TPS73201-EP: LDO slow turn-on circuit

Hi Federico,

The easiest thing would be to see if you could use one of the fixed output voltage versions, this would give you access to an NR pin and would allow you to add a capacitor from NR to GND to both lower the output noise and reduce the startup time.

Unfortunately if you are using the adjustable version and cannot switch to a fixed output version, then you won't have access to the reference in order to slow it down. In this case you could add a Cfb in series with the top resistor in the voltage divider, this is sometimes referred to as a feed forward capacitor. This will AC couple Vout to FB and will result in a slower startup time. We have an app note discussing the pros and cons of using a feed forward cap and section 2.1 includes the way to estimate the startup time based on the capacitor and resistors used and also includes some example scope shots. It is important to note that since the reference isn't actually being slowed down the initial dV/dt of the startup curve will remain unchanged.