacks for distributing a 10MHz frequency standard (GPSDO, Rb atomic clock).
The circuit is based on a design by W. H. Rech, DF9IC, with minor modifications by myself.
Documenation
The doc folder contains the schematic in PDF format. It also contains S11/S21 measurements done with a NanoVNA V2plus4 (nanovna-saver screenshot):
- Maximum input: 10dBm into 50 Ohm
- Cut-off frequency (-3dB): 13.8MHz
- Roll-off: 38dB/octave
- S11 @ 10MHz: -27dB
- S21 @ 10MHz: -0.7dB
Switching the ports I got also:
-
S12 @ 10MHz: < -90dB
In other words, the VNA cannot measure it. The dynamic range is not big enough.
Fabrication
The fab folder contains Gerber plots, a drill file and CPL+BOM files for JLCPCB SMT service. If you want to recreate the board, remember to enable impedance control and choose the JLC7628 PCB stack-up.
BOM
The bom folder contains an interactive HTML BOM you can open in a browser. It will help with sourcing parts and assembling the PCB. Most parts are generic, but some parts must meet either footprint or electrical constraints.
- L1, L2: Johanson Technology L-15F1R0JV4E
- U2: Maxim MAX4022ESD+
- J6: CUI PJ-037BH
- C13-C15: use MLCC capacitors with C0G/NP0 dielectric
Customization
The MAX4022ESD+ has a much larger bandwidth than the 12MHz imposed by the input filter. One obvious modification is therefore to choose a higher roll-off frequency for the input low-pass. Note that total bandwidth and flatness will also depend on parameters of other components in the signal path, notably coupling capacitors at in and output. These are currently generic 100nF MLCC with X7R dielectric. For more demanding applications, you might need to find better ones.
Parts
42| Qty | Value | Footprint | References |
|---|---|---|---|
| 10 | 100n | Capacitor_SMD:C_0805_2012Metric_Pad1.18x1.45mm_HandSolder | C1, C4, C5, C6, C7, C9, C10, C11, C12, C16 |
| 6 | 49.9 | Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R1, R3, R5, R6, R7, R9 |
| 5 | Conn_Coaxial | Connector_Coaxial:SMA_Amphenol_132203-12_Horizontal | J1, J2, J3, J4, J5 |
| 4 | MountingHole_Pad | MountingHole:MountingHole_3.2mm_M3_Pad_Via | H1, H2, H3, H4 |
| 3 | 10u | Capacitor_SMD:CP_Elec_5x5.4 | C2, C3, C8 |
| 2 | 10k | Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R2, R4 |
| 2 | 1u | Inductor_SMD:L_0805_2012Metric_Pad1.05x1.20mm_HandSolder | L1, L2 |
| 2 | 220p | Capacitor_SMD:C_0805_2012Metric_Pad1.18x1.45mm_HandSolder | C13, C15 |
| 1 | 1N4148WS | Diode_SMD:D_SOD-323 | D1 |
| 1 | 470p | Capacitor_SMD:C_0805_2012Metric_Pad1.18x1.45mm_HandSolder | C14 |
| 1 | 4k7 | Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R8 |
| 1 | Logo_Open_Hardware_Large | Symbol:OSHW-Logo2_14.6x12mm_Copper | OSHW1 |
| 1 | MAX4022ESDT | Package_SO:SOIC-14_3.9x8.7mm_P1.27mm | U2 |
| 1 | MC78M09_TO252 | Package_TO_SOT_SMD:TO-252-2 | U1 |
| 1 | PJ-037BH | DC_Jacks:CUI_PJ-037BH | J6 |
| 1 | TestPoint_2Pole | Connector_PinHeader_2.54mm:PinHeader_1x02_P2.54mm_Vertical | TP1 |
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Questions
How big is the Distribution amp PCB?
It measures 63.5 × 100 mm and has 4 copper layers, 1.6 mm thick.
What parts does the Distribution amp use?
42 parts, built around the 1N4148WS and PJ-037BH. 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 Distribution amp KiCad files?
From the thinkfat/dist-amp repository on GitHub, at the commit this page was made from: the board is distribution-amp.kicad_pcb. PCBKit opens the board in the browser, with nothing to install.
Can I use the Distribution amp design in my own project?
Its repository states no licence, so its author keeps all rights: ask thinkfat before reusing the design.