Anyone measuring small resistances or high currents cannot avoid four-wire measurement: only when the current path and the sense path are separated does the contact resistance stay out of the result. The difficulty is space – two separate contact points have to fit onto a single solder ball.
That is exactly what our patented Kelvin contact is designed for. Its bevelled head places two contact points just 0.125 mm apart onto a single BGA ball on the device side. On the test system side, the contact transitions to a convenient 0.5 mm pitch, so the load board can be routed with reasonable effort.
Technical features
- Kelvin contact spacing on the device side: 0.125 mm
- Pitch on the test system side: 0.5 mm
- Angular offset: less than 1°
- Service life: specified for at least 500,000 cycles
- Contact material: steel alloy, around 300 % harder than gold-plated copper beryllium
- Self-cleaning contact head, spring-mounted, wide tolerance window for device centring
- Suitable for BGA, QFN, QFP and WLCSP
The spring mounting also simplifies assembly: the contact compensates for tolerances itself instead of passing them on to the device.
