How can I simulate the transient response for LDO?

[Analog_starter]

Hi all,

I want to do the simulation for the LDO transient response, and who
can tell me how can do a step change of load currnet ?

Thanks & Best Regards
Analog_starter

 

[xwcwc1234]

For a load change current simulation , I usually use a switch with a current source at output node. So that I can use Hspice to control the switch on/off for load current change.

 

[Analog_starter]

But the switch will effect the load current value
Is the switch with very very big W/L ratio?

Best Regards
Analog_starter

 

[kawaiicat]

yeah, the W/L ratio is very big, the Iload is connect between the power mosfet to ground. Iload is a pwl so you define as a square wave

 

[sunking]

VPWL and VCVS

 

[Btrend]

u can use behavior model of switch as

 

[xwcwc1234]

I usually use behavioral model in Hspice for switchs as Btrend , so that the on resistance can be set to any value , and when off , it behave like open circuit. That's it .

 

[johnsmith101]

You can also use a PWL current source to step the output current.