SN74LV244A: How check or verify the Buffer is damaged or not functioning

Willer Justinvil

Part Number: SN74LV244A
Other Parts Discussed in Thread: TINA-TI

Hi All,

I have the following Buffer IC from TI 74LV244 below. How I check whether the chip bad or damaged or data is passing through? Any help direction would be greatly appreciated

Thanks,

over 2 years ago

0 Clemens Ladisch over 2 years ago

Guru 243910 points

Apply changing signals to the inputs, and check whether the outputs follow.

0 Willer Justinvil over 2 years ago in reply to Clemens Ladisch

Prodigy 30 points

Hi Clemens,

Thanks for the reply. Do you think I could use the changing signals as Vcc and GND as input and check the outputs

Thanks,

0 Clemens Ladisch over 2 years ago in reply to Willer Justinvil

Guru 243910 points

Why would you want to power down the chip? And GND must never have a larger voltage than any of the other pins.

0 Willer Justinvil over 2 years ago in reply to Clemens Ladisch

Prodigy 30 points

Hi Clemens,

This is what I was hoping to do, Would this be a problem? any additional ideas would be greatly appreciated

Thanks

0 Emrys Maier over 2 years ago in reply to Willer Justinvil

TI__Guru* 96591 points

Hi WJ,

All inputs that are unused should be terminated at VCC or GND when you're testing. Unused outputs should be left disconnected.

You need to pull 1OE\ and 2OE\ to GND to activate the outputs (unless you want to test the high-impedance mode -- it looks like you don't).

Your input signal should go from 0V (low) to 3.3V (high) if the supply is 3.3V.

You can load the output with a 1kohm resistor divider to see if the output is weak - a weak output will not be able to drive all the way to the rail. I have attached an example circuit in a Tina-TI simulation so you can see the expected operation.

LV244_Test-Circuit-Example.TSC

0 Willer Justinvil over 2 years ago in reply to Emrys Maier

Prodigy 30 points

Emrys,

Thank you for the Tina-TI simulation, I have never used the Tina simulation before. The example has been very helpful. If it's not too much trouble, I have tried to use the .TSC example with Tina, but I was having difficulty displaying the graph. Would you show me the setup that you used for the Transient? (Analysis >Transient > start Display = 0 > End display = 2uS) > click OK.)

Thanks,

0 Clemens Ladisch over 2 years ago in reply to Willer Justinvil

Guru 243910 points

Just opening the file and running Transient Analysis works for me. What exactly is your difficulty?

0 Willer Justinvil over 2 years ago in reply to Willer Justinvil

Prodigy 30 points

Thank you all. I got it.

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SN74LV244A: How check or verify the Buffer is damaged or not functioning