Analog Devices Inc. LTC1064-4CSW

LTC1064-4CSW Lowpass Filter Product Summary

The LTC1064-4CSW from Analog Devices Inc. is a versatile, high-performance switched capacitor filter. Engineered for demanding signal processing environments, it offers an 8th order programmable Cauer lowpass response, operating at cutoff frequencies up to 100 kHz. Housed in a 16-lead SOIC package, the LTC1064-4CSW is especially suited for advanced anti-aliasing, telecom, and sinewave generation applications that demand precise filtering and low noise operation.

Principal Electrical and Functional Features of the LTC1064-4CSW

At the core of the LTC1064-4CSW is its robust ability to deliver up to 80 dB stopband attenuation and extremely low total wideband noise of 135 μV RMS. The chip allows for two distinct operating modes:

Cauer response (Pin 10 at V⁺): Delivers a 50:1 clock-to-cutoff ratio with ±0.1 dB passband ripple and up to 100 kHz cutoff, ideal for applications where sharp roll-off and minimal ripple are required.

Transitional Butterworth-Cauer response (Pin 10 at V⁻): Achieves a 100:1 clock-to-−3 dB ratio, offering lower noise and delay nonlinearity with stopband attenuation of 92 dB at 2.5× the −3 dB frequency, and cutoff frequencies up to 50 kHz.

The LTC1064-4CSW is compatible with both TTL and CMOS clock inputs and operates from single or dual supplies up to ±8V. Additionally, its design supports input frequency ranges up to 50 times the filter cutoff frequency, reflecting its suitability for high-speed signal processing tasks.

LTC1064-4CSW Performance Evaluation in Practical Engineering Applications

In signal conditioning architectures, the LTC1064-4CSW offers competitive overall performance compared to multi-op amp active filters, especially regarding harmonic distortion (≤0.03% THD) and noise. Test setups often utilize square wave inputs and buffer op amps to validate transient response and output integrity. For frequencies above 20 kHz, careful compensation is required to maintain optimal passband ripple—achievable through strategic external component selection as demonstrated in application notes and performance tables.

Engineers designing telecommunication filters or anti-aliasing stages for data acquisition systems can leverage the LTC1064-4CSW’s clock sweep capability to dynamically tune cutoff points. Typical transient and frequency response figures affirm the device’s ability to maintain amplitude and phase performance across a wide temperature and voltage range, ensuring stability in production environments.

LTC1064-4CSW Pin Layout and Design Recommendations for Specific Uses

Optimized utilization of the LTC1064-4CSW’s pin configuration is central to unlocking its full performance envelope. Key guidance includes:

Compensation pins (INV C, COMP1, INV A, COMP2): These require precise external capacitors to ensure minimum ripple at higher cutoff frequencies.

Input/output pins: Input (Pin 2) is typically connected to a 12k resistor to the op amp’s inverting input and features static protection. Output (Pin 9) should ideally be buffered and filtered to mask clock feedthrough, especially in high-precision scenarios.

AGND and supply pins: For low noise operation, dual supply configs should ground AGND pins to a solid plane, and supplies should be bypassed with 0.1 μF capacitors; Schottky diodes (e.g., 1N5817) are recommended to shield against high turn-on transients.

Pin 10 logic: Tying Pin 10 to V⁺ enables the classic Cauer response, while V⁻ engages the transitional response. For unique filtering profiles, connecting to ground yields a hybrid response.

Short, shielded connections between critical pins (e.g., Pins 7 and 14) are advised to minimize noise and signal degradation, with recommended PCB layouts to support stability. Unused pins, such as Pin 8 (NC), should be grounded.

Available LTC1064-4CSW Packaging Types

The LTC1064-4CSW is delivered in a standard 16-lead plastic small outline (SOIC) wide-body package. This offers surface-mount convenience for automated assembly and robust performance in vibration-prone environments, while an alternative 14-pin PDIP package (LTC1064-4) is available for through-hole applications. Engineers must consider mechanical dimensions, pin spacing, and thermal management in final product integration to assure reliability and ease of servicing.

Alternative or Substitute Models Comparable to the LTC1064-4CSW

For designs requiring flexibility or multi-source support, it is notable that the LTC1064-4CSW is part of a compatible product family. Pin compatibility is maintained with the LTC1064-1, LTC1064-2, and LTC1064-3 models, enabling straightforward substitutions or upgrades. These alternatives exhibit similar switched capacitor filter architectures but may differ in frequency response, compensation requirements, or maximum cutoff capabilities. Careful review of the specific performance benchmarks and application domain requirements is recommended when selecting an equivalent or replacement part.

Conclusion

: LTC1064-4CSW as a Strategic Choice for Precision Filtering Applications

The LTC1064-4CSW stands out as a pivotal component for precision filtering in modern electronic systems. Its blend of configurable frequency response, low noise, and high stopband attenuation makes it an excellent candidate for telecom, anti-aliasing, and signal generation tasks. Understanding the nuances of its operation—including pin configuration, compensation, and package selection—enables engineers and procurement professionals to leverage its strengths and secure robust, scalable designs for advanced filtering requirements. When evaluating filtering solutions for new products or upgrades, the LTC1064-4CSW merits serious consideration as a top choice for high-performance applications.