This is the ldo_out when i used ideal current sour...
# analog-designm
Mustafa Ahmad
10/25/2021, 2:15 PMThis is the ldo_out when i used ideal current source (pulse varying from 0.1mA to 10mA) at the output why is the great difference between the 2 testbenches
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Luis Henrique Rodovalho
10/25/2021, 2:22 PMBoth simulations are ok. The difference is that the switched resistors results in an abrupt step. The ideal current source is not, considering that it is a ramp.
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Mustafa Ahmad
10/25/2021, 2:40 PM@User okay thanks ...which is better is it better to use ramp current source to avoid abrupt step caused after using switch ?
Mustafa Ahmad
10/25/2021, 2:41 PMI have a problem that i couldn't plot the current of the current source ..it gives error that no function is defined as i
Mustafa Ahmad
10/25/2021, 2:43 PMScreenshot from 2021-10-25 16-43-19.png
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Luis Henrique Rodovalho
10/25/2021, 2:48 PMAll those simulation results are good. None resulted in sustaining oscillation, just ringing. It means the LDO is stable and reasonably fast.
I'm just an researcher. The pros have lots of other specs to show. Look at this datasheet and their tests
https://www.ti.com/lit/ds/symlink/lp5907.pdf?ts=1635143762511&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FLP5907
Luis Henrique Rodovalho
10/25/2021, 2:49 PMYour simulation has a current source instance inside the control structure. It should be outside it, I think.
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Mustafa Ahmad
10/25/2021, 2:53 PMI put it outside the .control statement and i got the same problem also using ideal current source affects the other simulations rather than load transient
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Luis Henrique Rodovalho
10/25/2021, 3:05 PMMaybe you should also put a DC 0 statement in your IL instance, besides the PWL one, so it doesn't affect the other simulations.
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Mustafa Ahmad
10/25/2021, 3:21 PMokay i did this and it worked ..thanks
I want to verify that my testbench is correct that i measure the output at load of 0.1mA and at load of 1mA after waiting for settling time
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