It's power filtering. Yes the engineer had something in mind with their 3.3uH, but going with 22uH shouldn't make too big of a difference. If that one is easy to obtain for you, go for it!

I would still try to match the original value, or at least close to it. Small inductors have poor DC resistance with higher inductance values, also a lower maximum current limit that you need to stay below. If that chip it's powering consumes 135 mA, you could already be at or above the allowed limit for a 22 uH inductor according to the datasheet you linked (85 mA, 150 mA for the smaller packages).

tehsiggi wrote on Today, 03:56:

It's power filtering. Yes the engineer had something in mind with their 3.3uH, but going with 22uH shouldn't make too big of a difference. If that one is easy to obtain for you, go for it!

asdf53 wrote on Today, 05:47:

I would still try to match the original value, or at least close to it. Small inductors have poor DC resistance with higher inductance values, also a lower maximum current limit that you need to stay below. If that chip it's powering consumes 135 mA, you could already be at or above the allowed limit for a 22 uH inductor according to the datasheet you linked (85 mA, 150 mA for the smaller packages).

Therefore, voltage drop in low-current signal circuits is usually unimportant, while at low frequencies, the CMRR and PSRR reach their maximum.
In real life, using inductors for filtering in powering of small-signal circuits is a very bad idea. The result is a resonant system, which leads to increased noise at certain frequencies.
There should always be a lossy component—a high-ESR capacitor (or a RC snubber circuit) and, preferably, a parallel resistor to suppress the quality factor of inductance.
A ferrite bead is so-so. It's the worst combination of inductor and resistor, but it's inexpensive and practical.

So, it's unclear what ATI engineers were thinking, but don't get carried away with inductance.
On the one hand, you'll never use "ATI theater."
But if you suddenly want to digitize VHS, these inductances can cause, for example, vertical stripe interference (due to resonance in the ADC power supply circuit).