Adjustable shunt reference with tight tolerance
The TL431BCDBVT is a three-terminal adjustable shunt regulator from Texas Instruments' TL431 family, delivering a 2.495 V reference that can be set to any value between that minimum and 36 V using two external resistors. Its ±0.5% initial tolerance suits precision bias and feedback circuits where a standard 1% or 2% part would shift the output beyond the design window.
Output current and cathode current limits
Minimum cathode current for regulation is 600 µA — below that threshold the reference output may drift, so the external resistor from cathode to the supply rail must be sized to keep at least 600 µA flowing through the device at all load conditions.