NOW WITH THE O- TO 10VDC ADJ RANGE WHAT HAS TO BE CHANGED TO GET THE 400HZ FREQ OUT
AND MAKE IT STABLE WITH LITTLE DRIFT IN FREQ. I WILL BE USING POLYSTYRENE CAPACITORS
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NOW WITH THE O- TO 10VDC ADJ RANGE WHAT HAS TO BE CHANGED TO GET THE 400HZ FREQ OUT
AND MAKE IT STABLE WITH LITTLE DRIFT IN FREQ. I WILL BE USING POLYSTYRENE CAPACITORS
Hi Willie,
Thanks for your post. Our engineer responsible for this device is out of office on Holiday break. Please excuse the delay, we will support you soon.
YES I WOULD LIKE TO ADJ THE DC VOLTAGE TO THE PART SO SO I GET A 400HZ SQ. WAVE OUT OF THE PART
I WILL BE USEING A VOLTAGE REF AS THE ADJ VOLTAGE SO THE OUTPUT STAYS STABLE OVER TEMP AND TIME
Hi Willie,
For C2 take a cap with very low dielectric absorption:
This table can be found here:
I would take a PS cap like this one:
Or an encapsulated PP cap like this one:
For C2 only the dielectric absorption and the leakage current is of interest. Then PS and PP is the best dielectric material and the true film types should be favoured over the metallized film types.
But when it comes to temperature drift and long term drift C0G(NP0) should be prefered:
So for C1 I would choose a C0G(NP0) cap, best with low manufacturing tolerance.
Later more...
Kai
Hi Willie,
figure 2 of datasheet of VFC32 shows what cap values have to be chosen, if you want to reduce the full scale frequency down to 1kHz or even below. However, this will result in cap values which might be unsuitedly large and difficult to obtain.
A remedy is to add a digital frequency divider to the output of VFC32. You could take the CD4024 which has a Schmitt trigger clock input. The CD4024 is fast enough to be able to handle the frequencies of interest but is, at the same time, slow enough to keep the switching noise low.
Kai
OKAY I'VE FIGURED IT OUT NOW ,NOW I SEE HOW THE PART WORKS ,WHICH IS MUCH BETTER THAN THE OTHER VF-FV CONVERTER ICS OUT THERE
THANKS
YOU CAN CLOSE THE CASE