Haeba mehleng ena e bohlale, tšimong ena, o batla ho ba le tsebo ho FPGA, lefats’e le tla u lahla, The Times e tla u lahla.

Ho nahanoa ka sistimi e lebelo haholo PCB design related to serdes applications are as follows:

(1) Wiring ea Microstrip le Stripline.

Lithapo tsa Microstrip li hokahane ka holim’a karolo e kantle ea lets’oao la sefofane sa litšupiso (GND kapa Vcc) se arohantsoeng ke media media ho fokotsa ho lieha; Mehala ea lente e tsamaisoa karolong e kahare ea lets’oao lipakeng tsa lifofane tse peli tsa litšupiso (GND kapa Vcc) bakeng sa ts’ebetso e kholo ea capacitive, taolo e bonolo ea impedance le lets’oao le hloekileng, joalo ka ha ho bonts’itsoe setšoantšong.

Mohala oa Microstrip le mola oa likhoele li molemo ka ho fetisisa bakeng sa wiring

(2) wiring ea lebelo le fapaneng haholo.

Mekhoa e tloahelehileng ea wiring bakeng sa lipontšo tse fapaneng tsa lebelo le phahameng e kenyelletsa Edge Coupled microstrip (top layer), Edge Coupled ribbon line (e kentsoeng leqhubu la lets’oao, e loketseng lipontšo tse fapaneng tsa li-SERDES) le Broadside Coupled microstrip, joalo ka ha ho bonts’itsoe setšoantšong.

Wiring e tsamaisang lebelo le phahameng haholo

(3) ho feta capacitance (BypassCapacitor).

Bypass capacitor ke capacitor e nyane e nang le li-impedance tse tlase haholo, tse sebelisoang haholo ho sefa tšitiso e phahameng ea maqhubu ka lipontšo tsa phetoho e phahameng. Ho na le mefuta e meraro ea li-capacitor tse fetang tse sebelisoang haholo tsamaisong ea FPGA: sistimi e nang le lebelo le holimo (100MHz ~ 1GHz) e sebelisoang haholo ke li-capacitor tse tlohang ho 0.01nF ho isa ho 10nF, eo hangata e ajoang ka hare ho 1cm ho tloha Vcc; Sistimi ea lebelo le mahareng (e fetang MHZ 100MHz e fetang leshome), sebaka se tloaelehileng sa bypass capacitor ke 47nF ho 100nF tantalum capacitor, ka kakaretso kahare ho 3cm ea Vcc; Sistimi e nang le lebelo le tlase (e ka tlase ho 10 MHZ), mofuta o sebelisoang hangata oa bypass capacitor ke 470nF ho 3300nF capacitor, sebopeho sa PCB ha se na mahala.

(4) Capacitance wiring e nepahetseng.

Capacitor wiring can follow the following design guidelines, as shown.

Wiring e sebetsang hantle

Lisebelisoa tsa pin tse nang le bokhoni li hokahane ho sebelisa boholo bo boholo ka masoba (Via) ho fokotsa coupling reactance.

Use a short, wide wire to connect the pad of the capacitor pin to the hole, or directly connect the pad of the capacitor pin to the hole.

LESR capacitors (Low Effective Series Resistance) were used.

Pini kapa lesoba le leng le le leng la GND le lokela ho hokahanngoa le sefofane se fatše.

(5) Lintlha tsa bohlokoa tsa wiring ea sistimi e phahameng haholo.

Qoba ho bilikisa ka zigzag le ho tsamaisa lioache ka kotloloho kamoo ho ka khonehang.

Leka ho tsamaisa ka lera le le leng.

Se ke oa sebelisa likoti ka hohle kamoo ho ka khonehang, hobane masoba a phunyeletsang a tla hlahisa ponaletso e matla le liphoso tsa impedance.

Sebelisa likhoele tsa microstrip karolong e kaholimo ka hohle kamoo ho ka khonehang ho qoba ts’ebeliso ea masoba le ho fokotsa ho lieha ha lets’oao.

Beha sefofane sa fatše pela leqhubu la lets’oao la oache ka hohle kamoo ho ka khonehang ho fokotsa lerata le crosstalk. Haeba ho sebelisoa lera la kahare la lets’oao, lera la lets’oao la nako le ka beoa pakeng tsa lifofane tse peli tsa lefats’e ho fokotsa lerata le tšitiso. Khutsufatsa ho lieha ha letšoao.

Letšoao la oache le lokela ho tsamaisoa hantle ka nepo.

(6) Litaba tse hlokang ho tsotelloa ka sistimi e tsamaeang ka lebelo le phahameng le ho kopanya.

Note the impedance matching of the differential signal.

Hlokomela bophara ba mola oa phapang e le hore e ka mamella 20% ea nako ea ho phahama ha lets’oao kapa ea ho oa.

Ka lihokelo tse nepahetseng, maqhubu a lekantsoeng a sehokedi a lokela ho kopana le maqhubu a phahameng ka ho fetisisa a moralo.

Ho kopanya banyalani ka mahlakore ho lokela ho sebelisoa ka hohle kamoo ho ka khonehang ho qoba ho kopanya banyalani ba sephara, molaoana oa 3S o lokela ho sebelisoa ho qoba ho kopanya kapa ho fetisa mantsoe.

(7) Lintlha tsa ho sefa lerata bakeng sa lits’ebetso tse lebelo le holimo.

Fokotsa tšitiso ea maqhubu a tlase (ka tlase ho 1KHz) e bakiloeng ke lerata la mohloli oa matla, ‘me u kenye tšireletso kapa ho sefa potoloho qetellong ea phihlello ea mohloli oa matla.

Kenya filtara ea 100F ea electrolytic capacitor sebakeng se seng le se seng moo phepelo ea motlakase e kenang ho PCB.

Ho fokotsa lerata le maqhubu a phahameng, beha li-capacitor tse ngata ho Vcc le GND ka hohle kamoo ho ka khonehang.

Rala lifofane tsa Vcc le GND ka ho tšoana, li arohane ka dielectric (joalo ka FR-4PCB), ‘me u behe li-capacitor tse fetang ka likarolo tse ling.

(8) Sistimi e phahameng ea Ground Bounce

Leka ho kenyelletsa decoupling capacitor ho e ‘ngoe le e’ ngoe ea lipontšo tsa Vcc / GND.

Buffer ea kantle e eketsoa qetellong ea lipontšo tsa phetoho e potlakileng joalo ka li-counters ho fokotsa tlhoko ea bokhoni ba ho khanna.

Mokhoa oa Slow Slew (low-kupanda-slope) o ne o hlophiselitsoe lipontšo tse sa hlokeng lebelo le bohale.

Laola karabelo ea mojaro.

Fokotsa lets’oao la ho panya ha oache, kapa o e tsamaise ka mokhoa o ts’oanang ka hohle kamoo ho ka khonehang ho potoloha chip.

Letšoao le phallang khafetsa le haufi le pini ea GND ea chip kamoo ho ka khonehang.

Moralo oa potoloho ea nako e lumellanang e lokela ho qoba ho fetoha ha sehlahisoa hang hang.

Ho khelosa phepelo ea motlakase le mobu ho ka bapala karolo ho kenelleng ha matla ka kakaretso.