OPT101: OPT101 setting question

kerr chang

Part Number: OPT101

Hi Team

Ask some questions about OPT101.
In terms of circuit diagram, The REXT = 1M ohm and CEXT OPEN
.
The waveform is measuring gray scale 0 -> 128 -> 256.
If I want to increase the gap between each step, Is it increase REXT?

At the same time, if I want to improve the rise time, what do I need to do?

if I set the speed of the 1st order of the gray scale 0~255 steps, how long does each level have to be set before it will affect the judgment of this IC?

over 6 years ago

0 Alex Bhandari-Young over 6 years ago

TI__Mastermind 25895 points

Hi Kerr,

Thanks for your question. I will get back on this after the holidays.

Best,

Alex

0 kerr chang over 6 years ago in reply to Alex Bhandari-Young

Genius 4075 points

Hi Alex

Did you have any updata for this issue ? Thank you so much!!

0 Alex Bhandari-Young over 6 years ago in reply to kerr chang

TI__Mastermind 25895 points

Hi Kerr,

Sorry for the delay posting back here with the holidays. Yes, increasing Rext will increase the gain of the amplifier. This is what you are asking, correct? Also if you see Table 2. in the datasheet it shows this effect of changing Rext.

Best,

Alex

0 Wayne Wu over 6 years ago in reply to Alex Bhandari-Young

Prodigy 10 points

Hi Alex,

I have a question. Please check the waveform between two vertical lines. In the first few seconds (about 15 ms), the waveform is lower than other part. How to improve it? (Improve rising time?)

Regards,
Wayne

0 Alex Bhandari-Young over 6 years ago in reply to Wayne Wu

TI__Mastermind 25895 points

Hi Wayne,

In the datasheet 8.3.2 Feedback Network and Dynamic Response gives a formula for rise time based on bandwidth. Bandwidth will depend on the R and C used in your circuit so you can try changing these to improve the rise time. Depending on if you can decrease the gain used for your application you may or may not be able to improve this.

Best,

Alex

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OPT101: OPT101 setting question