Patent ID: 8619382

Claim:
An apparatus, comprising: a first differential pair of PNP BJTs having a first PNP BJT and a second PNP BJT; a first tail current source coupled into the emitter of the PNP BJTs of the first differential pair; a second differential pair of NPN BJTs having a first NPN BJT and a second NPN BJT; a second tail current source coupled into the emitters of the NPN BJTs of the second differential pair; wherein a collector of each of the PNP BJTs of the first differential pair are coupled to a corresponding collector the NPN BJTs of the second differential pair; a first shift up PNP BJT having an emitter coupled to the collector of a first PNP BJT of the first differential pair, a second shift up PNP BJT having an emitter coupled to the collector of the second PNP BJT of the first differential pair; a first shift down NPN BJT having an emitter coupled to the collector of the first PNP BJT of the second differential pair; a second shift up BJT having an emitter coupled to the collector of a second PNP BJT of the second differential pair; and a first and second amplifier coupled to the emitters of the a first shift up PNP BJT and the second shift up PNP BJT.