1. REFERENCE CIRCUITS A Reference Circuit is an independent voltage or current source which has a high degree of precision and stability. • Requirements of a Reference Circuit • Output voltage/current should be independent of Power Supply • Output voltage/current should be independent of temperature • Output voltage/current should be independent of process variations.

3. SENSITIVITY Sensitivity is a measure of dependence of Vref (Iref) upon a parameter or variable x which influences Vref (Iref). ; Where x could be VDD or temperature

4. TEMPERATURE DEPENDANCE Minimize the fractional Temperature Coefficient

5. BOOTSTRAPPED CURRENT SOURCE

11. VBE REFERENCE CURRENT SOURCE

13. Simple Voltage References Objective is to minimize • Types of Voltage References: • Voltage Dividers – Active • MOS Diode Reference • PN Junction Diode Reference • Gate-Source Threshold Voltage Reference • Base-Emitter Reference Circuit

14. ACTIVE VOLTAGE DIVIDERS

15. PN JUNCTION VOLTAGE REFERENCE

16. VBE MULTIPLIER

17. PN JUNCTION

19. GATE SOURCE REFERENCE CIRCUIT

20. GATE SOURCE VOLTAGE FOR CONSTANT CURRENT (STRONG INVERSION)

21. GATE SOURCE REFERENCE CIRCUIT

23. BANDGAP VOLTAGE REFERENCE

27. By taking the derivative at T0 (assuming that JC has a temperature dependence of Tα , the dependence of VBE withtemperature is given by

31. CURVATURE CORRECTION ?

32. CORRECTION TOPOLOGY