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CDC3RL02: ESR Range for LDO

Part Number: CDC3RL02

For the CDC3RL02, I have see two posts stating that the LDO capacitor must have a minimum ESR of 100-mOhms and a maximum of 1000-mOhms.  Only the minimum is stated in the spec.  There is no reference design for the CDC3RL02 to show what actual BOM part was used for the LDO capacitor.  

In my experience, a ceramic capacitor will be lower than 100-mOhms and a tantalum (smaller body) will be larger than 1000-mOhms.  Therefore, other than adding a discrete resistor, I am not sure what native capacitor would be recommended for a design.  We don't want a capacitor that is larger than the part we are using it on.

In one post, the LMH2191TM reference design was listed as a "substitute" reference design for the CDC3RL02.  Looking at the LMH2191TM, it looks to possibly be a National Semicoductor version of the TI CDC3RL02 version.  The LMH2191TM only needs 5-mOhm to 500-mOhm ESR, which is in the range of most MLCCs.

Are the LMH2191TM and the CDC3RL02 equivalent sister parts, such that the LMH2191TM can be used instead to use regular parts.

For the CDC3RL02, is 1000-mOhms really the maximum?  We have a tanatlum polymer parts that is 0402, 2.2uF, 6.3V and 1500-mOhms.

Is there a recommended capacitor for the CDC3RL02 that meets the requirements?

We would rather not redo our PCBs to add the resistor to control the ESR.


  • Hi Matt,

    Yes the requirement for ESR is 100 to 1000 milliohm for CDC3RL02 as suggested in previous E2E post

    LMH2191TM  have similar function to the CDC3RL02 so we can use that. 

    For capacitor recommendation, I have to look if there is any verification board schematic that I can look and  find you a part number. 



  • Hi Matt,

    Unfortunately, I wasn't able to find any board for reference on this part. I think to we have use the series resistor route to control this or use the  LMH2191TM  which has similar function and land pattern. There are some changes in package size but that should not cause any problem since package can be mounted on same land pattern as CDC3RL02.