Pin-Programmable Universal and Bandpass Filters

The MAX263/264 and MAX267/268 CMOS switched-capacitor active filters are designed for precision filtering applications. Center frequency, Q, and operating mode are all selected via pin-strapped inputs. The MAX263/264 uses no external components for a variety of bandpass, lowpass, highpass, notch and allpass filters. The MAX267/268 is dedicated to bandpass applications and includes an uncommitted op-amp. Two second-order filter sections are included in both devices.

An input clock and a 5-bit programming input precisely set the filter center/corner frequency. Q is also programmed from 0.5 to 64. Separate clock inputs for each filter half operate either an external clock or a crystal.

The MAX263 and 267 operate with center frequencies up to 57kHz while the MAX264 and 268 extend the f0 range to 140kHz by employing lower fCLK/f0 ratios. The MAX263/264 is supplied in 28 pin wide DIP and small outline packages while the MAX267/268 is supplied in 24 pin narrow DIP and wide SO packages. All devices are available in commercial, extended, and military temperature ranges.

* 32-Step Center Frequency Control

* 128-Step Q Control

* Independent Q and f0 Programming

* Guaranteed Clock to f0 Ratio—1% (A grade)

* 75kHz f0 Range (MAX264/268)

* Single +5V and ±5V Operation