REF02: TEMP pin

Question

Hello, 
 I have a question about the TEMP pin of REF02. 
 The explanation of the TEMP pin has the description in page15 of the REF02 data sheet. 
 There is a description that recommends the OpAmp of a low bias like AD8641 to be used for here. 
 Is this bias current allowed up to how many pA? 
 Best Regards, 
 Mr.K

FormerMember · Accepted Answer

Mr. K, 
 We don't make cheap op amps. We make Lexus, not Civics. 
 Looking at the schematic, the temp pin comes from the heart of the bandgap reference, 
 so the more load on that pin, the more error. No, we do not characterize this. 
 The TEMP output is meant to be an uncalibrated relative indicator. There is part 
 to part variation. It simply tells you the part is hotter or colder than room. 
 If you want to measure temperature accurately, we have many good temp sensors, 
 such as ADT7320 or TMP05. 
 You can use any op amp you want, but the higher the bias current, the more the error on temp, 
 and the more you affect the reference output. 
 I would use two parts; one for an accurate reference voltage, and one for accurate temperature. 
 Harry

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