**Appendix B. Body-to-Body (B2B) Mirror**

This section aims at explaining the body-to-body (B2B) interface which is exploited in each stage. Following the notation in Figure A1b, the current gain can be expressed as:

$$\frac{I\_{\rm out}}{I\_{\rm in}} = \frac{\mathcal{G}\_{\rm mb\_{\beta}}}{\mathcal{g}\_{\rm mb\_{A}}} \left( \frac{1}{1 + \frac{1}{\mathcal{\mathcal{G}}\_{\rm mb\_{A}} / \mathcal{\mathcal{G}}\_{\rm sb\_{A}}}} \right) \frac{1}{1 + s \frac{\mathcal{C}\_{\rm gd\_{A}} + \mathcal{C}\_{\rm bs\_{A}} + \mathcal{C}\_{\rm bs\_{B}} + \mathcal{C}\_{\rm bd} \chi\_{\beta}}{\mathcal{g}\_{\rm sb\_{A}} + \mathcal{g}\_{\rm mb\_{A}}}} \tag{A.3}$$

where also in this case *χβ* denotes the Miller approximation and can be derived as:

$$\chi\_{\mathcal{S}} = \frac{\mathcal{S}\_{mb\_{\mathcal{B}}}}{(\mathcal{g}\_{ds\_{\mathcal{B}}} + \mathcal{g}\_{load})} \tag{A4}$$

Finally, it can be concluded that the interface could be considered as a B2B mirror that enables a small-signal current mirror whose gain is fixed by properly sizing *MA* and *MB*.
