Conductive Polymer Aluminum Solid Capacitor -vs- MLC Capacitors in HV LDO

[beaker353]

I'm working on a little power supply'ish project that keeps on getting pushed onto the "back burner" and then brought back to the "front burner" when time becomes available. In the project I'm using a Linear LT3086 high voltage LDO that has programmable current limit and  parallel capabilities. Pretty slick little (literally) unit. In the docs it specs 10uF bypass caps on the output and input to maintain stability. It specifically says you CAN you ceramics, but not that you NEED to. As I'm running this pretty high voltage (31.2V in for a 30.7V out) the DC bias effect is quite substantial for MLC caps in the 10uF range. I've been looking into the conductive polymer aluminum solid capacitor and started to wonder if I could substitute this for the MLC caps. The load is going to be a very constant load and will not have large or quick changes in current draw. Any words of wisdom or suggestions? Thanks!

-EM

[T3sl4co1l]

They don't give a stability diagram unfortunately, but the datasheet does insist:
- 1mA minimum load
- 10uF min Cout
- 100mohm max ESR

Anything that meets that spec will do.  You might need two 4.7uF 50V (1206 or 1210) X7R to get there, or one aluminum polymer.  Yes, polymer should definitely be suitable here.

Tim

[beaker353]

Thanks T3sl4co1l! I figured it would be compatible for my application, but didn't know if there was any "traps for young players" as Dave would say. Choosing the ideal type of cap for each application seems to be a bit of an art that isn't as straight forward as I wish it was. Further more, it's really not covered very much at all in my EET classes. I've serviced/modified/designed enough over the years to have learned some basic rules-of-thumb, but I still wish I knew more technical theory as to why...

The more I know, the more I know I don't know...

-EM