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 ….??