A kind of test point adding method of high-speed-differential cablingTechnical field
The invention belongs to server board testing field, and in particular to a kind of test point addition side of high-speed-differential cablingMethod.
Background technology
ICT, is in circuit tester abbreviation, In-circiut tester.
Pad, pad.
With the high speed development of electronics technology, I/O interface function is intended to the high densification direction hair of high speed on server master boardExhibition, the lifting of signal rate, the diminution of pcb board card structure area and the complexity lifting of plate level signal interconnection etc. all can be to heightFast signal transmission quality has an impact.Thus, the personnel of designing and developing will utilize signal integrity theoretical, select electrical property betterSheet material reduce signal transmission attenuation, or designed using homogeneous stack to reduce between each high speed cabling of same interlayer wiringCoupling crosstalk, or by reducing the resistance between PCB and connector and bga chip to pcb board impedance value optimum choiceIt is anti-discontinuous, it is used for lifting signal quality of the high speed signal in complicated link transmission with upper type.
Then, when board PCB is produced, each short open circuit production abnormal problem of board is controllable when being produced in batches for guaranteeProperty, the fraction defective of board is reduced, generally in the board design phase, ICT test designs is imported, i.e., increase on pcb board card and surveyPilot, usually require that it tests dot coverage more than 90%, thus, it can all increase survey on nearly all high speed cabling on mainboardPilot.
Influence of the geomery of test point to high speed cabling is considered in increase test point, typically with low speed cablingIncrease a diameter of 30mil circular Pad as test point, and high speed cabling is increased as routing line width, length is20mil test rectangle pad is as test point, so test spot size is similar with high speed cabling on high speed cabling, such as Fig. 1 institutesShow.The rectangular pads pad similar to high speed cabling is relatively small as transmission loss influence of the test point on high speed cabling, soIn the exploitation of high speed board, when especially requiring stricter to high-speed transmission line loss, such a test point addition manner is often extensiveUse.
But when carrying out test point addition using prior art, the test spot size on high speed cabling is smaller, surveysProbe header is not easy to contact with test point, increases difficulty of test, when pcb board card volume production is tested, brings testing time increaseAnd the risk of testing expense lifting.
This is the deficiencies in the prior art, therefore, for drawbacks described above of the prior art, there is provided a kind of high-speed-differential cablingTest point adding method, be necessary.
The content of the invention
It is an object of the present invention to for test point adding method on above-mentioned existing high speed cabling test probe is not easyThe defects of being contacted with test point, there is provided a kind of test point adding method of high-speed-differential cabling, to solve above-mentioned technical problem.
To achieve the above object, the present invention provides following technical scheme：
A kind of test point adding method of high-speed-differential cabling, comprises the following steps：
Step 1. adds circular pad pad as test point on every high-speed-differential cabling；
Step 2. digs copper foil on the adjacent earth formations GND of circular pad pad test points, and the size for digging copper foil is along circular padPad edges stretch out the circular size formed after setpoint distance.
Further, also comprise the following steps after step 2：
Step 3. analog simulation checking addition circular pad pad test points and the adjacent earth formations GND in circular pad pad test pointsThe upper influence for digging copper foil to high-speed-differential cabling transmission loss.
Specifically, before and after contrast addition circular pad pad test points, the transmission loss on high-speed-differential cabling；
Contrast is dug before and after copper foil on the adjacent earth formations GND of circular pad pad test points, the transmission damage on high-speed-differential cablingConsumption；
It is circular with being added on high-speed-differential cabling after contrast digs copper foil on the adjacent earth formations GND of circular pad pad test pointsBefore pad pad test points, the transmission loss on high-speed-differential cabling.
Further, 30mil circular pads pad is added in step 1 on every high-speed-differential cabling as test point.
Further, the setpoint distance in step 2 is 3mil.
Further, circular pad pad test points are symmetrically added in step 1 on every high-speed-differential cabling.
Further, two difference cablings are parallel to each other in step 1, and circular pad pad test points are centrally disposed in differenceDivide on the outside of cabling.
Further, two difference cablings are provided with the reserved location of circular pad pad test points, circle weldering in step 1Disk pad test points are arranged on reserved location.
Further, the reserved location on two difference cablings is oppositely arranged, circular pad pad test points it is centrally disposedOn difference cabling.
Further, the reserved location on two difference cablings is staggered, circular pad pad test points it is centrally disposedOn difference cabling.
Further, circular pad pad test points are centrally disposed in that to leave the difference cabling of reserved location for it relativeDifference cabling on.
The beneficial effects of the present invention are：
The present invention uses circular pad pad test points, increases the contact area of test probe and high-speed-differential cabling, not only dropsThe low difficulty of production test, also reduces the expense of production test, improves the ageing of later stage board production test；TogetherWhen, copper foil is dug on the adjacent earth formations GND of circular pad pad test points, simple increase test point is reduced and high-speed-differential is walkedThe influence of line transmission loss.
In addition, design principle of the present invention is reliable, and it is simple in construction, there is very extensive application prospect.
As can be seen here, the present invention is compared with prior art, with prominent substantive distinguishing features and significantly progressive, its implementationBeneficial effect be also obvious.
Brief description of the drawings
Fig. 1 is the schematic diagram of test point of the increase as feature sizes on high-speed-differential cabling in the prior art；
Fig. 2 is flow chart of the method for the present invention；
Fig. 3 is that circular pad pad test point schematic diagrames are added in embodiment 1；
Fig. 4 is that circular pad pad test points schematic diagram 1 is added in embodiment 2；
Fig. 5 is that circular pad pad test points schematic diagram 2 is added in embodiment 2；
Fig. 6 is that circular pad pad test point schematic diagrames are added in embodiment 3；
Fig. 7 is the schematic diagram 1 that copper foil is dug on the adjacent earth formations GND of circular pad pad test points；
Fig. 8 is the schematic diagram 2 that copper foil is dug on the adjacent earth formations GND of circular pad pad test points；
Fig. 9 is before and after embodiment 1, embodiment 2 and embodiment 3 add circular pad pad test points, is believed in the high speed of different frequencyUnder number, the transmission loss on high-speed-differential cabling；
Figure 10 be embodiment 1 add before circular pad pad test points with the adjacent earth formations GND in circular pad pad test pointsIt is upper dig different size copper foils after, the transmission loss schematic diagram on high-speed-differential cabling；
Figure 11 be embodiment 1 under 10GHZ high speed signal frequency, dug on the adjacent earth formations GND of circular pad pad test pointsAfter different size copper foils, the transmission loss schematic diagram on high-speed-differential cabling；
Figure 12 be embodiment 2 add before circular pad pad test points with the adjacent earth formations GND in circular pad pad test pointsIt is upper dig different size copper foils after, the transmission loss schematic diagram on high-speed-differential cabling；
Figure 13 be embodiment 2 under 10GHZ high speed signal frequency, dug on the adjacent earth formations GND of circular pad pad test pointsAfter different size copper foils, the transmission loss schematic diagram on high-speed-differential cabling；
Figure 14 be embodiment 3 add before circular pad pad test points with the adjacent earth formations GND in circular pad pad test pointsIt is upper dig different size copper foils after, the transmission loss schematic diagram on high-speed-differential cabling；
Figure 15 be embodiment 3 under 10GHZ high speed signal frequency, dug on the adjacent earth formations GND of circular pad pad test pointsAfter different size copper foils, the transmission loss schematic diagram on high-speed-differential cabling.
Embodiment：
To enable the purpose of the present invention, feature, advantage more obvious and understandable, it is embodied below in conjunction with the present inventionAccompanying drawing in example, the technical scheme in the present invention is clearly and completely described.
As shown in Fig. 2 the present invention provides a kind of test point adding method of high-speed-differential cabling, comprise the following steps：
Step 1. adds circular pad pad as test point on every high-speed-differential cabling；On every high-speed-differential cabling30mil circular pad pad is added as test point；
Step 2. digs copper foil on the adjacent earth formations GND of circular pad pad test points, as shown in Figure 7 and Figure 8, digs the chi of copper foilVery little is the circular size formed after stretching out setpoint distance along circular pad pad edges；Setpoint distance is 3mil；
Step 3. analog simulation checking addition circular pad pad test points and the adjacent earth formations GND in circular pad pad test pointsThe upper influence for digging copper foil to high-speed-differential cabling transmission loss；
Specifically, before and after contrast addition circular pad pad test points, the transmission loss on high-speed-differential cabling；
Contrast is dug before and after copper foil on the adjacent earth formations GND of circular pad pad test points, the transmission damage on high-speed-differential cablingConsumption；
Contrast is dug after copper foil on the adjacent earth formations GND of circular pad pad test points with adding circle on high-speed-differential cablingBefore pad pad test points, the transmission loss on high-speed-differential cabling.
In above-described embodiment, 30mil circular pad pad test points are symmetrically added on every high-speed-differential cabling；
Embodiment 1 as shown in figure 3, two difference cablings are parallel to each other, walk by the difference that is centrally disposed in of circular pad pad test pointsOn the outside of line；
As shown in Figure 4 and Figure 5, two difference cablings are provided with the reserved location of circular pad pad test points to embodiment 2, circularPad pad test points are arranged on reserved location；Reserved location on two difference cablings is oppositely arranged, circular pad pad testsPoint is centrally disposed on difference cabling；
Embodiment 3 is as shown in fig. 6, two difference cablings are provided with the reserved location of circular pad pad test points, circular padPad test points are arranged on reserved location；Reserved location on two difference cablings is staggered, circular pad pad test pointsIt is centrally disposed in and is left for it on the relative difference cabling of the difference cabling of reserved location；
Analog simulation checking adds circular pad pad test points and digs copper on the adjacent earth formations GND of circular pad pad test pointsInfluence of the paper tinsel to high-speed-differential cabling transmission loss；
Specifically, as shown in figure 9, before and after contrast addition circular pad pad test points, the transmission loss on high-speed-differential cabling；Under 10GHZ high speed signal frequency, transmission line loss is before addition test point on high-speed-differential cabling in embodiment 11.06dB, transmission line loss is 2.23dB after 30mil circular pad pad test points are added on high-speed-differential cabling；Under 10GHZ high speed signal frequency, transmission line loss is before addition test point on high-speed-differential cabling in embodiment 20.97dB, transmission line loss is 1.97dB after 30mil circular pad pad test points are added on high-speed-differential cabling；Under 10GHZ high speed signal frequency, transmission line loss is before addition test point on high-speed-differential cabling in embodiment 30.95dB, transmission line loss is 1.76dB after 30mil circular pad pad test points are added on high-speed-differential cabling；
Contrast is dug before and after copper foil on the adjacent earth formations GND of circular pad pad test points, the transmission damage on high-speed-differential cablingConsumption；
It is circular with being added on high-speed-differential cabling after contrast digs copper foil on the adjacent earth formations GND of circular pad pad test pointsBefore pad pad test points, the transmission loss on high-speed-differential cabling；
As shown in Figure 10 and Figure 11, add and survey on high-speed-differential cabling under 10GHZ high speed signal frequency, in embodiment 1Transmission loss before pilot is 1.06dB, after adding 30mil circular pads on high-speed-differential cabling, in circular pad padThe transmission loss dug on the adjacent earth formations GND of test point after different size copper foils, the size for digging copper foil is circular pad pad chiWhen very little, the transmission loss on high-speed-differential cabling is 1.51dB；The size for digging copper foil is inwardly to prolong along circular pad pad edgesStretch the circular size formed after 3mil, the transmission loss on high-speed-differential cabling is 1.65dB, the size for digging copper foil be alongCircular pad pad edges stretch out the circular size formed after 1.5mil, and the transmission loss on high-speed-differential cabling isAfter 1.29dB, the 2.5mil that stretches out, transmission loss is 1.25 dB, and stretch out 3mil, 3.5mil, 4mil, 5mil, 6mil,When 6.5mil, 7mil, 8mil, 9mil, respectively corresponding to transmission loss be 1.22dB, 1.25dB, 1.26dB, 1.26dB,1.43dB, 4.77dB, 4.87dB, 5.16dB, 5.58dB；
As shown in Figure 12 and Figure 13, add and survey on high-speed-differential cabling under 10GHZ high speed signal frequency, in embodiment 2Transmission loss before pilot is 0.97dB, after adding 30mil circular pads on high-speed-differential cabling, in circular pad padThe transmission loss dug on the adjacent earth formations GND of test point after different size copper foils, the size for digging copper foil is circular pad pad chiWhen very little, the transmission loss on high-speed-differential cabling is 1.20 dB；The size for digging copper foil is inside along circular pad pad edgesThe circular size that is formed after extension 3mil, the transmission loss on high-speed-differential cabling is 1.47dB, and the size for digging copper foil is edgeCircular pad pad edges to stretch out the circular size formed after 1.5mil, the transmission loss on high-speed-differential cabling isAfter 1.10 dB, the 2.5mil that stretches out, transmission loss 1.07dB, stretch out 3mil, 3.5mil, 4mil, 5mil, 6mil,When 6.5mil, 7mil, 8mil, 9mil, respectively corresponding to transmission loss be 1.06dB, 1.06 dB, 1.12dB, 1.13dB,1.21dB, 3.49dB, 3.54dB, 3.99dB, 4.12dB；
As shown in Figure 14 and Figure 15, add and survey on high-speed-differential cabling under 10GHZ high speed signal frequency, in embodiment 3Transmission loss before pilot is 0.95dB, after adding 30mil circular pads on high-speed-differential cabling, in circular pad padThe transmission loss dug on the adjacent earth formations GND of test point after different size copper foils, the size for digging copper foil is circular pad pad chiWhen very little, the transmission loss on high-speed-differential cabling is 1.11dB；The size for digging copper foil is inwardly to prolong along circular pad pad edgesStretch the circular size formed after 3mil, the transmission loss on high-speed-differential cabling is 1.34dB, the size for digging copper foil be alongCircular pad pad edges stretch out the circular size formed after 1.5mil, and the transmission loss on high-speed-differential cabling isAfter 1.05dB, the 2.5mil that stretches out, transmission loss 1.03dB, stretch out 3mil, 3.5mil, 4mil, 5mil, 6mil,When 6.5mil, 7mil, 8mil, 9mil, respectively corresponding to transmission loss be 1.02dB, 1.04dB, 1.05dB, 1.06dB,1.12dB, 1.13dB, 1.17dB, 1.24dB, 1.29dB.
To sum up, the reserved location of circular pad pad test points is set using mode in embodiment 3 on high-speed-differential cablingTransmission loss influence it is smaller than embodiment 1 and embodiment 3；Copper foil chi is dug on the adjacent earth formations GND of circular pad pad test pointsIt is very little be along circular pad pad edges stretch out 3mil when, the transmission loss rejection ability of high-speed-differential cabling is best.
Embodiments of the invention are illustrative and not restrictive, and above-described embodiment is only to aid in understanding the present invention, becauseThis is every by those skilled in the art's technique according to the invention the invention is not restricted to the embodiment described in embodimentOther embodiments that scheme is drawn, also belong to the scope of protection of the invention.