Patent ID: 6295012
Filing Date: 2001-09-25
Classification: H03M

Abstract:
A current cell circuit for use in digital-to-analog conversion, comprising:a regulated cascode current source;a differential current switch coupled to the regulated cascode current source, having first and second inputs for receiving complementary input signals, first and second outputs for presenting differential output signals, and a current source connection;wherein the regulated cascode current source comprises 1) a first cascode transistor having its source coupled to a DC reference source, 2) a second cascode transistor having its source coupled to the drain of the first cascode transistor, and its drain coupled to the current source connection of the differential current switch, 3) an impedance multiplier, wherein the impedance multiplier comprises a feedback transistor having its gate coupled to the drain of the first cascode transistor and the source of the second cascode transistor, its drain coupled to the gate of the second cascode transistor, and the source of the feedback transistor coupled to the DC reference source, and 4) a capacitance element having a first connection coupled to the DC reference source, and a second connection coupled to the gate of the second cascode transistor.