| 摘要 |
A programmable capacitor array including a plurality of user-selectable, numerically weighted capacitors, each of which includes at least one fixed capacitor and one manufacturer-controlled trim capacitor, advantageously provides a variety of selectable capacitance values for a programmable analog integrated circuit. When coupled to a memory, for example a static memory, switches can be controlled that determine whether a particular fixed capacitor (user-selectable) or trim capacitor (manufacturer-selectable) is electrically coupled into the circuit. User access to those portions of memory controlling switches associated with the trim capacitors can be restricted via an I/O interface and security command. Such programmable capacitor arrays allow efficient implementation of user-programmable filter circuits where the user can conveniently program or reprogram a variety of filter parameters.
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