[sdiy] A question about regulator noise figures

[Tom Wiltshire]

I also notice now that I’d missed that the figure given is actually 8uV / sqrt(Hz), which they’ve expressed as uV/(Hz)1/2

I assumed the superscript referred to the notes under the table (which is Microchip’s usual style, to be fair), but that’s not what’s going on here - it’s an exponent.

==================
       Electric Druid
Synth & Stompbox DIY
==================



> On 16 Mar 2021, at 00:29, Tom Wiltshire <tom at electricdruid.net> wrote:
> 
> Aah! OK, thanks Brian. Yes, flicker noise I know about, but I hadn’t made the connection.
> 
> I still don’t understand the units though. How could I convert a flicker noise measurement like 8uV/Hz to a RMS measurement across a given bandwidth like the other data sheets offer? Is that even possible? I’m starting to suspect some manufacturers don’t *want* me to be able to compare specs with their competitors! ;)
> 
> Tom 
> 
> ==================
>       Electric Druid
> Synth & Stompbox DIY
> ==================
> 
> 
> 
>> On 16 Mar 2021, at 00:05, Brian Willoughby <brianw at audiobanshee.com> wrote:
>> 
>> Look up the tern, 1/f noise, a.k.a. Flicker noise.
>> 
>> That sort of noise seems to be reported in V/Hz. In this case, it's µV/Hz.
>> 
>> https://en.wikipedia.org/wiki/Flicker_noise
>> 
>> Brian
>> 
>> 
>> On Mar 15, 2021, at 16:57, Tom Wiltshire wrote:
>>> Hi All,
>>> 
>>> I’ve been reading data sheets for linear regulators, and I’ve got a question.
>>> 
>>> Some regulators specific the output noise voltage from 10Hz to 100KHz as an RMS level, usually uV. However, the Microchip MCP1702 specifies an output noise figure as 8 uV/Hz. What does this mean? What’s the relationship between uV/Hz and RMS uV?
>>> 
>>> Here’s the datasheet:
>>> 
>>> https://4donline.ihs.com/images/VipMasterIC/IC/MCHP/MCHPS03366/MCHPS03366-1.pdf?hkey=6D3A4C79FDBF58556ACFDE234799DDF0
>>> 
>>> Thanks for any guidance!
>>> 
>>> Tom
>> 
> 

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