Dewan Sirkuit dicitak (PCB), ogé katelah Printed Circuit Board (PCB), digunakeun pikeun nyambungkeun sareng fungsina komponén éléktronik sareng mangrupikeun bagian anu penting dina desain Sirkuit listrik. Artikel ieu bakal ngawanohkeun aturan dasar perenah PCB jeung wiring.

Ngawincik aturan dasar perenah dewan PCB jeung wiring

Basic rules of component layout

1. According to the layout of circuit modules, the related circuit to achieve the same function is called a module, the components in the circuit module should adopt the principle of nearby concentration, and the digital circuit and analog circuit should be separated;

2. Komponén, alat sareng sekrup henteu kedah dipasang dina 3.5mm (pikeun M2.5) sareng 4mm (pikeun M3) di sakitar liang anu teu dipasang sapertos liang anu nempatkeun sareng liang standar dina 1.27mm;

3. Horizontal resistance, inductor (plug-in), electrolytic capacitor and other components under the cloth hole, so as to avoid the wave soldering hole and component shell short circuit;

4. Bagian luar komponén 5mm jauh ti ujung piring;

5. Jarak antara sisi luar Pad of ningkatna unsur jeung sisi luar unsur inserting meungkeut leuwih gede ti 2mm;

6. Komponén cangkang logam jeung bagian logam (kotak shielding, jsb) teu bisa noél komponén séjén, teu bisa deukeut jeung garis dicitak, Pad, jarak kudu leuwih gede ti 2mm. The size of positioning holes, fastener mounting holes, elliptic holes and other square holes in the plate is greater than 3mm from the plate side;

7. elemen pemanasan teu kudu deukeut kawat sarta elemen termal; Alat-alat panas tinggi kudu disebarkeun merata;

8. stop kontak kakuatan kudu disusun sabudeureun dewan dicitak sajauh mungkin, sarta terminal wiring tina stop kontak kakuatan sarta busbar disambungkeun ka dinya kudu disusun dina sisi sarua. Khususna, ulah nempatkeun sockets kakuatan sarta panyambungna las séjén antara panyambungna pikeun mempermudah las of sockets sarta konektor ieu sarta rarancang jeung wiring tina kabel kakuatan. Jarak tina sockets kakuatan sarta panyambungna las kudu dianggap pikeun mempermudah panempatan sarta ngaleupaskeun colokan kakuatan;

9. Tata ruang komponén séjén:

All IC components should be aligned unilaterally, and polarity marks of polar components should be clear. Polarity marks on the same printed board should not be more than two directions. When two directions appear, the two directions should be perpendicular to each other.

10, the surface wiring should be properly dense, when the density difference is too large should be filled with mesh copper foil, the grid is greater than 8mil (or 0.2mm);

11, the patch pad can not have through holes, so as to avoid the loss of solder paste resulting in virtual welding components. garis sinyal penting teu diwenangkeun ngaliwatan suku stop kontak;

12, patch alignment sapihak, arah karakter konsisten, arah bungkusan konsisten;

13. Alat polar kudu ditandaan dina arah nu sarua sajauh mungkin dina dewan sarua.

Dua, aturan wiring komponén

1. Tarik wewengkon wiring dina wewengkon ≤1mm ti ujung dewan PCB, sarta dina 1mm sabudeureun liang ningkatna, sarta nyaram wiring;

2. Jalur kakuatan saloba mungkin, teu kudu kirang ti 18mil; lebar garis sinyal teu kudu kirang ti 12mil; CPU incoming and outgoing lines should not be less than 10mil (or 8mil); Jarak garis henteu kirang ti 10mil;

3. liang normal teu kirang ti 30mil;

4. Lebetkeun garis ganda: pad 60mil, aperture 40mil;

lalawanan 1 / 4W: 51 * 55mil (0805 lambar); Langsung sisipan pad 62mil, aperture 42mil;

Kapasitor non-polar: 51 * 55mil (0805 lambar); Langsung sisipan pad 50mil, aperture 28mil;

5. Catet yén kabel listrik sareng kabel darat kedahna radial dugi ka tiasa, sareng kabel sinyal henteu kedah digulung.

Kumaha carana ningkatkeun kamampuan anti gangguan sareng kasaluyuan éléktromagnétik?

Kumaha carana ningkatkeun kamampuan anti gangguan sareng kasaluyuan éléktromagnétik nalika ngembangkeun produk éléktronik nganggo prosésor?

1. Sababaraha sistem di handap ieu kedah nengetan husus ka gangguan anti éléktromagnétik:

(1) frékuénsi jam mikrokontroler utamana tinggi, siklus beus téh sistem utamana gancang.

(2) Sistim nu ngandung kakuatan tinggi, sirkuit nyetir-ayeuna, kayaning spark generating relay, switch arus tinggi, jsb.

(3) sistem sareng sirkuit sinyal analog lemah sareng sirkuit konversi A / D presisi tinggi.

2. Ukuran di handap ieu dilaksanakeun pikeun ningkatkeun kamampuan gangguan anti-éléktromagnétik sistem:

(1) Pilih mikrokontroler kalayan frékuénsi handap:

Mikrokontroler kalayan frékuénsi jam éksternal anu handap sacara efektif tiasa ngirangan bising sareng ningkatkeun kamampuan anti gangguan sistem. Gelombang pasagi sareng gelombang sinus sareng frékuénsi anu sami, komponén frékuénsi luhur gelombang pasagi langkung ti gelombang sinus. Sanajan amplitudo komponén frékuénsi luhur gelombang pasagi leuwih leutik batan gelombang fundamental, nu leuwih luhur frékuénsi, leuwih gampang pikeun emit sarta jadi sumber noise. Noise frekuensi tinggi anu paling boga pangaruh anu dihasilkeun ku mikrokontroler kira-kira 3 kali tina frékuénsi jam.

(2) Ngurangan distorsi dina pangiriman sinyal

Microcontrollers utamana dijieun ku téhnologi CMOS-speed tinggi. Static input current signal input at about 1 ma, around ten pf in the input capacitance, high input impedance, high speed CMOS circuit outputs are fairly on load capacity, namely the considerable output value, the output end of a door through a very long lead to the high input, the input impedance reflection problem is very serious, it will cause the signal distortion, Ningkatkeun sora sistem. Nalika Tpd “Tr”, janten masalah jalur transmisi, kudu mertimbangkeun pantulan sinyal, cocog impedansi jeung saterusna.

Waktu reureuh tina sinyal dina papan cetak pakait sareng impedansi karakteristik kalungguhan, nyaéta kana konstanta diéléktrik tina bahan papan cetak. Sinyal kasarna tiasa dianggap ngarambat antara 1/3 sareng 1/2 laju cahaya dina kalungguhan PCB. Tr (waktu tunda standar) tina elemen telepon logika anu biasa dianggo dina sistem anu diwangun ku mikrokontroler antara 3 sareng 18ns.

Dina papan sirkuit anu dicitak, sinyal ngalangkungan résistor 7W sareng kalungguhan 25cm, sareng tunda on-line sakitar 4 dugi 20ns. That is to say, the signal on the printed line lead as short as possible, the longest should not exceed 25cm. Sareng jumlah liang kedah sakedik-gancang, langkung saé henteu langkung ti 2.

Nalika waktos naékna sinyal langkung gancang tibatan waktos reureuh sinyal, éléktronika gancang diterapkeun. Dina titik ieu, patandingan impedansi tina jalur transmisi kedah dipertimbangkeun. Pikeun pangiriman sinyal antara blok terpadu dina papan sirkuit CINTA, Td Trd kudu dihindari. Langkung ageung papan sirkuit anu dicitak, langkung gancang sistemna henteu tiasa gancang teuing.