snowblind
Newbie level 1
Hello,
I would like to find or build an analog signal multiplexer to serve as the front-end to an ultra-low bias current op-amp, for example the LMP7721. This amp has 3fA typical, 20fA max input bias current. This is the lowest amp I've found, but there are several other amps that are within 10X higher.
However, I am having a really hard time finding analog switches with comparable leakage, although one could presumably be made using jfet switches and jfet PADs to keep them from blowing up.
The lowest leakage mux I've found is the ADG658. At 25C the off leakage is 5pA typical. This is a CMOS-based mux. I did find a JFET mux, the analog devices MUX08, with 10pA typical leakage.
I have considered building my own mux using low leakage JFET, such as the 2N4117. However, the 2N4117 is rather large and it seems that some manufactures are discontinuing this design so I am nervous about incorporating it into mine.
Does anyone know of an analog multiplexer (or even a switch), with guaranteed leakage < 1pA (for below 50C)? I would also really appreciate an ideas for discreet jfet components to make my own mux.
thanks
I would like to find or build an analog signal multiplexer to serve as the front-end to an ultra-low bias current op-amp, for example the LMP7721. This amp has 3fA typical, 20fA max input bias current. This is the lowest amp I've found, but there are several other amps that are within 10X higher.
However, I am having a really hard time finding analog switches with comparable leakage, although one could presumably be made using jfet switches and jfet PADs to keep them from blowing up.
The lowest leakage mux I've found is the ADG658. At 25C the off leakage is 5pA typical. This is a CMOS-based mux. I did find a JFET mux, the analog devices MUX08, with 10pA typical leakage.
I have considered building my own mux using low leakage JFET, such as the 2N4117. However, the 2N4117 is rather large and it seems that some manufactures are discontinuing this design so I am nervous about incorporating it into mine.
Does anyone know of an analog multiplexer (or even a switch), with guaranteed leakage < 1pA (for below 50C)? I would also really appreciate an ideas for discreet jfet components to make my own mux.
thanks