Lessons Learned with Source Controlled Drawings
(One in an occassional series of "Infomins" from ESCS)
Source controlled drawings
are created not only to document the characteristics of a component's data sheet but
also to prohibit the substitution of an untested manufacturer's equivalent.
The offering of a cross is common practice with commercial products, however while they may compare
in the case of voltage, frequency, and temperature, they may fail when subjected to the maximum tolerances
for reverse bias or heat dissipation. The engineers involved in the design may know something about the big
picture and how a particular component will be utilized in a circuit. After many failures they have decided
on a requirement that can only be filled by that one company's product.
#1 Lesson learned - Don't repeat their failures. Engineers are paid to make it fail, you will have to deal
with every facet of your production process when you make that same mistake. Many DSCC standard microcircuit
drawings - ie: 5962 - offer a choice of manufacturers that meet that QPL. Unless otherwise specified, you
should be safe in procuring any manufacturer's part that was QPL'd for that year. However if you check the
DSCC historical date for that device and the mfg being offered by the distributor was not QPL'd for that device
in the year of the date code being offered than you can assume the product is counterfeit.
Click here to learn how to do the DSCC Drill-Down yourself. It takes
just 30 seconds, and can save you and your company $$ thousands.
Source controlled drawings
are created not only to document the characteristics of a component's data sheet but
also to prohibit the substitution of an untested manufacturer's equivalent.
The offering of a cross is common practice with commercial products, however while they may compare
in the case of voltage, frequency, and temperature, they may fail when subjected to the maximum tolerances
for reverse bias or heat dissipation. The engineers involved in the design may know something about the big
picture and how a particular component will be utilized in a circuit. After many failures they have decided
on a requirement that can only be filled by that one company's product.