Theoretical and practical measurements

UM1737

10/14

DocID025983 Rev 1

Equation 7

When:

Rf/Rg << AVD

Example:

Rf/Rg = 470

AVD = 120 dB (the minimum value for the TSZ121)

Clearly, the higher the gain of the schematics, the higher the inaccuracy, but in this

case the error is negligible.

Vout

Rs

I

×

----------------

Rf

Rg

--------

1

1

Rf

Rg

--------

+

AVD

------------------

+

---------------------------

=

Vout

Rs

I

×

----------------

Rf

Rg

--------

1

ε

+

------------

Rf

Rg

--------

1

ε

–

()

≈

=

Error %

()

1

Rf

Rg

--------

+

AVD

------------------

100

×

–

=

Error

1

Rf

Rg

--------

+

AVD

------------------

–

100

×

0.047%

–

==