Originally Posted by Citizen86
2. Are the alternatives of the TPS Regs, you think they are comparable quality, or is it worth it to spend 3x the price on the REGS used originally?
These selected regulators seem to best REG101 in almost every specification, and they're considerably cheaper. They have better ripple rejection, especially at HF, and lower output noise. Just be careful with them, since the max input voltage is only 5.5V. I see no reason to want the REG101 other than for higher voltage input - but since the TPS793xx uses a standard SOT23 regulator pinout, you can substitute the REG101 or just about any other SOT23 regulator you want.
I missed them on my last 'regulator search' somehow. I don't know what it is about TI's site but I always seem to miss perfect parts when I search for things there.
I have been using LP2985 lately myself with good success, and I think I'll switch to these - they seem to spec better and they're a few cents cheaper. If you wanted to use something else, LP2985 make a good substitute as well - it's what's used on the Opus DAC which seems to have a good reputation. It also has a high-ish input max of 16V (REG101 is 10V, TPS793xx is 5.5V), which I have made use of to power directly from my bipolar 15V supply. But really I would stick to the TPS793xx, or if you must, the REG101, since this board is not set up to handle external power anyway.cetoole/tombI know you mentioned it earlier in the thread, but in the interest of flexibility maybe it is worth adding a header and jumper to allow external power?
Actually, nevermind, you're right. It'd be tricky to add to your layout, and really you should have the logic gate to disable the chip when USB power is not connected anyway, which isn't appropriate to add here.