ISO124: accuracy calculation

Zhenyu

Part Number: ISO124

Hello,

I am calculating the iso amp output error range. Can you advise if the following calculation is correct?

output voltage Vo = (Gain +/- Gain_error + Gain_error_temp)*(Vin +/- Vos)*(1+/- NL). Vos is input offset voltage. NL is nonlinearity.

If the input is 2Vdc, then the max possible output at 85C is ( using ISO124 spec): Vo_max = (1+0.5%+10E-6*(85-25))*(2+0.05)*(1+0.01%) = 2.062 V.

Let's don't consider the Vos temperature variation for now.

Thanks.

Zhenyu

over 8 years ago

0 Tom Hendrick over 8 years ago

TI__Guru**** 181751 points

Hi Zhenyu,

I'll go over your calculation numbers on Monday. I am curious to know though, is this a new project or an existing project? We will have a newer version of the ISO124 coming out later this year that you might be interested in.

0 Zhenyu over 8 years ago in reply to Tom Hendrick

Prodigy 140 points

Hi Tom,

It is for a new project. I look forward to a new version of ISO124. I want to control the error range of the overall signal chain to be within +/- 2.5% in temperature range of -40C ~ +85C. The error range of the iso amp stage better to be within +/-1%. So it's preferable that the iso amp has an input offset voltage within 10mV.

Thanks.

Zhenyu

0 Tom Hendrick over 8 years ago in reply to Zhenyu

TI__Guru**** 181751 points

Hi Zhenyu,

If it's OK with you, I'll send you a direct e-mail to the account your used with your My-TI profile to discuss some alternate possibilities to the ISO124.

0 Zhenyu over 8 years ago in reply to Tom Hendrick

Prodigy 140 points

Hi Tom,

It's ok. I welcome the discussion.

Thanks.

Zhenyu

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ISO124: accuracy calculation