PCB in-circuit test technology production and reliable test requirements

1. The ICT test PCBA at least in the PCB diagonal design of two non-metallized holes for positioning holes. Positioning hole diameter can specify a size, such as 3.00 + 0.08/0mm. positioning holes from the edge of the distance has no special requirements, leaving more than 1.50mm effective distance can be.wafer tester Recommended according to the center of the hole from the edge of 5.00mm above the distance design. 2.

2 in-line test point refers to the contact part of the probe test, there are mainly three kinds: ① from the circuit network specifically led to the process pad or metallization through-hole; ② open the solder layer of tin through-hole; ③ through-hole insertion device solder joints. 3 in-line test point setup requirements: ① the circuit network or metallization through-hole; ② open the solder layer of tin through-hole; ③ through-hole plug device solder joints.

3. Test point setup requirements: ① If a node network has a node that is connected to a cartridge device,wafer probe testing then there is no need to set up a test point. ② If all the components connected in a node network are boundary-scan devices (i.e., digital devices), then this network does not need to design test points. ③ Except for the above two cases, every wiring network should have a test point, at least one test point for every 2A of current on the single board power and ground alignments. Test points as far as possible to concentrate on the welding surface, and the requirement of uniform distribution on the single board.

4. test point size requirements: test pads or used as a test hole hole plate, the minimum pad diameter (refers to the outside diameter of the hole plate) should be greater than or equal to 0.90mm, recommended 1.00mm. adjacent test points should be greater than or equal to the center of the distance between 1.27mm, 1.80mm recommended.

5. test points and soldermask covered by the minimum interval of 0.20mm, recommended 0.30mm. 6. test points and device pads.

6. The minimum interval between the test point and the device pad is 0.38mm, recommended 1.00mm.

7. If the height of the component package body is less than or equal to 1.27mm, the distance between the test point and the device body should be greater than or equal to 0.38mm, recommended 0.76mm; if the height of the component package body is within the range of 1.27~6.35mm, the distance between the test point and the device body should be greater than or equal to 0.76mm, recommended 1.00mm; if the height of the component exceeds 6.35mm,vibration isolation table the distance should be greater than or equal to 4.00mm, recommended 5.00mm. 8.

8. The distance between the test point and the copper foil conductor without soldermask should be 0.20mm, 0.38mm is recommended.

9. The distance between the test point and the locating hole should be more than or equal to 4.50mm.

PCB diagonal design test points test point

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