Rigid Flex Architecture against Two Boards and a Connector
Rigid-flex architecture eliminates discrete connector failures and signal discontinuities while reducing assembly labor, justifying higher bare-board costs.
Board to Board Connector Parasitics
Parasitic Characteristic
Unintended electrical behaviors define the signal integrity limits of high-speed interconnects between joined substrates. Board to board connector parasitics represent the stray capacitance and inductance inherent in the physical geometry of mated pins and plastic housings. These attributes limit bandwidth by introducing impedance discontinuities and crosstalk at the interface where two sub-assemblies meet.
Practitioners quantify these effects through S-parameter models provided by manufacturers to ensure that high-frequency data streams remain within jitter and loss budgets.
Propagation Delay
Signal speed through a connector remains lower than through a standard copper trace because of the dielectric constant of the connector body and the physical length of the metal pins. Every board to board connector parasitics instance contributes a measurable delay that affects timing margins in synchronous interfaces. Total path length increases as pins extend through the connector body and reach the opposing receptacle.
Compensation Methodology
Careful pad design at the landing site helps mitigate the reactive elements of the connection. Reducing the size of the solder pads or using specific via-in-pad geometries can offset the excess capacitance introduced by the connector pins. Surface mount pads often require a relief in the reference plane underneath them to maintain the target characteristic impedance.
Effective board to board connector parasitics management requires verifying the stackup against the connector footprint before fabrication. Simulation software identifies the precise dimensions needed to counteract the inductance of the pin transition. Signal transitions through the connector body depend on this layout to avoid reflections.