VCA810 Can’t Magnify

[ethiopia]

Hello~all
Recently I am involving in a project about VCA810(this is its data-sheet: http://www.kynix.com/uploadfiles/pdf9675/VCA810AID.pdf ). I met some troubles and I hope someone here can help me out.
My schematic diagram is given below. Please have a look whether there are some wrongs. Thank you in advance.

My VCA810 can realize the attenuation of -40DB when the controlling voltage is between -1V and 0V. However when the voltage is between -1V and -2V, it can’t magnify and there are no signals.
How to solve such problems? Can you?
Best wishes~

[PietroBaima]

Hello and welcome onboard.

Unfortunately your image is not reachable, hence I am afraid it will be hard for you getting an answer.

Can you please fix the attachment for me?

Thanks

[simo85]

Ops, Pietro, I attached the image while you were writing your message.
I didn't see it. Sorry.

Maybe the OP will start use Fidocadj next time.

[PietroBaima]

No worries, indeed, thanks!

[boiler]

According to your schematic, you swapped the positive and the negative supply.

Cheers, Boiler

[lelerelele]

Hi ethiopia
Sorry in advance for my bad english!

I not know this IC, but try to make a solution.

Why input signal on +input? this are offset? if this offset are 1mV (for example) what are the +40dB output of this?
said this, output pin can saturate? What are voltage Dc out of this?

for me problem can here.

bye.

[MarcoD]

Dear ethiopia,
your electric drawing appears to be correct referring to the data sheet.
How do you set the Vcontrol ? In figure 47 they advise to insert an RC lowpass filter, but it is not mandatory.
About the Vc I have understood:
VC = 0 V -40 dB attenuation X100
VC = -1 V 0 dB gain X1
VC = -2 V 40 dB gain X100

ciao

[boiler]

your electric drawing appears to be correct referring to the data sheet.

No, it doesn't:

Cheers, Boiler

[boiler]

Another question: why are you talking about the VCA810 while your schematic is built around a VCA821?