That means Microchip has flagged it for eventual discontinuation; it is not the part to drop into a fresh BOM. Existing production lines that already qualify this reference can still source it through independent distribution, but the window for last-time-buy planning is open now.
10 V fixed output, ±1 % — the tolerance that matters
This is a fixed 10 V shunt reference, not an adjustable type. The 150 ppm/°C temperature coefficient means the output drifts about 1.5 mV over a 100°C swing — fine for 8- to 10-bit systems, marginal for 12-bit designs without calibration.
15 mA output, 110 µA cathode — biasing the shunt
The shunt reference needs a bias resistor from the supply to the cathode to set the operating current. The 15 mA maximum output current is the load it can sink while maintaining regulation; the 110 µA minimum cathode current is the floor below which the reference drops out of regulation. A typical design biases it at 1 mA to cover both the load and the cathode minimum with margin.
SOT-23-3 — footprint and fit
Three-pin SOT-23-3 (also listed as TO-236-3 / SC-59). Surface-mount only. The pinout is standard for the LM4040 family: cathode, anode, and no-connect.