FA64S input range

Hi,
I am using your FA64S + USBME64 system to process MEA signals..
In the datasheet of your FA64S I read that the input range is +/- 500 mV (with respect to 5V power supply).
Could you tell me the range for a 6 V power supply, which is actually the one I am providing with your PS40W?

Sometimes I see no signals on MC_Rack (i.e., flat traces, with really really small noise)..Could this due to the fact that inputs to FA64 are not included in its input range?

Thank you!!
Greetings

Holly

Dear Holly,
the supply voltage is irrelevant in that respect. The GA64S has an internal voltage controller set to 5V. Divide these 5V by the combined amplification of the FA itself, and any preamplifiers before, then you know what the maximal signal size can be. A flat line in MC_Rack might indeed be caused by an out of range signal.

Best regards Frank

Thank you,
so, if i understood correctly, the value of input range reported in the FA64S datasheet (i.e., +/- 500 mV, i.e., so that the output of fa64s does not saturate) is obtained dividing 5V by 10, i.e., supposing a gain of FA64S equal to 10?
greetings

Dear Holly,
that's right. I agree these 500mV are a bit misleading. In fact, we'll replace this by something like "maximal signal size after all amplification steps".

Best Frank

Ok, thanks!!
And a last thing for my clarity :-)

So, an input to FA64 could me more than 500 mV in amplitude but in this case I will se a saturation of the output.

I guess that the maximum input "physically" allowed to enter the fa64 must be lower than the power supply range of the fa64, i.e. 5 V..right?

Frank MCS wrote:A flat line in MC_Rack might indeed be caused by an out of range signal.

So, with "out of range" do you mean for example a sinusoidal wave with an offset of 10 V with respect to the ground of the system? So, a signal which is totally above 5 V or below -5 V at the input of fa64, right?

Thanks

Hi Holly,
yes, but the BC headstage amplifier also often shows a flat line for a while after inserting a new MEA, especially for noisy or drifting or out of range channels.

Frank