TS12A12511 Logic Level High Input Minimum Threshold Vih

Feller Murray

Other Parts Discussed in Thread: TS12A12511

The TS12A12511 features a 5V logic level input suggesting that it will operate from signals having a nominal 0 to 5V swing typical of logic circuits supplied from 5V regulated sources. However, the regulators for those circuits have tolerances on their output voltages which could result in the supply voltages being under 5V. There would then be uncertainty as to whether the switch would operate when it is supplied with 12V since its upper limit switch threshold is then specified at 5V. Is the specification in error? Should the upper limit threshold be something under 5V so that a 5V input signal will ALWAYS WORK WITH ALL OF THE PARTS?

over 8 years ago

0 Adam Torma over 8 years ago

TI__Mastermind 45380 points

It looks like the datasheet spec may have been conservative in stopping at Vih min of 5V.

I looked through some of the characterization data we have and it looks like there some margin based on the three units tested. Vih min of 5V +/- 10% with a 12 V supply sounds reasonable.

Thank you,

Adam

0 Feller Murray over 8 years ago in reply to Adam Torma

Prodigy 55 points

Hi Adam:
Not every switch will operate with a 5V +/-10% logic level input and a 12V supply according to the data sheet. How do you resolve this?
Murray

0 Adam Torma over 8 years ago in reply to Feller Murray

TI__Mastermind 45380 points

Murray,

What would you like to have resolved to give you confidence to use this device in your system? Based on the testing of a couple of devices above it looks like the Vih min value is well below 5V without much variation even across full temperature range.

Looking forward to your reply,
Adam

0 Feller Murray over 8 years ago in reply to Feller Murray

Prodigy 55 points

Hi Adam:
This is the issue: If the parts that I receive from TI are at the high limit of the spec (approaching 5V), they will still be considered good parts by TI even though they do not consistently operate with nominal 5V logic signals. The spec sheet should be changed to 3.5V for example and the parts tested accordingly so that every part then meeting the spec will work.
Murray

0 Adam Torma over 8 years ago in reply to Feller Murray

TI__Mastermind 45380 points

I understand you comment and will look to see if our team will be up to the task in re specifying the device parameter.

0 Feller Murray over 8 years ago in reply to Adam Torma

Prodigy 55 points

This is a big issue for a production design-making sure that it always works. Please let me know the results of your request. Thanks, Murray

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TS12A12511 Logic Level High Input Minimum Threshold Vih