{"id":4722,"date":"2026-02-25T06:02:44","date_gmt":"2026-02-25T06:02:44","guid":{"rendered":"https:\/\/flj-pcb.com\/?p=4722"},"modified":"2026-02-25T06:02:48","modified_gmt":"2026-02-25T06:02:48","slug":"why-via-impedance-is-hard-to-control","status":"publish","type":"post","link":"https:\/\/flj-pcb.com\/vi\/why-via-impedance-is-hard-to-control\/","title":{"rendered":"T\u1ea1i sao vi\u1ec7c ki\u1ec3m so\u00e1t tr\u1edf kh\u00e1ng l\u00e0 kh\u00f3 kh\u0103n"},"content":{"rendered":"

Ch\u00fang t\u00f4i \u0111\u1ebfn m\u1ed9t c\u1eeda h\u00e0ng PCB v\u00e0 h\u1ecfi h\u1ecd: \u201cC\u00e1c b\u1ea1n c\u00f3 th\u1ec3 \u0111i\u1ec1u ch\u1ec9nh tr\u1edf kh\u00e1ng \u0111\u01b0\u1eddng d\u1eabn xu\u1ed1ng m\u1ee9c 10% kh\u00f4ng?\u201d H\u1ecd s\u1ebd tr\u1ea3 l\u1eddi b\u1ea1n m\u1ed9t c\u00e1ch t\u1ef1 tin: \u201cKh\u00f4ng v\u1ea5n \u0111\u1ec1 g\u00ec!\u201d N\u1ebfu b\u1ea1n \u0111\u00f2i h\u1ecfi th\u00eam m\u1ed9t ch\u00fat v\u00e0 y\u00eau c\u1ea7u 8%, h\u1ecd c\u00f3 th\u1ec3 suy ngh\u0129 m\u1ed9t l\u00e1t r\u1ed3i n\u00f3i: \u201c\u0110\u01b0\u1ee3c th\u00f4i (\u0111\u1ed1i v\u1edbi c\u00e1c l\u1edbp b\u00ean trong)!\u201d N\u1ebfu b\u1ea1n h\u1ecfi ti\u1ebfp: \u201cLi\u1ec7u l\u1ed7 via c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c ki\u1ec3m so\u00e1t \u1edf m\u1ee9c 10% kh\u00f4ng?\u201d, con thuy\u1ec1n t\u00ecnh b\u1ea1n nh\u1ecf b\u00e9 \u0111\u00f3 c\u00f3 th\u1ec3\u2026 l\u1eadt \u00fap!<\/p>\n\n\n\n

C\u00e2u h\u1ecfi c\u1ed1t l\u00f5i: Dung sai tr\u1edf kh\u00e1ng c\u1ee7a \u0111\u01b0\u1eddng d\u1eabn so v\u1edbi l\u1ed7 th\u00f4ng<\/h2>\n\n\n\n

C\u1ea3 \u0111\u01b0\u1eddng d\u1eabn v\u00e0 l\u1ed7 vias \u0111\u1ec1u k\u1ebft n\u1ed1i c\u00e1c chip thu ph\u00e1t. V\u1eady t\u1ea1i sao \u0111\u01b0\u1eddng d\u1eabn c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c duy tr\u00ec \u1edf m\u1ee9c 10% trong khi l\u1ed7 vias l\u1ea1i kh\u00f4ng th\u1ec3? Ch\u00fang ta bi\u1ebft r\u1eb1ng vi\u1ec7c ki\u1ec3m so\u00e1t \u0111\u01b0\u1eddng d\u1eabn c\u0169ng kh\u00f4ng h\u1ec1 d\u1ec5 d\u00e0ng. C\u00e1c y\u1ebfu t\u1ed1 \u1ea3nh h\u01b0\u1edfng \u0111\u1ebfn tr\u1edf kh\u00e1ng c\u1ee7a \u0111\u01b0\u1eddng d\u1eabn bao g\u1ed3m h\u1ec7 s\u1ed1 \u0103n m\u00f2n, \u0111\u1ed9 l\u1ec7ch l\u1edbp v\u00e0 \u0111\u1ed9 nh\u00e1m b\u1ec1 m\u1eb7t. \u0110\u1ed1i v\u1edbi \u0111\u01b0\u1eddng d\u00e2y microstrip, l\u1edbp ph\u1ee7 h\u00e0n v\u00e0 \u0111\u1ed9 d\u00e0y \u0111\u1ed3ng c\u0169ng r\u1ea5t quan tr\u1ecdng. Tuy nhi\u00ean, nhi\u1ec1u x\u01b0\u1edfng s\u1ea3n xu\u1ea5t b\u1ea3ng m\u1ea1ch ch\u00ednh th\u1ed1ng v\u1eabn c\u00f3 th\u1ec3 \u0111\u1ea3m b\u1ea3o dung sai tr\u1edf kh\u00e1ng 10% ho\u1eb7c th\u1eadm ch\u00ed 8% cho c\u00e1c \u0111\u01b0\u1eddng d\u1eabn. \u0110\u1ed1i v\u1edbi l\u1ed7 th\u00f4ng, theo nh\u1eefng g\u00ec t\u00f4i bi\u1ebft v\u1ec1 c\u00e1c x\u01b0\u1edfng s\u1ea3n xu\u1ea5t b\u1ea3ng m\u1ea1ch, kh\u00f4ng c\u00f3 x\u01b0\u1edfng n\u00e0o h\u1ee9a h\u1eb9n s\u1ebd ki\u1ec3m so\u00e1t tr\u1edf kh\u00e1ng l\u1ed7 th\u00f4ng trong ph\u1ea1m vi 10%. \u0110i\u1ec1u \u0111\u00f3 c\u00f3 ngh\u0129a l\u00e0 c\u00f3 nhi\u1ec1u y\u1ebfu t\u1ed1 li\u00ean quan \u0111\u1ebfn l\u1ed7 th\u00f4ng m\u00e0 c\u00e1c x\u01b0\u1edfng s\u1ea3n xu\u1ea5t b\u1ea3ng m\u1ea1ch kh\u00f4ng th\u1ec3 ki\u1ec3m so\u00e1t, do \u0111\u00f3 h\u1ecd kh\u00f4ng th\u1ec3 \u0111\u1ea3m b\u1ea3o \u0111i\u1ec1u n\u00e0y.<\/p>\n\n\n\n

N\u1ed9i dung b\u00e0i vi\u1ebft n\u00e0y \u0111\u1ec1 c\u1eadp \u0111\u1ebfn nh\u1eefng g\u00ec<\/h2>\n\n\n\n

Trong b\u00e0i vi\u1ebft n\u00e0y, tr\u01b0\u1edbc ti\u00ean t\u00f4i s\u1ebd gi\u1edbi thi\u1ec7u hai quy tr\u00ecnh li\u00ean quan \u0111\u1ebfn l\u1ed7 via: khoan v\u00e0 l\u1ea5p \u0111\u1ea7y l\u1ed7 via. Nhi\u1ec1u ng\u01b0\u1eddi bi\u1ebft r\u1eb1ng vi\u1ec7c khoan r\u1ea5t quan tr\u1ecdng, nh\u01b0ng \u0111\u1ed9 dung sai khi khoan \u1ea3nh h\u01b0\u1edfng \u0111\u1ebfn hi\u1ec7u su\u1ea5t c\u1ee7a l\u1ed7 via \u0111\u1ebfn m\u1ee9c n\u00e0o? \u0110\u1ed1i v\u1edbi vi\u1ec7c l\u1ea5p \u0111\u1ea7y, nhi\u1ec1u ng\u01b0\u1eddi cho r\u1eb1ng vi\u1ec7c l\u1ea5p \u0111\u1ea7y l\u1ed7 via b\u1eb1ng nh\u1ef1a ho\u1eb7c l\u1edbp ph\u1ee7 ch\u1ed1ng h\u00e0n s\u1ebd l\u00e0m thay \u0111\u1ed5i hi\u1ec7u su\u1ea5t c\u1ee7a l\u1ed7 via. Ch\u00fang t\u00f4i \u0111\u00e3 ki\u1ec3m tra nh\u1eefng t\u00e1c \u0111\u1ed9ng n\u00e0y th\u00f4ng qua m\u00f4 ph\u1ecfng.<\/p>\n\n\n\n

1. Quy tr\u00ecnh khoan v\u00e0 t\u00e1c \u0111\u1ed9ng c\u1ee7a n\u00f3 \u0111\u1ed1i v\u1edbi hi\u1ec7u su\u1ea5t c\u1ee7a l\u1ed7 d\u1eabn<\/h2>\n\n\n\n

\u0110\u1ea7u ti\u00ean l\u00e0 qu\u00e1 tr\u00ecnh khoan. Ch\u00fang ta th\u01b0\u1eddng nghe \u0111\u1ebfn hai thu\u1eadt ng\u1eef: k\u00edch th\u01b0\u1edbc m\u0169i khoan v\u00e0 k\u00edch th\u01b0\u1edbc l\u1ed7 ho\u00e0n thi\u1ec7n. N\u1ebfu ch\u00fang ta thi\u1ebft k\u1ebf m\u1ed9t l\u1ed7 c\u00f3 \u0111\u01b0\u1eddng k\u00ednh 8 mil trong t\u1ec7p PCB, b\u1ea1n c\u00f3 ngh\u0129 nh\u00e0 m\u00e1y s\u1ebd s\u1eed d\u1ee5ng m\u0169i khoan 8 mil kh\u00f4ng? T\u1ea5t nhi\u00ean l\u00e0 kh\u00f4ng. M\u1ed9t l\u1ed7 via ph\u1ea3i k\u1ebft n\u1ed1i c\u00e1c \u0111\u01b0\u1eddng d\u1eabn tr\u00ean c\u00e1c l\u1edbp kh\u00e1c nhau. L\u1ed7 n\u00e0y ph\u1ea3i \u0111\u01b0\u1ee3c m\u1ea1 \u0111\u1ed3ng \u0111\u1ec3 \u0111\u1ed3ng ch\u1ea1y th\u1eb3ng \u0111\u1ee9ng xuy\u00ean qua l\u1ed7. \u0110\u00f3 ch\u00ednh l\u00e0 \u0111\u1ed3ng m\u1ea1 xuy\u00ean l\u1ed7. Theo ti\u00eau chu\u1ea9n IPC, \u0111\u1ed9 d\u00e0y \u0111\u1ed3ng m\u1ea1 xuy\u00ean qua c\u00f3 c\u00e1c y\u00eau c\u1ea7u nh\u1ea5t \u0111\u1ecbnh, kho\u1ea3ng 18 \u00b5m \u0111\u1ebfn 20 \u00b5m. V\u00ec v\u1eady, c\u00e1c nh\u00e0 m\u00e1y \u0111\u1ea3m b\u1ea3o l\u1ed7 c\u00f3 k\u00edch th\u01b0\u1edbc 8 mil sau khi m\u1ea1. K\u00edch th\u01b0\u1edbc cu\u1ed1i c\u00f9ng \u0111\u00f3 l\u00e0 l\u1ed7 ho\u00e0n thi\u1ec7n. \u0110i\u1ec1u \u0111\u00f3 c\u00f3 ngh\u0129a l\u00e0 k\u00edch th\u01b0\u1edbc m\u0169i khoan ban \u0111\u1ea7u ph\u1ea3i l\u1edbn h\u01a1n 8 mil. L\u1edbn h\u01a1n bao nhi\u00eau? 10 mil? 12 mil? S\u1ef1 ch\u00eanh l\u1ec7ch k\u00edch th\u01b0\u1edbc n\u00e0y c\u00f3 \u1ea3nh h\u01b0\u1edfng l\u1edbn \u0111\u1ebfn hi\u1ec7u su\u1ea5t c\u1ee7a l\u1ed7 th\u00f4ng.<\/p>\n\n\n\n

Theo c\u00e1c quy t\u1eafc v\u1ec1 dung sai khoan c\u1ee7a nh\u00e0 m\u00e1y, \u0111\u1ec3 t\u1ea1o ra l\u1ed7 ho\u00e0n thi\u1ec7n c\u00f3 \u0111\u01b0\u1eddng k\u00ednh 0,2 mm (8 mil), ng\u01b0\u1eddi ta s\u1ebd s\u1eed d\u1ee5ng m\u0169i khoan c\u00f3 \u0111\u01b0\u1eddng k\u00ednh \u00edt nh\u1ea5t l\u00e0 0,25 mm (10 mil). N\u1ebfu b\u1ea1n kh\u00f4ng y\u00eau c\u1ea7u ki\u1ec3m so\u00e1t ch\u1eb7t ch\u1ebd h\u01a1n, nh\u00e0 m\u00e1y c\u00f3 th\u1ec3 s\u1eed d\u1ee5ng m\u0169i khoan c\u00f3 \u0111\u01b0\u1eddng k\u00ednh 0,3 mm (12 mil). Ai c\u0169ng bi\u1ebft r\u1eb1ng m\u0169i khoan l\u1edbn h\u01a1n s\u1ebd l\u00e0m gi\u1ea3m tr\u1edf kh\u00e1ng. Nh\u01b0ng gi\u1ea3m bao nhi\u00eau? K\u1ebft qu\u1ea3 m\u00f4 ph\u1ecfng c\u1ee7a ch\u00fang t\u00f4i s\u1ebd cho b\u1ea1n th\u1ea5y.<\/p>\n\n\n\n

K\u1ebft qu\u1ea3 m\u00f4 ph\u1ecfng cho th\u1ea5y c\u00e1c l\u1ed7 vias c\u00f3 \u0111\u01b0\u1eddng k\u00ednh t\u1eeb 0,2 mm \u0111\u1ebfn 0,3 mm c\u00f3 s\u1ef1 ch\u00eanh l\u1ec7ch tr\u1edf kh\u00e1ng l\u1edbn h\u01a1n 5 ohm.<\/p>\n\n\n\n

N\u1ebfu xem x\u00e9t c\u00e1c t\u1ed5n th\u1ea5t do \u0111\u01b0\u1eddng d\u1eabn g\u00e2y ra, ch\u00fang ta c\u0169ng c\u00f3 th\u1ec3 th\u1ea5y nh\u1eefng \u0111i\u1ec3m kh\u00e1c bi\u1ec7t r\u00f5 r\u1ec7t.<\/p>\n\n\n\n

\u0110\u1ed1i v\u1edbi quy tr\u00ecnh khoan \u0111\u01a1n l\u1ebb n\u00e0y, ch\u1ec9 ri\u00eang dung sai gia c\u00f4ng c\u0169ng c\u00f3 th\u1ec3 g\u00e2y ra \u0111\u1ed9 dao \u0111\u1ed9ng l\u1edbn h\u01a1n 10%.<\/p>\n\n\n\n

2. Ph\u01b0\u01a1ng ph\u00e1p \u0111i\u1ec1n: M\u00f4 ph\u1ecfng v\u00e0 k\u1ebft qu\u1ea3<\/h2>\n\n\n\n

B\u00e2y gi\u1edd n\u00f3i v\u1ec1 vi\u1ec7c l\u1ea5p \u0111\u1ea7y l\u1ed7 via. Nhi\u1ec1u b\u1ea1n b\u00e8 \u0111\u00e3 h\u1ecfi li\u1ec7u vi\u1ec7c l\u1ea5p \u0111\u1ea7y l\u1ed7 via c\u00f3 \u1ea3nh h\u01b0\u1edfng \u0111\u1ebfn hi\u1ec7u su\u1ea5t c\u1ee7a l\u1ed7 via hay kh\u00f4ng. T\u00f4i c\u1ee9 n\u00f3i v\u1edbi h\u1ecd: \u201cKh\u00f4ng \u1ea3nh h\u01b0\u1edfng g\u00ec c\u1ea3! Kh\u00f4ng \u1ea3nh h\u01b0\u1edfng g\u00ec c\u1ea3!\u201d H\u1ecd tin t\u00f4i, nh\u01b0ng v\u1eabn c\u00f2n m\u1ed9t ch\u00fat nghi ng\u1edd. V\u00ec v\u1eady, t\u00f4i \u0111\u00e3 th\u1ef1c hi\u1ec7n c\u00e1c m\u00f4 ph\u1ecfng \u0111\u1ec3 ki\u1ec3m tra.<\/p>\n\n\n\n

H\u00ecnh d\u01b0\u1edbi \u0111\u00e2y cho th\u1ea5y c\u00e1c m\u1eabu l\u1ed7 vias ch\u01b0a \u0111\u01b0\u1ee3c l\u1ea5p \u0111\u1ea7y v\u00e0 \u0111\u00e3 \u0111\u01b0\u1ee3c l\u1ea5p \u0111\u1ea7y. M\u00e0u \u0111\u1ecf bi\u1ec3u th\u1ecb nh\u1ef1a ho\u1eb7c l\u1edbp ph\u1ee7 ch\u1ed1ng h\u00e0n l\u1ea5p \u0111\u1ea7y l\u1ed7 via.<\/p>\n\n\n\n

\"Return<\/figure>\n\n\n\n

Ch\u00fang t\u00f4i \u0111\u00e3 so s\u00e1nh t\u1ed5n th\u1ea5t ph\u1ea3n x\u1ea1 v\u00e0 t\u1ed5n th\u1ea5t ch\u00e8n cho hai tr\u01b0\u1eddng h\u1ee3p n\u00e0y. T\u1ea1i sao ch\u1ec9 c\u00f3 m\u1ed9t \u0111\u01b0\u1eddng? B\u1edfi v\u00ec hai \u0111\u01b0\u1eddng n\u00e0y ch\u1ed3ng l\u00ean nhau. T\u1ea1i sao ch\u00fang l\u1ea1i ch\u1ed3ng l\u00ean nhau? B\u1edfi v\u00ec kh\u00f4ng c\u00f3 s\u1ef1 kh\u00e1c bi\u1ec7t. K\u1ebft qu\u1ea3 l\u00e0 nh\u01b0 nhau.<\/p>\n\n\n\n

L\u00fd do l\u00fd thuy\u1ebft: T\u1ea1i sao vi\u1ec7c l\u1ea5p \u0111\u1ea7y l\u1ea1i kh\u00f4ng quan tr\u1ecdng<\/h2>\n\n\n\n

B\u1ea5t k\u1ef3 ai c\u00f3 ki\u1ebfn th\u1ee9c v\u1ec1 l\u00fd thuy\u1ebft t\u1ed1c \u0111\u1ed9 cao \u0111\u1ec1u bi\u1ebft r\u1eb1ng \u1edf t\u1ed1c \u0111\u1ed9 cao, t\u00edn hi\u1ec7u s\u1ebd xu\u1ea5t hi\u1ec7n hi\u1ec7n t\u01b0\u1ee3ng hi\u1ec7u \u1ee9ng b\u1ec1 m\u1eb7t. T\u00edn hi\u1ec7u s\u1ebd truy\u1ec1n d\u1ecdc theo b\u1ec1 m\u1eb7t b\u00ean ngo\u00e0i c\u1ee7a l\u1ed7 d\u1eabn. Do \u0111\u00f3, b\u1ea5t k\u1ec3 v\u1eadt li\u1ec7u \u0111i\u1ec7n m\u00f4i b\u00ean trong l\u1ed7 d\u1eabn l\u00e0 g\u00ec, tr\u01b0\u1eddng \u0111i\u1ec7n t\u1eeb gi\u1eefa t\u00edn hi\u1ec7u v\u00e0 \u0111i\u1ec3m tham chi\u1ebfu c\u0169ng kh\u00f4ng lan t\u1ecfa v\u00e0o b\u00ean trong. N\u1ebfu kh\u00f4ng c\u00f3 tr\u01b0\u1eddng \u0111i\u1ec7n t\u1eeb b\u00ean trong, th\u00ec v\u1eadt li\u1ec7u b\u00ean trong l\u1ed7 d\u1eabn s\u1ebd kh\u00f4ng c\u00f3 t\u00e1c \u0111\u1ed9ng g\u00ec.<\/p>","protected":false},"excerpt":{"rendered":"

We went to a PCB shop and asked them: \u201cCan you control trace impedance to within 10%?\u201d They would answer […]<\/p>","protected":false},"author":1,"featured_media":4723,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_uag_custom_page_level_css":"","site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[36,30],"tags":[253,249,251,247,254,204,250,248,252,54,255],"class_list":["post-4722","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-pcb-design","category-pcb-manufacturers","tag-finished-hole-size","tag-high-speed-pcb-design","tag-insertion-loss","tag-pcb-drilling-tolerance","tag-pcb-impedance-control","tag-pcb-manufacturing-process","tag-pcb-via-impedance","tag-plated-through-hole","tag-return-loss","tag-signal-integrity","tag-via-filling"],"spectra_custom_meta":{"_edit_lock":["1771999449:1"],"rank_math_internal_links_processed":["1"],"rank_math_primary_category":["36"],"rank_math_seo_score":["10"],"_thumbnail_id":["4723"],"_uag_custom_page_level_css":[""],"site-sidebar-layout":["default"],"site-content-layout":[""],"ast-site-content-layout":["default"],"site-content-style":["default"],"site-sidebar-style":["default"],"ast-global-header-display":[""],"ast-banner-title-visibility":[""],"ast-main-header-display":[""],"ast-hfb-above-header-display":[""],"ast-hfb-below-header-display":[""],"ast-hfb-mobile-header-display":[""],"site-post-title":[""],"ast-breadcrumbs-content":[""],"ast-featured-img":[""],"footer-sml-layout":[""],"theme-transparent-header-meta":[""],"adv-header-id-meta":[""],"stick-header-meta":[""],"header-above-stick-meta":[""],"header-main-stick-meta":[""],"header-below-stick-meta":[""],"astra-migrate-meta-layouts":["default"],"ast-page-background-enabled":["default"],"ast-page-background-meta":["a:3:{s:7:\"desktop\";a:12:{s:16:\"background-color\";s:25:\"var(--ast-global-color-5)\";s:16:\"background-image\";s:0:\"\";s:17:\"background-repeat\";s:6:\"repeat\";s:19:\"background-position\";s:13:\"center center\";s:15:\"background-size\";s:4:\"auto\";s:21:\"background-attachment\";s:6:\"scroll\";s:15:\"background-type\";s:0:\"\";s:16:\"background-media\";s:0:\"\";s:12:\"overlay-type\";s:0:\"\";s:13:\"overlay-color\";s:0:\"\";s:15:\"overlay-opacity\";s:0:\"\";s:16:\"overlay-gradient\";s:0:\"\";}s:6:\"tablet\";a:12:{s:16:\"background-color\";s:0:\"\";s:16:\"background-image\";s:0:\"\";s:17:\"background-repeat\";s:6:\"repeat\";s:19:\"background-position\";s:13:\"center center\";s:15:\"background-size\";s:4:\"auto\";s:21:\"background-attachment\";s:6:\"scroll\";s:15:\"background-type\";s:0:\"\";s:16:\"background-media\";s:0:\"\";s:12:\"overlay-type\";s:0:\"\";s:13:\"overlay-color\";s:0:\"\";s:15:\"overlay-opacity\";s:0:\"\";s:16:\"overlay-gradient\";s:0:\"\";}s:6:\"mobile\";a:12:{s:16:\"background-color\";s:0:\"\";s:16:\"background-image\";s:0:\"\";s:17:\"background-repeat\";s:6:\"repeat\";s:19:\"background-position\";s:13:\"center center\";s:15:\"background-size\";s:4:\"auto\";s:21:\"background-attachment\";s:6:\"scroll\";s:15:\"background-type\";s:0:\"\";s:16:\"background-media\";s:0:\"\";s:12:\"overlay-type\";s:0:\"\";s:13:\"overlay-color\";s:0:\"\";s:15:\"overlay-opacity\";s:0:\"\";s:16:\"overlay-gradient\";s:0:\"\";}}"],"ast-content-background-meta":["a:3:{s:7:\"desktop\";a:12:{s:16:\"background-color\";s:25:\"var(--ast-global-color-4)\";s:16:\"background-image\";s:0:\"\";s:17:\"background-repeat\";s:6:\"repeat\";s:19:\"background-position\";s:13:\"center center\";s:15:\"background-size\";s:4:\"auto\";s:21:\"background-attachment\";s:6:\"scroll\";s:15:\"background-type\";s:0:\"\";s:16:\"background-media\";s:0:\"\";s:12:\"overlay-type\";s:0:\"\";s:13:\"overlay-color\";s:0:\"\";s:15:\"overlay-opacity\";s:0:\"\";s:16:\"overlay-gradient\";s:0:\"\";}s:6:\"tablet\";a:12:{s:16:\"background-color\";s:25:\"var(--ast-global-color-4)\";s:16:\"background-image\";s:0:\"\";s:17:\"background-repeat\";s:6:\"repeat\";s:19:\"background-position\";s:13:\"center center\";s:15:\"background-size\";s:4:\"auto\";s:21:\"background-attachment\";s:6:\"scroll\";s:15:\"background-type\";s:0:\"\";s:16:\"background-media\";s:0:\"\";s:12:\"overlay-type\";s:0:\"\";s:13:\"overlay-color\";s:0:\"\";s:15:\"overlay-opacity\";s:0:\"\";s:16:\"overlay-gradient\";s:0:\"\";}s:6:\"mobile\";a:12:{s:16:\"background-color\";s:25:\"var(--ast-global-color-4)\";s:16:\"background-image\";s:0:\"\";s:17:\"background-repeat\";s:6:\"repeat\";s:19:\"background-position\";s:13:\"center center\";s:15:\"background-size\";s:4:\"auto\";s:21:\"background-attachment\";s:6:\"scroll\";s:15:\"background-type\";s:0:\"\";s:16:\"background-media\";s:0:\"\";s:12:\"overlay-type\";s:0:\"\";s:13:\"overlay-color\";s:0:\"\";s:15:\"overlay-opacity\";s:0:\"\";s:16:\"overlay-gradient\";s:0:\"\";}}"],"footnotes":[""],"_elementor_edit_mode":[""],"_elementor_template_type":[""],"_elementor_data":[""],"_elementor_conditions":["a:0:{}"],"_edit_last":["1"],"_uag_css_file_name":["uag-css-4722.css"],"_uag_js_file_name":["uag-js-4722.js"],"_elementor_page_assets":["a:0:{}"]},"uagb_featured_image_src":{"full":["https:\/\/flj-pcb.com\/wp-content\/uploads\/2026\/02\/Why-Via-Impedance-Is-Hard-to-Control.webp",800,344,false],"thumbnail":["https:\/\/flj-pcb.com\/wp-content\/uploads\/2026\/02\/Why-Via-Impedance-Is-Hard-to-Control-150x150.webp",150,150,true],"medium":["https:\/\/flj-pcb.com\/wp-content\/uploads\/2026\/02\/Why-Via-Impedance-Is-Hard-to-Control-300x129.webp",300,129,true],"medium_large":["https:\/\/flj-pcb.com\/wp-content\/uploads\/2026\/02\/Why-Via-Impedance-Is-Hard-to-Control-768x330.webp",768,330,true],"large":["https:\/\/flj-pcb.com\/wp-content\/uploads\/2026\/02\/Why-Via-Impedance-Is-Hard-to-Control.webp",800,344,false],"1536x1536":["https:\/\/flj-pcb.com\/wp-content\/uploads\/2026\/02\/Why-Via-Impedance-Is-Hard-to-Control.webp",800,344,false],"2048x2048":["https:\/\/flj-pcb.com\/wp-content\/uploads\/2026\/02\/Why-Via-Impedance-Is-Hard-to-Control.webp",800,344,false],"trp-custom-language-flag":["https:\/\/flj-pcb.com\/wp-content\/uploads\/2026\/02\/Why-Via-Impedance-Is-Hard-to-Control-18x8.webp",18,8,true]},"uagb_author_info":{"display_name":"Philifast","author_link":"https:\/\/flj-pcb.com\/vi\/author\/2475017442jygmail-com\/"},"uagb_comment_info":0,"uagb_excerpt":"We went to a PCB shop and asked them: \u201cCan you control trace impedance to within 10%?\u201d They would answer […]","_links":{"self":[{"href":"https:\/\/flj-pcb.com\/vi\/wp-json\/wp\/v2\/posts\/4722","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/flj-pcb.com\/vi\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/flj-pcb.com\/vi\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/flj-pcb.com\/vi\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/flj-pcb.com\/vi\/wp-json\/wp\/v2\/comments?post=4722"}],"version-history":[{"count":1,"href":"https:\/\/flj-pcb.com\/vi\/wp-json\/wp\/v2\/posts\/4722\/revisions"}],"predecessor-version":[{"id":4725,"href":"https:\/\/flj-pcb.com\/vi\/wp-json\/wp\/v2\/posts\/4722\/revisions\/4725"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/flj-pcb.com\/vi\/wp-json\/wp\/v2\/media\/4723"}],"wp:attachment":[{"href":"https:\/\/flj-pcb.com\/vi\/wp-json\/wp\/v2\/media?parent=4722"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/flj-pcb.com\/vi\/wp-json\/wp\/v2\/categories?post=4722"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/flj-pcb.com\/vi\/wp-json\/wp\/v2\/tags?post=4722"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}