Patent ID: 6084461
Filing Date: 2000-07-04
Classification: H03F

Abstract:
An apparatus including a charge sensitive amplifier with high common mode signal rejection, said charge sensitive amplifier comprising:a current controlled transistor circuit configured to receive a dc input reference with a common mode input signal and in accordance therewith provide a first common mode signal component, wherein a ratio of said first common mode signal component to said common mode input signal equals a first signal gain;a voltage controlled transistor circuit, coupled to said current controlled transistor circuit, configured to receive a data input signal with said common mode input signal and in accordance therewith provide a data signal component and a second common mode signal component, wherein a ratio of said second common mode signal component to said common mode input signal equals a second signal gain; andan output circuit, coupled to one or both of said current and voltage controlled transistor circuits, configured to receive and combine said data signal component and said first and second common mode signal components and in accordance therewith provide an output signal which corresponds to said data input signal, wherein a ratio of said output signal to said data input signal substantially equals said second signal gain;wherein said data input signal is single-ended and said dc input reference and said data input signal are unrelated to one another;wherein said first and second signal gains are substantially equal and of opposite polarities and said first and second common mode signal components substantially cancel one another; andwherein said current and voltage controlled transistor circuits are coupled together in a totem pole circuit configuration.