4.3 PCB Layout Recommendations

The layout for the flex PCB patch was done on a two-layer board, with the intention of maximizing overall board flexibility. Higher numbers of layers will likely limit the bending radius of the board and affect wearer comfort. For general recommendations for flex PCBs, designers should consult with the desired manufacturer of their flex board. These boards are extremely thin, therefore they can be sensitive to heat applied during the process of soldering or reflow. It is important that this aspect be considered to minimize potential damage to the board traces. If reliability is a concern, consider applying a semi-rigid design form factor by applying a stiffener to portions of the board not intended to bend. This design uses a stiffener on the front side of the board, opposite of the TMP117 in order to lengthen the life-span of the vias surrounding the sensor