LDO simulation questions

[Shrouk Shafie]

Hey all , a question i couldn't find an answer for :
In simulating LDO to get LINE regulation , shall the load be only a capacitor or shall I insert a DC current source?

Thanks.
Shrouk.

 

[lanreayo]

Line regulation is defined as the stability of your LDO output with respect to variations in the INPUT....So its defined as Delta Vout / Delta Vin. If your LDO is supposed to drive a current load, then ofcourse! If not you only need to put a current load if you want to measure the Load Regulation ( Delta Vout / Delta Iload ). Please still verify from experts that this is right....I am currently working on an LDO too. All the best.

 

[Shrouk Shafie]

Yeah it should supply current. Am just a bit confused with simulations.
Thanks.

 

[dick_freebird]

A DC PSRR for datasheet purposes may be at one condition
but for design integrity you need to hit the corners of the
"box" - min and max DC load, at least.

A HF PSRR requirement will also want you to box the filter
capacitance, probably line voltage as well (to see how the
control loop may respond to desaturating something in the
error amp, at low voltage, or failing to fully choke the pass
FET off at high line low load, for example).