2.5 V shunt reference with ±1.5% tolerance
The LM385BMX-2.5/NOPB: This is a fixed 2.5 V shunt voltage reference in an 8-SOIC surface-mount package. The ±1.5% tolerance means the output voltage sits between 2.4625 V and 2.5375 V at 25°C — tight enough for most 8-bit ADC references or comparator threshold networks, but not precision enough for a 12-bit+ ADC without calibration. The shunt architecture requires an external series resistor to set the bias current; the device sinks 20 µA minimum cathode current and can handle up to 20 mA continuous output. That 20 mA ceiling is the total current through the reference plus any load — budget the load current so the sum stays under 20 mA across the full temperature range.
Not rated for automotive under-hood, industrial motor drives, or outdoor telecom cabinets where ambient temperatures exceed 70°C.
Noise floor for sensitive analog rails
Wideband noise from 10 Hz to 10 kHz is specified at 120 µVrms. For a 2.5 V reference feeding a 10-bit ADC with a 2.5 V full-scale range (1 LSB ≈ 2.44 mV), this noise level is acceptable. For a 16-bit ADC (1 LSB ≈ 38 µV), the noise would dominate the least-significant bits and a lower-noise reference should be considered.