Precision 5 V anchor for the BOM
The REF35500QDBVR: That tolerance band is tight enough to set the ADC reference without a trim pot in most 12- and 14-bit systems — the error budget stays inside the converter's INL floor. Temperature drift is spec'd at 12 ppm/°C. For a 5 V output, that's about 16.5 µV p-p of flicker noise and 3.5 µV RMS of broadband — low enough that the reference is not the dominant noise source behind a 16-bit SAR ADC with a 100 kSPS throughput.
Input headroom and quiescent current — battery-system fit
Input voltage range is 5.25 V to 6 V. That 250 mV dropout minimum means the reference needs a clean 5.25 V rail — a 5 V LDO output will not cut it unless boosted above the nominal. A 5.5 V or 6 V rail from a boost converter or a separate 6 V bias supply is the practical feed. Quiescent current is 900 nA typical. In a battery-powered sensor node that sleeps between readings, the reference's own draw is negligible compared to the MCU's deep-sleep current. The reference stays powered and settled, so the first conversion after wake-up is valid without a warm-up delay. Output current is limited to 10 mA. That is enough to bias the ADC reference input and a small resistive divider, but not to drive an external buffer or a heavy load. If the downstream circuit draws more than 10 mA from the reference pin, the output accuracy degrades — plan a separate buffer op-amp for loads above that ceiling.
SOT-23-6 — board integration note
The part comes in a 6-lead SOT-23 package (SOT-23-6) with a 0.95 mm pitch and a 2.9 mm body width. No exposed pad — thermal dissipation goes through the leads and the copper traces. A 10°C/W improvement in RθJA is achievable with a 25 mm² copper island on the top layer under the package, but the datasheet's junction-to-ambient figure assumes minimal copper. For the 10 mA max load and 900 nA quiescent, self-heating is negligible — the junction stays within a degree of ambient even at 125°C. Tape and Reel or Cut Tape packaging — the reel quantity is the standard 7-inch reel for SOT-23.
Active lifecycle — no end-of-life signal
The ±0.05% tolerance grade and the 12 ppm/°C drift place this reference in the precision band of TI's REF35xx family. No official second-source exists on this exact order code, but the LM4132AMF-4.1/NOPB is a close parametric peer: same ±0.05% tolerance, 20 ppm/°C drift, and a 4.096 V output in a SOT-23-5 package. The REF35500's 5 V output is the main difference — the LM4132's 4.096 V is a common ADC reference for 12-bit converters with a 4.096 V full-scale range. If the BOM calls for a 5 V reference, the REF35500 is the direct fit; the LM4132 is a drop-in only if the ADC reference input accepts 4.096 V.