Features

• Steeper Roll-Off Than Bessel Filters
• High Speed: fC </= 200kHz
• Phase Equalized Filter in a 14-Pin Package
• Phase and Group Delay Response Fully Tested
• Transient Response Exhibits 5% Overshoot and No Ringing
• 65dB THD or Better Throughout a 100kHz Passband
• No External Components Needed
• Available in Plastic 14-Pin DIP and 16-Pin SO Wide Packages

Typical Application

Description

The LTC1264-7 is a 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 28dB attenuation (vs 12dB for Bessel), while at three times the cutoff frequency, the filter attains 55dB attenuation (vs 30dB for Bessel).

 The cutoff frequency of the LTC1264-7 is tuned via an external TTL or CMOS clock. The clock-to-cutoff frequency ratio of the LTC1264-7 can be set to 25:1 (pin 10 to V+) or 50:1 (pin 10 to V–). When the filter operates at clock-to-cutoff frequency ratio of 25:1, the input is double-sampled to lower the risk of aliasing.

The LTC1264-7 is optimized for speed. Depending on the operating conditions, cutoff frequencies between 200kHz and 250kHz can be obtained. (Please refer to the Passband vs Clock Frequency graphs.)

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