What the dual temp-controlled resistor does for the BOM
The DS1856B-002 is a dual temperature-controlled resistor from Analog Devices, designed to compensate for temperature drift in optical modules or other precision analog circuits where a single resistive element shifts with ambient heat.
RoHS non-compliance — a sourcing flag
The Bulk package designation suggests it ships in tubes or trays rather than tape-and-reel, which is typical for through-hole or larger surface-mount devices that don't feed through a pick-and-place machine at high speed.
