For applications requiring a negative and
positive reference voltage, the REF70 and OPA211 can be used to provide a dual-supply
reference from a 5-V supply.
Figure 9-2 shows the REF70 used to provide a 2.5-V supply reference voltage and -2.5V negative
reference voltage. The low noise performance of the REF70 complements the low noise of
the OPA211 to provide an accurate solution for split-supply applications. Take care to
match the temperature coefficients of R1 and R2.