Patent ID: 7005911

Claim:
A multiplexer adapted to provide a selected one of a first voltage level or a second voltage level on a multiplexer output terminal, wherein the first voltage level is of a first magnitude with respect to a reference and the second voltage level is of a second magnitude with respect to the reference, and wherein the first magnitude is greater than the second magnitude, the multiplexer comprising: a first voltage switch having: a first voltage-switch input terminal receiving the first voltage level; and a first voltage-switch output terminal connected to the multiplexer output terminal, wherein the first voltage switch is selectively activated to provide the first voltage level to the multiplexer output terminal; a second voltage switch selectively activated to provide the second voltage level to the multiplexer output terminal, the second voltage switch including: a first transistor having: a first current-handling terminal receiving the second voltage level; a second current-handling terminal connected to the multiplexer output terminal; a first control terminal; and a well terminal; a second transistor having a third current-handling terminal, a second control terminal, and a fourth current-handling terminal connected to the well terminal of the first transistor; an enable circuit having an enable circuit terminal connected to the first control terminal to selectively activate the second voltage switch; a well-voltage select circuit having a voltage-select terminal connected to the second control terminal; a first well-reference terminal connected to the third current-handling terminal; a third transistor having a fifth current-handling terminal connected to the well terminal, a third control terminal, and a sixth current-handling terminal; and a second well-reference terminal connected to the sixth current-handling terminal; wherein the first well-reference terminal connects to the first voltage level in response to deactivating the second voltage switch and the second well-reference terminal connects to the second voltage level in response to deactivating the first voltage switch; wherein the well-voltage select circuit comprises a level shifter having a level shifter output terminal connected to the second control terminal.