need help to learn IC testing

[vcsel_driver]

how to set up ic test house

i m a new test engineer. i m going to perform design verification on a 1.25gbps optical transmitter for starters.

my questions are:

1) what area do i start reading on?
2) is there any book to guide me. i have seen many books regarding design of analogue IC and layout but nothing about testing.
3) is it important for me to have layout and design knowledge?

 

[nathan80]

learn ic

well, it is hard to tell you where to begin reading.

from the fact you have mentioned optical transmitter; i think your company is a analogue IC design house...maybe doing mixmode IC's too...

i have worked for more than a year as a test engineer also (performing design verfication) in an analogue IC design house.

first you need to understand that you are not performing testing for mass production. (this type of testing is totally different and most reading materials are available for this)

you have to understand that :
your test chip is not designed 100% according to your customer specs yet.
your job is to validate and verify whether the design is correct; provide feedbacks to IC designers to improve the chip design n etc.
you might have to test whether the transmitter is emitting signals (in terms or photons; current or voltage) as required.
other tests also are required according to the functions and applications incorporated within the chip.

to start reading ; learn the basic building blocks of an optical transmitter.
what are modulation current , bias current
what are bandgap voltage reference?
what is temperature compensation?
are there any other functions incorporated within the chip.

find all this information in google or application notes from companies like zarlink, sires labs etc.

one more thing; start learning a bit on analogue circuit analysis ; cause its usefull when assisting designer to perform failure analysis (in future you will be able to perform FA urself). you can use sedra smith (can be downloaded from edaboard).

one more main skill is...learn how to use all the test equipment available in your test centre (ex: pulse pattern generator , sampling osciloscope , optical reader and attenuator, TDR probes, BER measurement devices, spectrum analysers , vector network analyzers.

You can pick up one by one skill as your job requires.

In my opinion; the most important thing to read about is the application notes about your chips functions.

Anyway I think I have mentioned a lot of things to cover;
Ps; there are a lot more areas to cover on… do mention if I did not mention it. Any queries, pls ask here…

 

[vcsel_driver]

wau, soo much info. but i need a little more help here as i need to begin testing next week

 

[nathan80]

can you be more specific. i have done optical tranmitter testing before.

i need to ask? do you have a evaluation board with the die attached to be tested?

or are you using a prob station to direct prob the die?

what equipments do you have in your test centre....

 

[vcsel_driver]

well, i will be shown how to setup the test station for the first time.
using evaluation board.
i just need some notes with diagram how is it done.
do you have any?

 

[nathan80]

well, i guess you are still very new and looking for materials to read.

you should make an iniciative browsing in google, alta vista... to find info..

i am including two url's that can give you some knowledge on optical transmitters.

**broken link removed**

**broken link removed**

let me give you a list of questions for you to find answer, that way you will learn faster;

1) what is the function of an optical transmitter?
2) which standard does the transmitter use; LVPECL, LVDS or other standards?
3) is your transmitter used for VSR applications or for what applications?
4) is your transmitter using CMOS or BiCMOS technology? what design kit was used for fabrication? which cadence toold were used for design and layout?
5) the most effective way to determine functionality of a transmitter IC is by connecting it to the receiver and checking the BER of the transmitted signal. are we testing the functionality of the transmittor this way? if not what way are we testing the optical transmitter?
6) what is a vcsel source? what is a photodiode? how is conversions between current and voltage done inside a receiver and a transmitter.
7) what is a TIA? what is a LA? what are the building blocks or a transmitter? what are the building blocks of a receiver?
8)how is the bare die connected to the evaluation (PCB board)? is it using wirebonds? what type of wirebonds? how are the wire bonds protected? what type of components are used in the evaluation board (RoHS, high frequency components or what)?
9) what other functions does the optical transmitter have? (this info can be found in the IC's application notes).
10) do you measure the eye diagram of the optical transmitter for testing? what PRBS pattern are used to generate the eye diagram? which equipment supplies the pattern signal? which equipment measures the eye? what are the following:
extinction ratio, average optical power, rise time, fall time, jitter. how to measure modulation current , bias current? what type of jitters are available?
what is K28.5 pattern?
11) what is the wavelength of the signal to be transmitter using the transmitter?
12) what is TDR probing?

well this is all i could think off now? hope u find the answers... i m sure it will help to improve your test knowledge and skills.

more questions to ask:
how to analyze an eye diagram?
what is a differential signal?
what is single ended signal?
what is a mask test of an eye diagram?
how to determine if the eye is open or closed? what are we supposed to look at?


one more thing: you can try browsing test equipments application notes, example and setup notes - you will be suprised how much info you can get from there.
try agilent and textronics websites.