AD650: F/V converter from 0 to 2kHz

Document created by analog-archivist Employee on Feb 23, 2016
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Which values of resistors and capacitors may i use with an AD650JN
to make a F/V converter from 0 to 2kHz?


I recommend that you do not use the AD650 with a minimum input frequency of
0Hz. You should offset the input such that the minimum input frequency is at
least 100Hz.

Assuming an input frequency of 100Hz to 2100Hz.
Set tos to 460us, and choose Cos to be 63nF (68nF is a readily available value)
Assuming a 10V full-scale output, choose Rint to be 10kohm
Assuming a required response time of 1ms and accuracy of 8 bits, Cint is then
18nF (20nF is a readily available value)

The enclosed app note discusses how to choose components for given conditions.

If all you want is a controlled frequency source, consider using one of our
Direct Digital Synthesis parts. Take a look at the AD9830. Essentially this is
a digitally programmable oscillator.