Low Power 8th Order Pin Selectable Butterworth or Bessel Lowpass Filter

The LTC1164-5 is a monolithic 8th order filter; it approximates either a Butterworth or a Bessel lowpass response. The LTC1164-5 features clock-tunable cutoff frequency and low power consumption (4.5mA with ±5V supplies and 2.5mA with single 5V supply).

Low power operation is achieved without compromising noise or distortion performance. With ±5V supplies and 10kHz cutoff frequency, the operating signal-to-noise ratio is 86dB and the THD throughout the passband is 0.015%. Under the same conditions, a 77dB signal-to-noise ratio and distortion is obtained with a single 5V supply while the clock feed through is kept below the noise level. The maximum signal-to-noise ratio is 92dB.

The LTC1164-5 approximates an 8th order Butterworth response with a clock-to-cutoff frequency ratio of 100:1 (Pin 10 to V–) or 50:1 double-sampled (Pin 10 to V+ and Pin 1 shorted to Pin 13). Double-sampling allows the input signal frequency to reach the clock frequency before any aliasing occurrence. An 8th order Bessel response can also be approximated with a clock-to-cutoff frequency ratio of 140:1 (Pin 10 to ground). With ±7.5V supply, ±5V supply and single 5V supply, the maximum clock frequency of the LTC1164-5 is 1.5MHz, 1MHz and 1MHz respectively. The LTC1164-5 is pin-compatible with the LTC1064-2 and LTC-1064-3.

Applications

* Anti-Aliasing Filters

* Battery-Operated Instruments

* Telecommunications Filters

* Smoothing Filters

* Pin Selectable Butterworth or Bessel Response

* 4mA Supply Current with ±5V Supplies

* fCUTOFF up to 20kHz

* 100µVRMS Wideband Noise

* THD < 0.02% (50:1, VS = ±7.5V, VIN = 2VRMS)

* Operates with a Single 5V Supply (1VRMS Input Range)

* 60µVRMS Clock Feedthrough (Single 5V Supply)

* Operates up to ±8V Supplies

* TTL/CMOS-Compatible Clock Input

* No External Components

* Available in 14-Pin DIP and 16-Pin SO Wide Packages