Adjustable shunt reference for precision bias and ADC rails
The Texas Instruments TL4051CQDBZR is a precision adjustable shunt voltage reference in a SOT-23-3 package. It delivers a ±0.5% initial tolerance and a 50 ppm/°C temperature coefficient across the full -40°C to 125°C operating range — enough accuracy to hold a 12-bit ADC reference or bias a sensor excitation rail without post-trim. Output is set with two external resistors from a minimum of 1.212 V up to 10 V, limited by the 12 mA maximum cathode current. The shunt topology means it behaves like a programmable Zener: the load and the reference share the same current path, so the bias resistor must be sized to keep at least 75 µA flowing into the cathode at all times — starve it below that and regulation drops out. Noise is specified at 20 µVrms over the 10 Hz to 10 kHz band, which is clean enough for most precision analog front-ends without an external filter cap. The -40°C to 125°C temperature grade qualifies it for industrial motor drives, automotive under-hood modules, and outdoor telecom equipment where the ambient swings hard.
What the ±0.5% tolerance and 50 ppm/°C drift mean for your BOM
The 20 µVrms noise figure is a typical value, not a tested maximum. In a low-impedance shunt configuration with a bypass at the cathode pin, that noise floor is usually adequate for 12-bit SAR ADC references.
Sourcing and lifecycle — active, no LTB risk
The TL4051CQDBZR carries an Active product status and a ROHS3 compliance rating. It is a current-production part that flows through both franchised distribution and the independent channel, so supply is stable for new designs and production replenishment alike. No premium for spot buys, no allocation risk — just a standard catalog reference that fills a BOM line without drama.