I'm working on a dac which use a Te7022 as usb receiver, it will be powered by the mic5205 LDO so I search for articles about stability with LDO and got this: http://www.ti.com/lit/an/snva167a/snva167a.pdf. It's quite easy to understand until section 7 "Additional Poles From Ceramic “Bypass” Capacitors". I think the author forgot to include the Esr of the bypass capacitor in the equation.A single 0.1uf X7R capacitor will often have an esr about 20mohm so 10 capacitors in parallel is effectively about 3mohm and it's also parallel with the tantalum so isn't Rout in the equation 3mohm instead of 0.43ohm?
Electrical – LDO regulator stability with bypass capacitor
bypassbypass-capacitorstabilityvoltage-regulator
Related Topic
- ESR and CSR of Capacitor
- Electronic – Will a LDO regulator with a proper output capacitor be destabilized by the addition of a high-ESR capacitor
- Electronic – MLCC vs Tantalum: For Decoupling, input to regulator and ripple reduction
- Electronic – Choosing capacitors for a linear voltage regulator
- Electronic – LDO Output Capacitor Selection and ESR Consideration
- Electronic – Tantalum capacitor as bypass for digital IC
- Electrical – lum – LDO with tantalums and circuit with ceramic bypass capacitors
Best Answer
MIC5205 using 1nF bypass cap can be modelled by a 0.01R resistor in series with an inductor of value 0.6 ... 1.5 µH (it depends on DC current).
Using these parameters, you can simulate its stability with the ESR of your tantalum caps. Set the transition from regulator to cap below 40 kHz to avoid the regulators' second pole.