Current Sources and Voltage References

476

Applying adjustable-series bandgaps

voltage (V

OUT

) and drift (∆V

OUT

) over the temperature range. This would mean that a

design that started out with a 0.1% initial accuracy, a 10 ppm/°C tempco, and a long-

term stability of 100 ppm/°C could be significantly improved. The resulting reference,

using digital compensation, would be close to having a 0.01% initial accuracy, a 1

ppm/°C tempco, and a long-term stability of less than 10 ppm/°C. In other words, an

order-of-magnitude improvement could be made, or maybe more. A higher than

desired noise level could be reduced with a separate (buffered) analog low-pass filter.

To do all this, one would need to ...