Other Parts Discussed in Thread: LM4132, REF1933, REF3433, REF3033, REF3133, REF2033, TLE2062
I'm frustated and annoyed: My LM4132-Q1-3.3V reference produces up to 4.0V at the output when being powered by a 5V supply (mains transformer, rectifier, storage cap, LM7805). It's no problem when the 5V rises fast. But it IS a problem when the power up lasts up to 10msec and the typical 100Hz rectifier charging rises can be seen at output of LM7805 before the output voltage stabilizes to 5V. Then the output voltage of LM4132 seems to be glued to the input voltage and rises and rises and rises... Sometimes even 4.0V is reached and the output voltage shows a flat plateu as if the output is internally zener clamped to 4,0V.
This behaviour can be seen with all sorts of decoupling at input and output and with all sorts of loads. It has only do to with the timing of the rise of input voltage.
I'm annoyed because I cannot read anything about this strange performance in the datasheet. Or shall I read between the lines? Shall I expect a strange behaviour only because no power up diagram is shown in the datasheet??
My problem is, that I must power circuitry at the output of LM4132 which can only withstand 4.0V (absolute maximum rating). So, how to proceed? Is there any limit of output voltage of LM4132? Or must I expect even higher voltages than 4.0V? Or can I count on a hidden internal zener clamping to 4.0V?
Or is it better to switch to another reference like the REF1933? Does this reference show a limit of output voltage that I can trust? Or is there a new set of non documented surprises waiting for me??