TLV7022: Questions on Response Time to Noisy Pulses

Darren (FAE)

Part Number: TLV7022
Other Parts Discussed in Thread: TINA-TI

I am supporting an application using the TLV7022.
The application has seen some concerning behavior during system-level noise testing.
As we work through figuring this out, I need the following info.

1. What is the response time to a pulse of the TLV7022?
how wide does the pulse width have to be in order for the TLV7022 to respond?

2. Is there a parameter in the datasheet for this? Which parameter(s)?

3. Is there a comparator that won't respond to really short pulses (short being maybe IEC61000-4-x burst pulses)? Hopefully P2P?

The current application uses TLV7022 with <410kHz input signal.
Is there a solution/device that won't respond to pulses shorter than 2.4[us]?

Regards,
Darren

over 2 years ago

0 kai klaas69 over 2 years ago

Guru 140200 points

Hi Darren,

these burst pulses will always present a problem. Even if the comparator is slowly enough to not "respond" to the burst pulses, unwanted rectification effects in the input stage of comparator may take place resulting in very weird performance. Suited low pass filtering and the addition of hysteresis would be the best remedy.

Can you show a schematic and tell more about the application?

Kai

0 Darren (FAE) over 2 years ago in reply to kai klaas69

TI__Expert 5483 points

Hi Kai,

I appreciate the comment - I was hoping someone from the TI product line could reply.
I had some follow-up though that your post helped me consider.

Is there an effective way to add external hysterisis to TLV7022?
(Do you know of a good reference material with examples...?)

I did find this, but wondering if there was anything more specific to TLV7022...?
https://www.ti.com/lit/ug/tidu020a/tidu020a.pdf

0 Chi Nguyen1 over 2 years ago in reply to Darren (FAE)

TI__Genius 11701 points

Hi Darren,

We dont normally spec minimum pulse width with our low power comparators. As Kai mentioned, even with very narrow pulse widths, the comparator could not work properly and have weird distortions on the output and it would not perform according to electrical characteristics. Can you tell us more about your application with scope shots and schematic?

In the TLV7022 datasheet, there are examples of applying external hysteresis in the typical application sections

0 kai klaas69 over 2 years ago in reply to Darren (FAE)

Guru 140200 points

Hi Darren,

running a TINA-TI simulation is a good way to confirm the results of calculation.

Kai

0 Chi Nguyen1 over 2 years ago in reply to kai klaas69

TI__Genius 11701 points

Darren,

Please also tell us more about the pulses. How large are they swinging? Whats the duty cycle? What is on the output?

0 Chi Nguyen1 over 2 years ago in reply to Chi Nguyen1

TI__Genius 11701 points

Darren, we havent heard from you so I will be closing this post as we will be reaching the holidays in the next week.

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TLV7022: Questions on Response Time to Noisy Pulses