SN74LV123A-Q1: SN74LV123A-Q1 error and offset at triple temperature

Josh Wei

Part Number: SN74LV123A-Q1
Other Parts Discussed in Thread: SN74LVC1G123

Tool/software:

Hi Team,

I have searched related answers but it seems not accurate enough to solve these questions. Please help with these questions below:

[Q1]The three-temperature accuracy of the tw parameter in SN74LV123A-Q1 is 10%. Has the three-temperature error and accuracy of the Cext capacitor been considered?

[Q2] What factors on the chip side cause such a large tw error of the chip?

[Q3] Under ideal conditions, what is the tw error range of the device under three temperatures (only considering VCC power supply of 5V)?

[Q4] If R=150kΩ, C=30nF, is there any risk in this application condition? (There is no way to make the resistor so large. The capacitor is selected with 2% accuracy of COG, and the maximum capacitance can only be 10nF)

https://e2e.ti.com/support/logic-group/logic/f/logic-forum/579570/sn74lv123a-tw-output-pulse-duration-at-ta--30c---0c---25c?tisearch=e2e-sitesearch&keymatch=SN74LV123A-Q1%2520tw

Thanks!

3 months ago

+1 Malcolm Lyn 3 months ago

TI__Mastermind 19090 points

Hello Josh,

No. When the temperature testing is done, the device is isolated from all external components, so the Cext temperature remains the same throughout the testing.
Simply process variations and changes in internal capacitances and just the nature of the design. These work off of RC constants and are not designed to be precision instruments.
Please refer to the graph from the datasheet:
There is nothing wrong with this RC value.

If temperature variation is a big concern, please consider the SN74LVC1G123 instead. This device has more robust temperature performance, with about 1% variation over the total temperature range: