Hi all,

What is the input impedance (ohm||pF) of the AD8627?

I'm using the AD820 now but I would like to find alternative parts. The AD820 data sheet shows imput impedance spec

but AD8627 does not.

Regards,

Kazu

Hi all,

What is the input impedance (ohm||pF) of the AD8627?

I'm using the AD820 now but I would like to find alternative parts. The AD820 data sheet shows imput impedance spec

but AD8627 does not.

Regards,

Kazu

Hi Kazu,

AD8627 is a JFET input amplifier which typically have very high input impedance (Giga to Tera ohms) and very low input bias current in pA range. Because of this, it is more common for us to measure input bias current rather than the input impedance for a high impedance device like a JFET amplifier. Looking at Figure 9 Input bias current vs VCM of AD8627 datasheet, we can estimate the input impedance by dividing VCM by Ibias which is in Tera ohms range.

Hi Kazu,

There is no data regarding input capacitance but probably it would be around 10pF or less.