Hello,
I need to know about constant current source whose output impedence should be 1000 Mohm or more,which source less than 100 micro amp current constantly irrespective of load.
I used REF200IC earlier to get 50 micro amps constant current .Since its output impedence is upto 100 Mohm only,it willnot provide constant current for certain load .
ie, for 5K ohm load,REF200 gives 49.9975 micro amps
for 10K ohm load,REF200 gives 49.9950 micro amps
for 12K ohm load,REF200 gives 49.9940 micro amps
You can see the third decimal place is varying.If output impedence is high, i think we can improve stability further more.
if i get a constant current source with 0.0001 stability,its much helpful to me.
Please suggest proper IC to me as quick as possible so that i can buy it from Texas.