A voltage reference filter for a subscriber line interface circuit removes unwanted noise on a DC reference voltage sourced by a device, such as a codec, and employed by the subscriber line circuit as a differential mode voltage baseline. The DC reference voltage is coupled via a high pass filter to the sense amplifier. The filter blocks the DC component of the reference voltage and passes noise components to the sense amplifier. The reference port of an amplifier between the sense amplifier and a codec receives the same (noisy) reference voltage AC-coupled to the sense amplifier, and performs common mode rejection of noise components riding on the DC reference.