Features

• Ultraselectivity
  (50dB Attenuation at ±4% of Center Frequency)
• Adjustable Passband Gain
• Noise Independent of Gain
• Filter Noise: 270μV_RMS, V_S = Single 5V Supply
• Clock-Tunable (Center Frequency = f_CLK/100)
• Center Frequencies up to 5kHz, V_S = ±5V
  (Typical I_SUPPLY = 3.2mA)
• Center Frequencies up to 4kHz, V_S = Single 5V Supply
  (Typical I_SUPPLY = 2.3mA)

Typical Application

Description

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 R_IN/R_F. For a gain equal to one and an optimum dynamic range, R_F should be set to 61.9k and R_IN should be 340k. For gains other than one, R_IN = 340k/Gain. Gains up to 1000 are obtainable. Setting the filter’s gain with input resistor R_IN does not increase the filter’s wideband noise. The 270μV_RMS 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.