4.096V shunt reference with ±0.1% initial tolerance
The LM4040A41IDBZTG4 is a precision shunt voltage reference from Texas Instruments, delivering a fixed 4.096V output with a tight ±0.1% initial tolerance.
Shunt topology — resistor selection drives the BOM
Because this is a shunt reference, an external series resistor from the supply to the cathode pin sets the operating current. The cathode current is 88 µA typical, and the device can sink up to 15 mA at the output. The resistor value must supply enough current to keep the reference in regulation at minimum supply voltage while staying below the 15 mA ceiling at maximum supply and zero load. A 1% resistor with adequate power rating is the standard choice; the BOM cost engineer should budget for that resistor as part of the reference cost.
Package and marking verification
The device comes in a SOT-23-3 package (also listed as TO-236-3 or SC-59), supplied on Tape & Reel. The laser etch on the package top should read the TI date-code format consistent with the plant and week — any mismatch in font or layout is a red flag for re-marked stock. Surface-mount reflow profile follows standard SOT-23 guidelines; no special moisture sensitivity level is noted, but a pre-bake at 125°C for 24 hours is prudent if the reel seal is broken.
No second-source or direct replacement is listed in the TI portfolio; the LM4040 family includes multiple voltage options and tolerance grades, but this exact 4.096V ±0.1% variant has no pin-compatible alternate on the official cross-reference.