LT3091
Recommended for New Designs
The LT3091 is a 1.5A, low dropout negative linear regulator that is easily paralleled to increase output current or spread heat on surface mounted boards...
Datasheet
LT3091 on Analog.com
LT8333
Recommended for New Designs
The LT8333 is a current mode DC/DC converter with a 40V, 3A switch operating from a 2.8V to 40V input. With a unique single feedback pin architecture,...
Datasheet
LT8333 on Analog.com
I'm using the LT3091 to generate a negative voltage, and I'm using its current-limiting function to limit the current between 1 mA and 2 mA. Through the use of 10 Mega-ohm resistors (10 Mega-ohms for 2 mA, 20 Mega-Ohms for 1 mA) and a SPDT switch, I can switch between the 1 mA and 2 mA limit. However, in testing, it's not limiting the current to those set limits. Rather, when set to 1 mA, it outputs 7 mA before the output voltage drops while it outputs 8 mA when the switch is set to 2 mA. Why would this be occurring?
For more information, I'm using the LT8333 to generate -32 volts (as seen at the input of the LT3091), and the set output voltage is -30 volts. The voltage differential should be enough to handle the current I'm hoping for. There is a 1 Mega-ohm load to act as the minimum required load for proper voltage regulation.
The LT3091 itself is the 14-lead DFN package. Could there be issues with that package to cause it to behave that way? Would the 16-lead TSSOP package function any better?
