The LTC1164-8 is a monolithic ultraselective, 8th order, elliptic bandpass filter. The passband of the LTC1164-8 is tuned with an external clock and the clock-to-center frequency ratio is 100:1. The –3dB pass bandwidth is typically 1% of the filter center frequency. The stopband attenuation of the LTC1164-8 is greater than 50dB. The lower and upper stopband frequencies are less than 0.96 • center frequency and greater than 1.04 • center frequency, respectively. The LTC1164-8 requires an external op amp and two external resistors (see the circuit below). The filter’s gain at center frequency is set by the ratio RIN/RF. For a gain equal to one and an optimum dynamic range, RF should be set to 61.9k and RIN should be 340k. For gains other than one, RIN = 340k/Gain. Gains up to 1000 are obtainable. Setting the filter’s gain with input resistor RIN does not increase the filter’s wideband noise. The 270μVRMS wideband noise of the LTC1164-8 is independent of the filter’s center frequency. The LTC1164-8 is available in a 14-pin PDIP or a 16-pin surface mount SO Wide package. Applications * Asynchronous Narrowband Signal Detectors * Low Frequency Asynchronous Demodulators * Handheld Spectrum Analyzers * In-Band Tone Signaling Detectors * Ultraselectivity (50dB Attenuation at ±4% of Center Frequency) * Adjustable Passband Gain * Noise Independent of Gain * Filter Noise: 270μVRMS, VS = Single 5V Supply * Clock-Tunable (Center Frequency = fCLK/100) * Center Frequencies up to 5kHz, VS = ±5V (Typical ISUPPLY = 3.2mA) * Center Frequencies up to 4kHz, VS = Single 5V Supply (Typical ISUPPLY = 2.3mA)