I'm building a DAC and I'm looking for some advice on power supplies. I noticed that some designs focus on using very low noise LDOs. Is there really a noticeable difference vs using jellybean LDOs with proper decoupling? Which characteristic of LDOs is more important (RMS noise, PSRR etc)?
I think for a DAC low noise and low output impedance is the main requirement.
LDO is not that important, unless you have an issue with the input supply voltage.
Jan
LDO is not that important, unless you have an issue with the input supply voltage.
Jan
It seems that LDO (Low-dropout) has become a synonym for regulator 😉
Power supply requirements are dependent on the DAC chip. Low output impedance benefits most if not all DAC chips. Older 16/20 bit DAC chips do not necessarily benefit from ultra-low noise regulators. With delta-sigma DAC chips to reach datasheet performance ultra-low noise regulators are needed but typically only for critical supplies (voltage reference).
LDO (low-dropout) regulators are especially useful for DAC chips operating at lower voltages. E.g. for using 5V input to power a 3.3V DAC chip.
Power supply requirements are dependent on the DAC chip. Low output impedance benefits most if not all DAC chips. Older 16/20 bit DAC chips do not necessarily benefit from ultra-low noise regulators. With delta-sigma DAC chips to reach datasheet performance ultra-low noise regulators are needed but typically only for critical supplies (voltage reference).
LDO (low-dropout) regulators are especially useful for DAC chips operating at lower voltages. E.g. for using 5V input to power a 3.3V DAC chip.
I guess LDOs are the industry standard now for modern regulators?
The DAC only asks for a low output impedance regulator. I've used jellybean 78xx/79xx regulators in all my analog designs without any issues, sometimes even switching regulators. But I've never built a DAC.
The DAC only asks for a low output impedance regulator. I've used jellybean 78xx/79xx regulators in all my analog designs without any issues, sometimes even switching regulators. But I've never built a DAC.