Low Power, Linear Phase 8th Order Lowpass Filter

The LTC1164-7 is a low power, clock-tunable monolithic 8th order lowpass filter with linear passband phase and flat group delay. The amplitude response approximates a maximally flat passband and exhibits steeper roll-off than an equivalent 8th order Bessel filter. For instance, at twice the cutoff frequency the filter attains 34dB attenuation (vs12dB for Bessel), while at three times the cutoff frequency the filter attains 68dB attenuation (vs 30dB for Bessel). The cutoff frequency of the LTC1164-7 is tuned via an external TTL or CMOS clock.

Low power is achieved without sacrificing dynamic range. With single 5V supply, the S/N + THD is up to 75dB. Optimum 91dB S/N is obtained with ±7.5V supplies.

The clock-to-cutoff frequency ratio of the LTC1164-7 can be set to 50:1 (pin 10 to V+) or 100:1 (pin 10 to V–).

When the filter operates at the clock-to-cutoff frequency ratio of 50:1, the input is double-sampled to lower the risk of aliasing.

The LTC1164-7 is pin-compatible with the LTC1064-X series and LTC1264-7.

Applications

* Data Communication Filters

* Time Delay Networks

* Phase Matched Filters

* Better Than Bessel Roll-Off

* fCUTOFF up to 20kHz, Single 5V Supply

* ISUPPLY = 2.5mA (Typ), Single 5V Supply

* 75dB THD + Noise with Single 5V Supply

* Phase and Group Delay Response Fully Tested

* Transient Response with No Ringing

* Wide Dynamic Range

* No External Components Needed

* Available in 14-Lead N and 16-Lead SW Packages