Samtec/Millmax (0.050") Headstages

PCB designs and manufacturing

Design files for a 32 channel RHD2132-based headstage using Samtec or Mill-Max 50 mil connectors can be found on the github (https://github.com/open-ephys/headstage/tree/master/samtec). These headstages are designed so that the connector can soldered to the end of the PCB (avoiding the use of a surface mount 50 mil connector). Thus, the PCBs should be manufactured using slightly thinner than usual circuit board (~0.8 mm). A recommended manufacturer is the Fusion PCB service (http://www.seeedstudio.com/depot/fusion-pcb-service-2-layers-p-835.html), which can provide 10 PCBs for ~$2/ea. (Extra headstage PCBs may also be available from other users.)

PCB assembly

The accelerometer, Intan RHD2132, and Omnetics connector should be soldered first. A solder mask stencil ($9 from http://www.oshstencils.com/) can be used to precisely locate solder paste, or it can be carefully applied with a fine tip. If a PCB oven is not available, a heat gun can be employed to reflow solder paste with satisfactory results. If using a heat gun, however, care must be taken not to damage the integrated circuits. Best practice is to observe the solder joints through a microscope while applying heat. The remaining components  (11 small (0603 or 0402) surface mount resistors, capacitors, and an LED) can then be soldered on by hand. Finally, the Samtec or Mill-Max connector can be soldered into place. A completed headstage is shown below. Note that after testing, the physical interface between PCB and Omnetics connector should be reinforced with epoxy.