The LTC1562-2 is a low noise, low distortion continuous time filter with rail-to-rail inputs and outputs, optimized for a center frequency (fO) of 20kHz to 300kHz. Unlike most monolithic filters, no clock is needed. Four independent 2nd order filter blocks can be cascaded in any combination, such as one 8th order or two 4th order filters. Each block's response is programmed with three external resistors for center frequency, Q and gain, using simple design formulas. Each 2nd order block provides lowpass and bandpass outputs. Highpass response is available if an external capacitor replaces one of the resistors. Allpass, notch and elliptic responses can also be realized. The LTC1562-2 is designed for applications where dynamic range is important. For example, by cascading 2nd order sections in pairs, the user can configure the IC as a dual 4th order Butterworth lowpass filter with 90dB signal-to-noise ratio from a single 5V power supply. Low level signals can exploit the built-in gain capability of the LTC1562-2. Varying the gain of a section can achieve a dynamic range as high as 114dB with a 5V supply.