Which test should come first? Cold or Hot?

Guest

when testing a lot at ambient, cold, and hot, which should come first?

kool lang

Posted: Thu Apr 01, 2026 5:38 pm Post subject:

it depends on the requirement of device

Posted: Wed May 12, 2026 4:30 pm Post subject:

logistics can also play a part. if the tester used for one temp is located in another building, it might be better to do consecutive testing of the parts at the temps whose testers are in the same building. that way you don't need to ship parts back and forth between the 2 buildings just to do the 3-temp testing.

Guest

Ano ba naman kayo, di nyo alam?

Eh di kung ano sabihin ng boss natin na may 25% increase. Pag sinabi nya na hot muna, bago mag hot(ulit), pwede rin. Pag sinabi nya na wala nalang para mataas ang yield(para good job sya sa boss din nya) e di yon ang gagawin mo.

Pag yon ang ginawa mo, good boy ka sa boss mo.

shhhh... baka 25% increase ka rin next time....

Guest

Hi Cool;

The safe answer is really depends on the device and what the design or product engineer says...

But most parts I know (specially digital) the sequence would be cold ambient and hot. The reason for this is first you want to test at both extremes (cold and hot) to minimize test cost by eliminating early known defects which ambient cant catch. Now next question would be who will come first cold or hot. Usually, cold comes first than hot because after cold test there is still another test which is burn-in. Most of the defects at burn-in (at burn-in device is subjected to extremely high temp) were not really being sorted in the same manner at cold, ambient and hot. The only way to catch burn-in reject is to test at hot. There are other reasons aside from this.

Guest

Hi Cool,

It all depend on the product application.

If the product is a digital, then it should be tested at hot first. Why?
It is because most of the high speed digital product works worst on hot environment.Also, most of the digital parts produce lot of heat when they operate, specially those high speed one.

If the Product is an analog, you better test it at room first. Why, simply... cost. analog parts costs less than digital parts. Also, due to the circuit inside the device itself. It has reference current/voltage that are worst at high temp, which makes the part produce random noise. Analog products did'nt produce much heat.

It also, good to consult your design engineer about what is inside you device. Before you develop your test flow/program.