I’ve no clue what the origin story on this particular item is, other than that it was added to our listings roughly a year ago, to all appearances as a regular production, standard item available to anybody. All parts eventually go obsolete, and sometimes somebody will come in and buy up whatever stock we have on a given P/N. So yes, there’s always some risk of not being able to obtain product on short notice. Our sales folks can work with you to set up scheduled orders, if you’d care to hedge your bets on that front.
But this is a 40mm fan of which we speak, and those are not uncommon; we have other listings for products of a similar general profile here. 12V versions appear to be somewhat more numerous, as higher rotational speeds generally require higher input voltages and it’s more common for folks to be concerned with getting enough airflow to do a job, than being able to to throttle down to near-nothing.
Many potential points of discussion arise herein, but the question of instantaneous versus average values seems to be one of significance. Yes, charging even small capacitances rapidly can require fairly high instantaneous currents for short periods. Yes, an nRF52840’s limited drive capacity will probably distort things somewhat. But does it really matter? If so, why? Filling a 1nF bucket to the 5V line and dumping it out 25K times a second takes 125uA on average, which isn’t much compared to the supply current. And that 100mA “maximum” figure? It might not mean what you think.
Such a specification does not strike me as particularly common insofar as it’s a thing that will change over the life of the fan as the bearing system degrades, and given the device’s purpose as an air mover, spending extensive time characterizing how closely one can operate to the point of not moving air seems to be an exercise of limited practical utility.
That it is, offered for purposes of comparison with the similar housing indicated in the fan datasheet. Compatible contacts and mating board-side connectors are, as mentioned, linked under the “Associated Product” and “Mating product” headlines further down the product page.