Power supply for module with MAX31856?

[Javert]

I am working on a PCB for a module with 2 to 4 pcs of 19 bit converters for thermocouples MAX31856.
The module will be connected to the processor with an approx. 30 cm cable.
The cheapest and easiest way is to power the entire module from a 3.3V LDO that powers the MCU.
On the module, several SMD C and possibly also SMD induction for noise shielding
On the other hand, I believe that a 19-bit ADC and an amplifier for thermocouples is a hell of a sensitive thing and a better solution is to supply the module with +5.0V and put your own low-noise LDO at 3.3V on the module.
Can anyone guess whether it makes sense to place a separate LDO on the board with the converters?

Thanks

 

[KlausST]

Hi,

My personal opinion: thermocouple and 1/1000 of °C measurement makes no sense at all. So you won´t get meaningful values down to 19 bit.

But a separate regulator won´t hurt.

Klaus

 

[D.A.(Tony)Stewart]

With a PSR sensitivity of 0.4 ‘C/ V it won’t matter.

 

[Javert]

Thank you for the responses.
You're probably right, one extra LDO won't hurt anything
I can only think of what if only +3.3V is available?
Do you have an idea how, for example, the LP2985 3.3V behaves when it has a 3.3V or 3.22V input?
Yes, it doesn't stabilize, I'm concerned with whether the voltage at the output will be at the input minus the losses on the transistor or nothing or how and when, etc.