This approach assumes that every device pin would have a passive component such as a series resistor. All DUTs on the BIB will share the same bias per pin. The selection of bias per pin is done jumper selection per board. Power, GND or Signals selection is made easy for all alike pins for all devices on the Burn-in Board.
Another version of this approach is to have an option per pin to by-pass the resistor to short pins like Power and Ground direct.
- Density is impacted but not as bad as complete universal approach
- Every pin can be programmed to either power supply, GND or clock.
- This works best for products that share similar pins as power and GND.
- Every device pin can only have one type of component a resistor in this case. and its value is fixed
- Pins of the same device can not have interconnection independent of other positions on the board
- Even if a pin is No Connect, it will still have resistor in parallel with alike pins of other devices
- A program card per circuit type per board to bias the pins that are brought to the edge of the board to the correct oven contact pins. This maybe less of an issue if the number of power pins any given pin can be limited to only 2 – 3 different voltage levels. This is also less of an issue in the Rel-Inc style boards, since the type of voltage is not fixed on the oven and can be changed.
- If the option to by-pass resistors are selected, there would be jumpers per pin so density is even less since it will occupy real estate space on the board. It also would mean every time a change in the direct by-pass connection is made and operator would need to physically add or remove a jumper from the shunts assembled on each position.
NOTE: This approach can take a different form, where the resistors will not be assembled instead pin receptacles will be assembled on the board and every time a circuit change the right components have to be stuffed in. This is an operational nightmare, basically we have sockets on a burn-in board and pads to stuff resistors or capacitors. Labor and component cost would out weight the cost of dedicated boards.