Testing equipment
The testing lab contains a number of high performance and expensive equipment. Acquaint yourselves with the equipment by reading the manuals to get the best out of them. Here is a list of instruments in the testing lab.
OrCAD Tips
Drawing Schematics
Use seperate symbols for electrolytic capacitors and surface mount capacitors.
While using electrolytic capacitors, pay attention to the positive and negative terminals. Terminal 1 in schematic should be connected to higher voltage and terminal 2 to lower voltage.
Maximum value of non-polar surface mount cap is 1uF (@ modi electronics, ritchie street).
Use seperate symbols for thru-hole resistors and surface mount resistors.
There is a pushbutton in Orcad to generate 'Bill Of Materials'. This will aid in determining which all components to purchase.
Printing Schematics
To save schematics as PDF, first you will need to install PDF995 ( a free software).
Change print setting to 'Landscape', and output as 'PDF995'.
Placement
Routing
Before starting to route, we must fix the width of each net. Tools–>Net–>Select from Spreadsheet. Here we can fix the min,typ and max width of each net. For GNDA and VDDA it is 12,50,100, and for other nets 12,25,50.
To start routing click 'Add/Edit Route Mode' button in the task bar.
Submission
.MAX file contains the layout and .DSN file contains the schematic.
Only the .MAX file needs to be submitted for fabrication. No need to generate the GERBER files.
The shape of the PCB need not necessarily be a square/rectangle.
PCB Fabrication / Component purchase
Fabrication
Printed Circuit Services(Zeta), I-1, Dr.V.S.I Estate, Near NIFT, Thiruvanmiyur. Ph: 22541641, 42150860, Email: plot@zetapcs.com
Tessolve
Type of material used : FR-4(an abbreviation for Flame Retardant 4, a glass reinforced epoxy laminate used for making printed circuit boards.)
Dielectric Constant: Varies according to the frequency applied and depends on the vendor.(A value of 4-4.5 seems to be appropriate for high frequency designs >1GHz)
Standard thickness of board: 1.6 mm
Thickness of copper trace: 35 µm
The above information can be used to determine the trace impedance.
Component Purchase
Modi Electronics, No 6, 1st floor, Ritchie Street. Ph: 28414140
Mercy Electronics, L.B Road, Adyar. Ph: 24464481
Mency Electronics, Tharamani Road, Velachery. Ph: 22434773, 42082097
Texonic, Ritchie Street. Ph: 28410638
Globe Tronics, Ritchie Street. (All kinds of male/female connectors, adapters etc.) Ph. No: 42119262, 42149503
SRICOM(Srinar Communications) (RF Cables, Connectors, and other accessories…)
http://www.sricomworld.in/; email : mtk@sricomworld.com
Ph.No : +91 9841005125 (Mr. Ismail)
Assembly