DEMO — fictional range. Local brief only, NOT SENT. No personal data is collected or transmitted.
SIGNAL
At board level the connection is part of the circuit.
A board connector is not only a mechanical joint. Its pitch, its impedance and its return path decide whether the signal survives it.
- Current per contact
- And how many carry current at once, because the assembly runs hotter
- Contact resistance
- Low and stable, which is a property of the force and the plating
- Impedance
- For high-speed signals, set by the pitch and the ground arrangement
- Return path
- Which contacts carry the return, because a signal without one is a loop
- Crosstalk
- Decided by the spacing and by how many returns sit between signals
- Sequencing
- Which contacts mate first, so power and ground make before signal
Illustrative signal record
| Property | Set by | What it changes |
|---|---|---|
| Resistance | Force and plating | Heat at the contact, and the voltage seen by the load |
| Impedance | Pitch and ground arrangement | Whether a high-speed signal reflects |
| Crosstalk | Spacing and returns | Whether adjacent signals interfere |
| Sequencing | Contact length | Whether ground makes before power, at the pin rather than the drawing |
Why the return path is a connector decision.
Because a signal needs a return, and at the connector the return is whatever contacts the designer assigned to it. A connector with one ground for twenty signals makes every signal a loop with the same return.
The question worth asking instead.
How many returns there are per signal, and which contacts mate first. A supplier who can answer that has thought about the interface rather than the part.