Exponential ROM table tuning using trim for frequency agile analog filters

摘要

A tunable and trimmable analog filter may include a tunable analog filter and a trimming circuit. The tunable analog filter may set the frequency of a characteristic of the tunable analog filter based on a digital tuning signal that is indicative of a desired frequency of the characteristic. However, the tunable analog filter may contain components having values that deviate from specified values due to var during manufacture of the tunable analog filter. The value deviations can cause the frequency of the characteristic not to precisely match the frequency indicated by the digital tuning signal. The trimming circuit may include a non-volatile memory that contains data. The trimming circuit may receive tuning information indicative of a desired frequency for the characteristic of the tunable analog filter. The trimming circuit may generate the digital tuning signal by trimming the tuning information to compensate for the deviations in component value and by using the data contained within the non-volatile digital memory.