SN74LVTH244A: SN74LVTH244A Error when using with XDS110 Debug Probe

Behtan Umut Mercan

Part Number: SN74LVTH244A
Other Parts Discussed in Thread: TMS320F28027,

Hello,

In my design my microcontroller is tms320f28027. Also I have a programming buffer SN74LVTH244A .

In order to program f28027, I use XDS110 debug probe. However, after few times of programing I encounter a damage at the buffer (SN74LVTH244A). I mean either one or two lines of buffer becames open circuit even if it supplied with 3.3 Voltage. (It happened more than 6 times)

What could be wrong?

Thank you in advance.

Sincerely,

over 1 year ago

0 Malcolm Lyn over 1 year ago

TI__Mastermind 28720 points

Hi Behtan,

Could you show a schematic picture so we can see how the microcontroller and debug probe are connecting to the buffer?

Best,

Malcolm

0 Behtan Umut Mercan over 1 year ago in reply to Malcolm Lyn

Prodigy 60 points

Hello Malcom,

I can share it on monday. Until monday if you have application circuit could you share it with me? I suspect that buffer absolete maximum voltage vcc and vio is small. Do you think xds110 debug probe damaged it? Also do you think should we use tvs or zeners to protect buffer?

0 Malcolm Lyn over 1 year ago in reply to Behtan Umut Mercan

TI__Mastermind 28720 points

Hi Behtan,

With no other information in regards to what the programming voltage is, input/output voltage of the buffer, schematic connections, etc. it's impossible to debug the issue or make any recommendations. It sounds like it could be getting damaged by the probe, but I don't have enough information.

Best,

Malcolm

0 Behtan Umut Mercan over 1 year ago in reply to Malcolm Lyn

Prodigy 60 points

Hello Malcom,

I have attached the schematics of microcontroller and buffer.

Sincerely,

Behtan Umut Mercan

0 Albert Xu1 over 1 year ago in reply to Behtan Umut Mercan

TI__Mastermind 41395 points

Hi Behtan,

Due to a US holiday, our team will respond back to your question tomorrow (Tues, 1/16)

0 Malcolm Lyn over 1 year ago in reply to Behtan Umut Mercan

TI__Mastermind 28720 points

Hi Behtan,

If I had to guess, probably the 1nF capacitor on the output of the buffer is too large and is sourcing too much current from the device. We recommend no larger than 75pF for most of our devices. Try reducing the size of the capacitor or adding a series resistor to limit the current.

Best,

Malcolm

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SN74LVTH244A: SN74LVTH244A Error when using with XDS110 Debug Probe