Inventors:
Mikael Gustavsson - Eatontown NJ
Nianxiong Tan - Newport Beach CA
Assignee:
Globespanvirata, Inc. - Red Bank NJ
International Classification:
H03M 300
US Classification:
341143, 341118, 341120, 341144
Abstract:
A SINC filter for an oversampling Sigma-Delta digital to analog converter (OSDAC) having a cascaded construction that results in reduced sensitivity to capacitor mismatch. Specifically, the SINC filter circuit filter may be defined by a transfer function H(z), which is further defined by first constituent transfer functions H (z) and H (z). The constituent transfer functions may be implemented in a cascaded fashion. Preferably, one of the cascaded sections includes a resistor string that defines a plurality of reference voltages. A plurality of switching elements are configured to controllably switch these reference voltages to a capacitor of a tap.