Listrik statis tina awak manusa, lingkungan komo di jero alat éléktronik tiasa nyababkeun sababaraha ruksakna chip semikonduktor presisi, sapertos nembus lapisan insulasi ipis dina komponén; Ruksakna gerbang komponén MOSFET sareng CMOS; Trigger lock in CMOS device; Short-circuit reverse bias PN junction; Jalan pondok-circuit positip bias PN simpang; Lebur kawat las atanapi kawat aluminium di jero alat aktip. In order to eliminate the interference and damage of electrostatic discharge (ESD) to electronic equipment, it is necessary to take a variety of technical measures to prevent.

salila Dewan PCB rarancang, résistansi ESD tina PCB tiasa diwujudkeun ngalangkungan lapisan, perenah anu pas sareng instalasi. Salami prosés desain, kaseueuran parobihan desain tiasa diwatesan pikeun nambihan atanapi ngaleungitkeun komponén ngalangkungan prediksi. Ku nyaluyukeun perenah PCB sareng kabel, ESD tiasa dicegah kalayan saé. Here are some common precautions.

How to realize ESD resistance design of PCB

1. Use multi-layer PCB as far as possible. Compared with double-sided PCB, the ground plane and power plane, as well as the close spacing between signal wire and ground wire can reduce the common-mode impedance and inductive coupling, and make it reach 1/10 to 1/100 of the double-sided PCB. Try to place each signal layer close to a power or ground layer. For high-density PCBS with components on both the top and bottom surfaces, very short connections, and lots of ground filling, consider using inner lines.

2. Pikeun PCB dua sisi, catu daya antar-jaringan anu ketat sareng jaringan taneuh kedah dianggo. Ari kakuatanna aya di gigireun taneuh sareng kedah disambungkeun sabisa antara garis nangtung sareng horizontal atanapi zona eusian. The grid size of one side shall be less than or equal to 60mm, or less than 13mm if possible.

3. Pastikeun yén unggal sirkuit sakumaha kompak mungkin.

4. Pasang sadayana panyambungna sabisa-bisa.

5. Upami tiasa, pimpin kabel listrik ti tengah kartu jauh ti daérah anu rentan akibat karusakan ESD langsung.

6, dina sadaya lapisan PCB di handapeun konektor anu ngarah kaluar tina kasus (gampang langsung pencét ku ESD), tempatkeun chassis atanapi ground polygon anu lega, teras sambungkeun sareng liang dina interval sakitar 13mm.

7. Place mounting holes on the edge of the card, and the top and bottom pads of open flux are connected to the ground of the chassis around the mounting holes.

8, PCB assembly, do not apply any solder on the top or bottom pad. Use screws with built-in washers to provide tight contact between PCB and metal chassis/shield or support on ground surface.

9, dina unggal lapisan antara chassis sareng ground circuit, pikeun nyetél “zona isolasi” anu sami; Upami tiasa, jaga jarakna dina 0.64mm.

10, in the top and bottom of the card near the installation hole position, every 100mm along the chassis ground and circuit ground with 1.27mm wide line together. Adjacent to these connection points, a pad or mounting hole for installation is placed between the chassis ground and the circuit ground. These ground connections can be cut with a blade to remain open, or jump with magnetic beads/high frequency capacitors.

11, if the circuit board will not be put into the metal box or shielding device, the top and bottom of the circuit board chassis ground wire can not be coated with solder resistance, so that they can be used as ESD arc put electrode.

12. Set a ring around the circuit in the following manner:

(1) In addition to the edge connector and chassis, the entire periphery of the ring access.

(2) Pastikeun yén lébar sadaya lapisan langkung ageung tibatan 2.5mm.

(3) liang-liangna nyambung dina ring unggal 13mm.

(4) Sambungkeun taneuh annular sareng taneuh umum tina sirkuit multi-lapisan babarengan.

(5) For double panels installed in metal cases or shielding devices, the ring ground shall be connected to the common ground of the circuit. Sirkuit dua sisi anu teu dijagaan kedah dihubungkeun sareng ground ring, ground ring henteu kedah dilapis ku fluks, supados ground ring tiasa janten rod debit ESD, sahenteuna gap lebar 0.5mm dina ground ring (sadayana lapisan), sahingga loop anu ageung tiasa dihindari. Kabel sinyal kedah henteu kirang ti 0.5mm jauh tina taneuh ring.

Di daérah anu tiasa langsung pencét ku ESD, kawat taneuh kedah diteundeun caket unggal garis sinyal.

14. The I/O circuit should be as close to the corresponding connector as possible.

15. The circuit susceptible to ESD should be placed near the center of the circuit, so that other circuits can provide a certain shielding effect for them.

16, biasana disimpen dina résistor séri sareng manik magnét dina tungtung panarima, sareng pikeun supir kabel anu rentan ka ESD, ogé tiasa nimbangkeun nempatkeun résistor séri atanapi manik magnét dina tungtung supir.

17. Protéksi samentawis biasana disimpen dina tungtung panarima. Anggo kabel kandel pondok (kirang tina 5x lébar, langkung saé kirang ti 3x lébar) pikeun nyambung ka lantai chassis. Sinyal sareng garis taneuh tina konektor kedahna langsung nyambung kana panyalindungan samentawis sateuacan sésa sirkuit tiasa nyambung.

18. Tempatkeun kapasitor saringan dina konektor atanapi dina 25mm tina sirkuit panarima.

(1) Anggo kawat pondok sareng kandel pikeun nyambungkeun sasis atanapi sirkuit panampi (panjangna kirang ti 5 kali lébar, langkung saé kirang ti 3 kali lébar).

(2) Garis sinyal sareng kawat taneuh mimiti disambungkeun kana kapasitor teras disambungkeun kana sirkuit panarima.

19. Pastikeun garis sinyalna pondok-gancang.

20. Nalika panjang kabel sinyal langkung ageung tibatan 300mm, kabel ground kedah diteundeun sajajar.

21. Pastikeun yén area loop antara garis sinyal sareng loop anu pakait sakedik mungkin. Pikeun garis sinyal anu panjang, posisi garis sinyal sareng garis dasar kedah dirobih unggal sababaraha séntiméter pikeun ngirangan daérah gelung.

22. Sinyal drive ti tengah jaringan kana sababaraha sirkuit narima.

23. Ensure that the loop area between the power supply and the ground is as small as possible. Place a high frequency capacitor near each power pin of the IC chip.

24. Tempatkeun kapasitor bypass frékuénsi luhur dina 80mm unggal konektor.

25. Where possible, fill the unused areas with land, connecting all layers of fill at 60mm intervals.

26. Pastikeun yén taneuh dihubungkeun sareng dua ujung anu berlawanan tina daérah ngeusian taneuh ageung (sakitar langkung ageung tibatan 25mm * 6mm).

27. Nalika panjang bukaan dina catu daya atanapi pesawat darat ngaleuwihan 8mm, sambungkeun dua sisi lawang ku garis sempit.

28. Garis ulang, garis sinyal ngaganggu atanapi garis sinyal pemicu tepi teu kedah ditempatkeun caket kana ujung PCB.

29. Sambungkeun liang pemasangan sareng circuit ground biasa, atanapi ngasingkeunana.

(1) Nalika bracket logam kedah dianggo sareng alat taméng logam atanapi chassis, résistansi nol ohm kedah dianggo pikeun ngawujudkeun hubunganana.

(2) nangtoskeun ukuran liang ningkatna pikeun ngahontal pamasangan logam atanapi palastik pangrojong anu dipercaya, dina luhur sareng handapeun liang ningkatna pikeun ngagunakeun pad anu ageung, alas handap henteu tiasa nganggo résistansi fluks, sareng mastikeun yén handapeun Pad henteu nganggo prosés las gelombang pikeun las.

30. Kabel sinyal anu dijaga sareng kabel sinyal anu teu dijaga teu tiasa diatur sacara paralel.

Perhatian khusus kedah dibayar ka kabel sinyal ngareset, ngaganggu sareng ngendalikeun garis sinyal.

(1) Nyaring frékuénsi luhur kedah dianggo.

(2) Jauhan sirkuit input sareng output.

(3) Jauhkeun tina ujung papan sirkuit.

32, PCB kedah dilebetkeun kana chassis, ulah dipasang dina posisi muka atanapi sendi internal.

Nengetan kabel garis sinyal handapeun manik magnét, antara bantalan sareng tiasa ngahubungi manik magnét. Sababaraha manik ngalaksanakeun listrik sacara lumayan sareng tiasa ngahasilkeun jalur konduktif anu teu disangka-sangka.

Upami hiji pasualan atanapi motherboard pikeun masang sababaraha circuit board, kedahna anu paling peka kana sirkuit listrik statis di tengahna.