Trimming Impedance Between Two Nodes Connected To A Non-Fixed Voltage Level

摘要

A T-network containing three impedance is provided between two terminating ends not connected to ground. Two impedances may be connected in series between the two terminating ends. A third impedance may be connected between the junction of the first two impedances and a fixed voltage (e.g., ground). Switches may be used to trim the third voltage, thus obtaining a desired voltage between the two terminating ends. A terminal of any switches used for trimming can be connected to the fixed voltage node, thereby ensuring that the impedance introduced by the switches does not change substantially during different operating situations.