Up-right part of Fig. 1 shows the reference current generator. It
incorporates a PMOS curr ent mirror and a voltage regulator.
The regulator drives an active load formed by a diode
connected PMOS transistor with the same size of MPD5. The
regulator must be carefully designed to maintain stability. The
PMOS transistor MpM2 has the same dimension as MpM1. MNMI
and MNM2 constitute a current mirror with a gain of M. Thereby
the Iref is presented as