IC test socket contact Resistance Influence factor

Influence factor of IC test socket contact Resistance 

Mainly affected by factors such as contact material, positive pressure, surface state, and voltage and current.

1) Contact material

Electrical connector technical conditions Different types of mating contacts made of different materials, different contact resistance evaluation indicators are specified. For example, GJB101-86, a general specification for small circular quick-disconnecting and environmentally-resistant electrical connectors, has a contact resistance of 1 mm diameter of the mating contact, copper alloy ≤ 5 mΩ, and ferroalloy ≤ 15 mΩ.

2) Positive pressure

The positive pressure of the contacts refers to the forces generated by the surfaces in contact with each other and perpendicular to the contact surfaces. As the positive pressure increases, the number and area of contact micro-points also gradually increase, and the contact micro-points transition from elastic deformation to plastic deformation. Since the concentrated resistance is gradually reduced, the contact resistance is lowered. The positive contact pressure is primarily dependent on the geometry and material properties of the contacts.

3) Surface state

The surface of the contact piece is a loose film formed by mechanical adhesion of dust, rosin, oil stain, etc. on the surface of the contact surface. This layer of film is easily embedded in the microscopic pits on the contact surface due to the particulate matter. The area is reduced, the contact resistance is increased, and it is extremely unstable. Second, due to the physical adsorption and chemical adsorption of the pollution film, the metal surface is mainly chemical adsorption, which is caused by electron migration after physical adsorption. Therefore, for some products with high reliability requirements, such as aerospace electrical connectors must have clean assembly production environment conditions, perfect cleaning process and necessary structural sealing measures, the use unit must have good storage and use operating environment conditions .

4) Using voltage

When the voltage is used to reach a certain threshold, the contact film layer is broken down, and the contact resistance is rapidly lowered. However, due to the thermal effect, the chemical reaction in the vicinity of the film layer is accelerated, and the film layer has a certain repairing effect. The resistance is then nonlinear. In the vicinity of the threshold voltage, small fluctuations in the voltage drop cause the current to vary within a range of twenty or ten times. A large change in contact resistance, without understanding this non-linearity, can cause errors when testing and using contacts.

5) Current

When the current exceeds a certain value, the Joule heat generated after the contact of the contact interface at a small point causes the metal to soften or melt, which affects the concentrated resistance and reduces the contact resistance.

6)Pogo pin and spring pin for IC test socket

Pogo pin is used on the IC customized socket for BGA,CQFP,LGA,SOP,SOT, and the popular package chip. This series models pogo pin have different contact resistance. Because there are any different size and thickness, that is related with the pogo pin contact resistance.

ANDK socket now have less than 50mΩ and 100mΩ pogo pin.

Spring pin is ANDK conventional socket contact pins, this pins are unique design, it can provide the spring force and about 30mΩcontact resistance.

Special design socket available, any requirements, please contact with me.