Strategi Merekabentuk Papan Litar Tercetak (PCB)

KL 3083 Rekabentuk SistemHilmi Sanusi

Strategi Awal• Spesifikasi

– Dimensi– Susun-atur komponen

• Aplikasi– Kegunaan alat pada tahap frekuensi:

• DC• Frekuensi rendah• Julat audio• Frekuensi tinggi• Gelombang mikro

– Persekitaran• Hingar dari EMC – RFI dan EMI• Julat suhu

Spesifikasi

Akan menghadkan rekabentuk dari segi• Kekangan bentuk

– dimensi, bulat, bujur, segi empat tepat dll bentuk PCB

• Kekangan susun-atur komponen – input, – output, – penyesaran haba, – bypass capacitor

Aplikasi Litar• Keperluan yang sesuai bagi rekaan PCB

– pembumian – lebar track – jenis dielectric – ketebalan track

• Keperluan bagi track– Arus– Isyarat yang melaluinya

• Analog• Digital

• Gangguan dari perambatan yang terhasil dari arus yang mengalir dalam track

Hasil dari keperluan litar• Jenis pembumian yang sesuai• Penyusunan modular melalui segmen

– interaksi EMC• Jenis track

– Bus– track corner– junction

• Jenis pad – luas pad– kedudukan pad– jenis pad

• Jenis penyambungan– Jumper– via

PCB

Low Frequency High frequency

DC

Low frequency < 400Hz

Audio range

High frequency

Microwave

•Noise Interference•Power line modulation•Back propagation from switchingsingle layerDouble layer (Isolation)grounding

•Emc – rfi & emi•Capacitive and inductive effect of the track and patch•Track corner•Shielding effect•Skin effectMultiple layerTwo layer (microstrip)

Application

Operating frequency Dimension limitation and component Specification

•Track width•Type of ground•Interconnect

•Component selection •to satisfy the •Specification•Footprint of the •selected component

•Segmentation •Modular

What are the information needed

• Layer / type of the board • EMC• Track width• Overall design

– Modular / segment / component placement– PCB shape and dimension limitation– Components selection

• Footprint and dimension

Overall design

Overall design

Overall design

Components selection

Dimension Footprint Usage - Tolerance - specification - rating

Module (PCB) placement in the system

Circuit – BOM (specification)

Components selection• Based on

– Rating– Specification– dimension

Components footprint

Components dimension

Components: dimension and footprint

Components: dimension and footprint

PCB - dimension

Placement of components

Placement of components pad (footprint)

Routing of the track

Routing of the track

Adjustment to the components

Re-routing of the track

Track of the PCB

Component side of the PCB

PCB software: example

schematic diagram: netlist

Rat-nest of the netlist

Interconnect: via

Simple Quiz ….??