Current Sources and Voltage References

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Bandgap voltage references

Now we can calculate the bandgap voltage using equation 14.7:

We can now determine the reference’s output voltage using equation 14.9, where R

5

and R

6

, together with the bandgap voltage, set the amplifier’s gain:

As a result, this venerable bandgap reference IC can produce a stable output of 2.5

volts at 5 mA, with an initial accuracy of ±10 mV (equals ±0.4%) maximum and a qui-

escent current of 1.5 mA maximum. It will probably have a low-frequency noise volt-

age of less than 10 µV peak-to-peak (pk-pk), along with a tempco of less than 25 ppm/

°C, over a 0°C to +70°C temperature span. The device will be suitable (with tr ...