Multiple wire filaments connect the solder ball and circuit board pad. What is the minimum number of wires needed to have contact resistance of <50 mOhms?
4 to 9 wires depending on the ball pitch.
|Ball pitch (mm)||Ball diameter (mm)||Ball height (mm)||Wire pitch (mm)||# of contacting wire per ball||Total current carrying capacity (mA)|
|1.27||0.6 – 0.9||0.5 – 0.7||0.1||9 – 16||450 – 800|
|1.0||0.5 – 0.7||0.4 – 0.6||0.1||9 – 16||450 – 800|
|0.8||0.3 – 0.5||0.2 – 0.3||0.1||4 – 9||200 – 450|
|0.5||0.25 – 0.35||0.15 – 0.25||0.05||4 – 9||200 – 450|
|0.4||0.2 – 0.3||0.12 – 0.18||0.05||4 – 9||200 – 450|
Yes, the solder mask prevents shorting with traces.X
The mounting screws should be torqued using the supplied hex key until they are finger tight.X
The elastomer needs to be cleaned every 200 cycles.X
In order to avoid target board flexing under compression force, a custom insulation plate will be necessary. The choice between custom insulation plate and backing plate depends on the amount of compression force required.X
A. By applying recommended torque using torque driver or
B. By turning the compression screw using the hex key by 1/2 to 3/4 of a turn after the compression screw touches the compression plate.
When the die size is smaller than the chip size and outer rows of BGA don’t have direct compression from the compression plate, the IC frame will help to fill the gap and put force evenly on outer rows. The substrate thickness and the number of rows outside the die area are the critical factors in deciding the need for IC frame.X
Elastomer becomes soft and does not return back to its original state.X