General requirements for PCB circuit board test point production_PCB circuit board|PCB circuit board|single-sided circuit board|double-layer circuit board|multi-layer circuit board|soft and hard combined circuit board--Dongguan Siho Electronics Co., Ltd.

General requirements for PCB circuit board test point production
Update：2019/1/16 17:18:14
Critical components require preset test points on the PCB board. The pads used to solder the external assembly components are not allowed to double as test points, and special test pads must be additionally preset to ensure that solder joint inspection and production debugging are all done. The pads used for testing are arranged as much as possible on the uniform side of the PCB board, and even if detected, it is beneficial to reduce the cost of the inspection.

1. Process preset requirements

(1) The test point interval PCB circuit board edge needs to be greater than 5mm;

(2) The test point shall not be covered by solder resist or text ink;

(3) The best soldering point at the test point or the metal with soft texture, easy to pass, and not easy to oxidize, to ensure that the grounding of the probe is extended and the probe application life is prolonged.

(4) The test point shall be placed 1 mm around the component to stop the probe and component from colliding;

(5) The test point should be placed in the positioning hole (for the precise positioning with the test point, the best non-metallized hole, the positioning hole error should be within ±0.05mm) and the outer circumference of 3.2mm;

(6) The diameter of the test point is not less than 0.4mm, and the spacing between adjacent test points is most fortunately less than 2.54mm, but not less than 1.27mm;

(7) The test surface cannot be placed with components with a height exceeding 6.4 mm. Excessive components will result in poor contact of the test fixture on the test point;

(8) The interval C from the middle of the test point to the edge of the chip component has the following relationship with the SMD height H: SMD height H ≤ 3 mm, C ≥ 2 mm; SMD height H ≥ 3 mm, C ≥ 4 mm.

(9) The size, spacing and layout of the test pad should also match the requirements of the test equipment used.

2. Electrical Preset Requirements (1) Try to pass the SMC/SMD test point of the component surface through the via hole to the soldering surface. The diameter of the via hole is greater than 1mm. It can be tested with a single-sided needle bed to reduce the test cost.

(2) Each electrical contact requires a test point, each IC must have power and ground test points, and as close as possible to the components, the most fortunately within 2.54mm;

(3) When setting the test point on the circuit trace, the width can be enlarged to 1mm;

(4) The test points should be evenly distributed on the PCB to reduce the stress concentration of the probe;

(5) The power supply line on the PCB circuit board should be set to test breakpoints in a sub-area, so that the power supply can be decoupled or hindered from querying. When setting a breakpoint, consider the power carrying capacity after the test breakpoint is restored.