Applications with only a positive supply voltage often require an additional stable voltage in the middle of the analog-to-digital converter (ADC) input range to bias input bipolar signals. The REF19xx provides a reference voltage (VREF) for the ADC and a second highly-accurate voltage (VBIAS) that can be used to bias the input bipolar signals.
The REF19xx offers excellent temperature drift (25 ppm/°C, max) and initial accuracy (0.1%) on both the VREF and VBIAS outputs while operating at a quiescent current less than 430 µA. In addition, the VREF and VBIAS outputs track each other with a precision of 6 ppm/°C (max) across the temperature range of –40°C to 85°C. All these features increase the precision of the signal chain and decrease board space, while reducing the cost of the system as compared to a discrete solution. Extremely low dropout voltage of only 10 mV allows operation from very low input voltages, which can be very useful in battery-operated systems.
Both the VREF and VBIAS voltages have the same excellent specifications and can sink and source current equally well. Very good long-term stability and low noise levels make these devices ideally-suited for high-precision industrial applications.
