[MOVED]how to make an LDO with 3.6V output from 4~5V input?

[allennlowaton]

hello guys..
Is it possible to make an LDO with an output of 3.6V from a 4~5V input?
I have done an LDO before but that was with a fixed input.
I want to try this time with a varying input.

Thanks..

 

[alexan_e]

Re: how to make an LDO with 3.6V output from 4~5V input?

sure but depending on the LDO used you need to have the a minimum input-output voltage difference
For example LM1117 has fixed voltage versions and a variable version, the voltage drop in the datasheet is about 1.2v so for 3.6v output you need 4.8v input
You can probably find other LDO with lower minimum in/out voltage drop.

**broken link removed**

Alex

 

[allennlowaton]

Re: how to make an LDO with 3.6V output from 4~5V input?

thanks.
I will put the LDO on chip. 1.2V drop out is unacceptable in my application.
100mV to 200MV dropout is what I need.

 

[keith1200rs]

Re: how to make an LDO with 3.6V output from 4~5V input?

I assume you are designing an IC (in which case this thread is in the wrong forum). It is perfectly possible to design a regulator with a variable input - that is the normal case. If you have already designed an LDO I don't know why you are concerned about a variable input. You simply need to ensure the devices used can work at the input voltage.

Keith

 

[allennlowaton]

Re: how to make an LDO with 3.6V output from 4~5V input?

thanks for the reminder, keith...
I always made the mistake of posting here about IC. It should be on the other forum.

 

[Sudarsan_EDA]

Re: how to make an LDO with 3.6V output from 4~5V input?

Usually Dropout voltage calculated with respect to current output of the device.
If you required High current output proportionally dropout voltage also increases.
You are not designing an ASIC IC you can choose TPS73133DBVT which is from texas instr.,

 

[keith1200rs]

Re: how to make an LDO with 3.6V output from 4~5V input?

thanks for the reminder, keith...
I always made the mistake of posting here about IC. It should be on the other forum.

I will move it.

Keith.

 

[allennlowaton]

Re: how to make an LDO with 3.6V output from 4~5V input?

I will move it.

Keith.

thank you keith..