LMK1C1108: slew rate on the limit

Andreas Glatz

Part Number: LMK1C1108

I have a design with 1.8V supply where the input is a 25MHz clipped sine. The V_IL, V_IH and the negative slew rate are within specification but the positive slew rate is just outside with 0.07 V/ns. It seems to work nicely anyway so I wonder what is the potential effect or risk of this? We are for example limited to a temperature span of -40C to + 85C.

4 months ago

0 William Pfennigwerth 4 months ago

TI__Expert 6931 points

Andreas,

The apps engineer who supports your question is out of office and will reply to you on Monday.

Regards,

Will

0 Andrea Vallenilla 4 months ago in reply to William Pfennigwerth

TI__Genius 10045 points

Hello Andreas,

With slow slew rate, there is increased risk for glitches on the output clock. There isn't hysteresis on the input. If there's significant noise on the input, the part may glitch. The 0.1 V/ns is just what we simulated/tested. I'm assuming your input may be clean enough that is not causing any problems, but that may not be the case at more extreme temperatures. Let me know if you need anything else.

Good Luck,

Andrea

0 Andreas Glatz 4 months ago in reply to Andrea Vallenilla

Prodigy 50 points

It looks like this in room temperature. Which temperature extreme do you expect to be worst case?

0 Andrea Vallenilla 4 months ago in reply to Andreas Glatz

TI__Genius 10045 points

Andreas,

We have only characterized for the specified temperature range of -40°C to 125°C for 0.1V/ns slew rate; therefore, I do not have the data to tell you whether or not it will not behave as expected. This includes whether is supposed to operate worse at extreme cold or extreme heat, either way the part can lead to unwanted behavior.

Also, what's the volume of this project and the project name? Let me know if you need anything else!

Best,

Andrea

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LMK1C1108: slew rate on the limit