I'm looking for ldo's (3.3 and 10V) without esr requirements on the output caps.
Unfortunately I ordered some samples from onsemi and they do have requirements of <0.4ohm. After looking in my closet I found a reel of tantal caps of 68uF/10V with an esr of 0.24Ohm. But I'm not sure if these orange tantals (Vishay 595D686x0010c , case CWR10 style) are rated for automotive purposes.
Which ldo's could I use for automotive purposes without esr requirements?
Nick
It sounds like you only have samples so far and for testing those the Tantalums you have sound fine. The esr you say they have is lower than required so you are OK there and the operating voltage is OK for prototype work and for the 3.3 output in production. I would use a higher breakdown voltage for production with the 10 volt output. You can find lots of LDO regulators out there and would have to look at the data sheets to see what they spec for the output caps. You are always going to be better off with lower ESR parts but they do cost a little more. With only one cap required the extra cost should not be a big deal.
EDIT: BTW I would look for low ESR Ceramics myself instead of tantalums to design in as they are cheaper and do not explode if installed in reverse.
Thanks for you reply,
The 10V ldo is indeed problematic. I have not yet found a proper cap for that one. Do you have idea's about other companies hwo sell automotive ldo's that do not have these esr requirements?
I guess we need the load requirements. Presume you have auto type input range into the part.
EDIT: Also here is an ap note explaining about the ESR needs of LDOs in general..
Reading both the TI Ap note and National Semi's data sheet for the LM9076 you find that a simple fix is to add a one ohm series resistor in the output caps ground connection. This makes sure you have a minimum ESR.
