LTC1569-7

LTC1569-7 Linear Phase, DC Accurate, Tunable, 10th Order Lowpass Filter FEATURES s s s s s s s s s s s U APPLICATIO S s s One External R Sets Cutoff Frequency Root Raised Cosine Response Up to 300kHz Cutoff on a Single 5V Supply Up to 150kHz Cutoff on a Single 3V Supply 10th Order, Linear Phase Filter in an SO-8 DC Accurate, VOS(MAX) = 5mV Low Power Modes Differential or Single-Ended Inputs 80dB CMRR (DC) 80dB Signal-to-Noise Ratio, VS = 5V Operates from 3V to ±5V Supplies Furthermore, its root raised cosine response offers the optimum pulse shaping for PAM data communications. The filter attenuation is 50dB at 1.5 fCUTOFF, 60dB at 2 fCUTOFF, and in excess of 80dB at 6 fCUTOFF. DC-accuracysensitive applications benefit from the 5mV maximum DC offset. The LTC1569-7 is the first sampled data filter which does not require an external clock yet its cutoff frequency can be set with a single external resistor with a typical accuracy of 3.5% or better. The external resistor programs an internal oscillator whose frequency is divided by either 1, 4 or 16 prior to being applied to the filter network. Pin 5 determines the divider setting. Thus, up to three cutoff frequencies can be obtained for each external resistor value. Using various resistor values and divider settings, the cutoff frequency can be programmed over a range of seven octaves. Alternatively, the cutoff frequency can be set with an external clock and the clock-to-cutoff frequency ratio is 32:1. The ratio of the...