how to test ic

[sagarverma]

how can i test an ic without sticking it into the circuit in which it is intended towork.in a nutshell,how to test if the ic is working or not without putting it in the ckt.

 

[Netlist]

There is one simple answer: you can't.

/Hugo

 

[Christer]

Or more precisely, you can, but the simplest way is to plug it into the circuit.

 

[sss]

why it shouldnt work in the first place?

 

[Netlist]

Or more precisely, you can,

Did I answer too fast?

/Hugo

 

[Nordic]

What are the electrical test circuits in the datasheet for?

 

[Christer]

Did I answer too fast?

/Hugo

No, just too simply.


You are right in the sense that he would have to use some circuitry that actually uses the op amp (chip amp) as an amplifier, but it doesn't have to be the circuit it is intended to be used in. I guess that was my point.

 

[sagarverma]

so what r ic testers?
they test ics but cost a hell.they r general purpose.my purpose is for amp ics only

 

[Netlist]

What I had in mind was just a simple DMM and a universal answer. Go figure we had to go and measure a micro-controller (which is an IC as well) with an ohmmeter.
Even measuring an LM38XX wouldn't go that way.
Looking at the price of IC testers, and if you only want to test opamps I guess building a small test circuit with +/-15V, in and outputs or just plug it in some existing circuitry should do the trick.

/Hugo

 

[peranders]

Just wondering, do you ask this question in general or do you have used IC's which you want to test?

As you may have noticed the answer is yes and no.

 

[peranders]

What are the electrical test circuits in the datasheet for?

They are usually a simple circuit in order to get a basic function out of the IC.

 

[sagarverma]

opamp testing is a breeze.

i built that mini project to test upto quad amps.with three ic bases for standard pinouts.but opamp testing not on my mind.

i want an audio amp ic tester,better portable,batery driven so i can test ic on the spot at the shop.

my only ckt to go bust is tda7293 amp.ic burned out.isuspect it was jus a junk,nothing but simple metal plate inside.

any general purpose ckt in sight??

 

[dnsey]

Audio amp ICs come in so many configurations that a universal tester isn't really practical.
besides, if you test the IC in a shop with a homebrew circuit, and it fails, surely they will blame your cct and charge you anyway

 

[sagarverma]

thats y i m here.to b able to buid a full proof tester that test and not destroys

my main concern is audio amp tester(chip)

it should just make the chip sound

like that,some small alligators sticking out,joined to pins of i/p o/p power etc,small speaker variable supply of standard values.any plan??
tried anyone?advise??

 

[pinkmouse]

I suspect that it would cost you more money to build a fool proof tester than it would cost to throw away a few faulty chips that you might buy.

If you have more than one failure, (highly unlikely, if your circuit is ok), then it's easiest just to buy chips with a different batch code.

 

[sagarverma]

i wanna avoid the fake chips.the tda desroyed itself and the whole lot of components it was sticking with.
by testing the chips on the spot i will avoid buying junk in bulk.
circuit cam me made simple.i need advise regarding planning,layout,experiences and vital info etc.

 

[pinkmouse]

Just buy your chips from a reputable dealer then!

edit: To test properly, you might as well build another amp, as you need to test at full voltage and output, running into a suitable dummy load. Use a socket to mount the chip, and a clamp to fix a heatsink. You will then have to prove that any chips you blow up were fakes, or the dealer will likely charge you for them. Just buy from a real distributor, it's much easier...

 

[Netlist]

There’s a good chance that your test circuit will go up in smoke just as the amplifier did. Looking at the ‘Typical Application and Test Circuit’ in the datasheet there are quite some components to loose as well. On the other hand, this might probably be the simplest schematic to build as a test circuit and in the meantime you have build an amplifier.

/Hugo

 

[Christer]

The question is, what do you want to test? I suppose fakes come in many flavours, so there isn't one single test that catches them all.

Just some loose ideas:
- Current limited power supply and a check that the chip doesn't draw an insane amount of idle current.
- Some check that it indeed works as an amplifier. This could be something simple like connecting it as a voltage follower, a switch to choose say + and - 2 V at the input and LEDs at the output to verify the function

Things You don't catch this way are, for instance:
- open loop gain
- Frequency response
- power handling (How do you know they haven't just put a 741 in the package)

 

[sagarverma]

The question is, what do you want to test? I suppose fakes come in many flavours, so there isn't one single test that catches them all.

Just some loose ideas:
- Current limited power supply and a check that the chip doesn't draw an insane amount of idle current.
- Some check that it indeed works as an amplifier. This could be something simple like connecting it as a voltage follower, a switch to choose say + and - 2 V at the input and LEDs at the output to verify the function

Things You don't catch this way are, for instance:
- open loop gain
- Frequency response
- power handling (How do you know they haven't just put a 741 in the package)

good.thats the idea.

and also a problem

come up with its application(your idea)

Just buy your chips from a reputable dealer then!

for chips that i have usedand worked,the current dealer is now reputed