LTC1068-50CG#TRPBF

Overview

The LTC1068-50CG#TRPBF is a clock-tunable, quad second-order switched-capacitor filter building block housed in a 28-lead SSOP package. It features four matched low-noise sections with a nominal clock-to-center frequency ratio of 50:1. The device supports operating supply voltages ranging from 3.14V to ±5.5V and draws a typical power supply current of 4.5mA at a single 5V supply. Electrical characteristics include a DC open-loop gain of 85dB, a gain-bandwidth product of 4MHz, and a slew rate of 7V/µs. The center frequency error is typically ±0.3% with a maximum of ±0.8%. Clock feedthrough is specified at 0.16mVRMS.

Feature Summary

• Contains four identical second-order filter sections within a single surface-mount package.
• Provides low noise performance suitable for precision analog signal processing applications.
• Supports flexible filter topologies including lowpass, highpass, bandpass, and notch configurations via external resistor networks.

Applications

• Dual matched fourth-order Butterworth lowpass filters
• Clock-tunable bandpass or bandreject (notch) filters
• Precision instrumentation signal conditioning

Procurement Notes

Verify the specific ordering suffix #TRPBF indicates tape and reel packaging when sourcing components. Confirm that the CG suffix corresponds to the commercial temperature range of 0°C to 70°C. Ensure compatibility with standard 28-lead SSOP footprints during procurement planning.

Selection Notes

Select this component when a fixed 50:1 clock-to-center frequency ratio is required. Compare against other family members like the LTC1068-200 or LTC1068-25 if different tuning ratios are needed. Verify that the 4MHz GBW and 7V/µs slew rate meet the dynamic requirements of the target application.

Part Context

This part belongs to the LTC1068 series of universal switched-capaculator filter building blocks. The series includes variants with different nominal clock-to-center frequency ratios, specifically 200:1, 100:1, 50:1, and 25:1. All variants share the same internal architecture and pinout but differ in their default tuning characteristics.

Replacement Considerations

Direct replacements within the same package and function include the LTC1068-50IG#TRPBF for an extended industrial temperature range (-40°C to 85°C). Other family members such as the LTC1068-200 or LTC1068-25 require circuit redesign due to different clock ratios.

FAQ

What is the maximum clock frequency for the LTC1068-50?

The maximum clock frequency is 3.4 MHz when operating with ±5V supplies and a Q factor less than or equal to 1.6 in Mode 1.

How does the AGND pin behave in single supply operation?

For the LTC1068-50, the analog ground voltage is internally biased to 0.435 times the positive supply voltage (V+).

What is the typical noise level for the LTC1068-50 section?

The typical noise per second-order section with Q ≤ 5 is 75µVRMS.