Hello everybody,
I’m in need of a programmable, precise and low noise DC current source capable of sourcing up to 3A DC at 9V DC. For that I designed a current source made of 3 parallel LT3080 for rough tuning and one parallel LT3092 for fine tuning, to add the currents together at the output. For the Rset and Rout I use digital potentiometers and a 1 Ohm resistor with a tolerance of 1% or better and low temperature drift. In the datasheet of the LT3092 there is a sub chapter about quieting the noise and it says to put a Cset parallel to Rset and also reduce the output current noise by putting a high C between the output and GND. Is it possible to still maintain stability if I use big electrolyte capacitors (C=4700uF maybe even multiple 4700uF, all low ESR<50mOhm)? For my system cost or size is no concern. Have you done tests with big C values? Is stability more important than high C to GND because of the inherent regulation of the LT3080 and LT3092?
This is the setup I use for both LT3080 and LT3092.
The input voltage is sourced by a lab DC source.
Do you have other ideas or tips for me?
What would you recommend for a precise and low noise DC current source?
Thank you in advance!
Best regards,
Max