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Data sheet help - TI REF5025 decoupling

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Full Member level 2
Dec 17, 2011
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The first image is taken from the data sheet for a TI 8x DAC evaluation board. it shows C11 at the REF5025 output with a 1R5 Resistor to GND.

When I checked the data sheet for the REF5025 it doesn't show this R to GND (second image) - it quotes "A 1-μF to 50-μF, low-ESR output capacitor (CL) must be connected from VOUT to GND. The ESR value should be less than or equal to 1.5 Ω."

So - these two sheets seem to contradict each other. The original data sheet says a Cap with an ESR ≤1R5 and the DAC eval data sheet shows a Cap with an R of 1R5.

Any comments on what one might be right or wrong?


Whichever one works for you is right. If this is a bipolar shunt
reference then you must beware transient saturation in the
output device which can set up a relaxation oscillation (not
small signal and missed by any analysis which does not induce
said saturation). A too-large cap or one with too-low ESR
can do this on supply or load steps.

Check high temperature as a worst case condition. Try a
matrix of capacitor values, ESR (by part number) and
series resistor (which can also help HF stability if a zero
around 15MHz is what you need) and pick a combo that
puts you well away from all of the various forms of

Datasheets and app notes are the beginning of wisdom,
not the end.

Maybe they put in the resistor just in case, if not needed just jumper it with a 0ohm resistor.
Then you would have a larger number of possible capacitors that could be made to work.

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