LTC1068-50CG#PBF

Overview

The LTC1068-50CG#PBF is a clock-tunable, quad second-order switched-capacitor filter building block in a 28-pin 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 from 3.14V to ±5.5V and operates within a temperature range of 0°C to 70°C. Key electrical parameters include a typical power supply current of 4.5mA at single 5V operation, a gain-bandwidth product of 4MHz, and a slew rate of 7V/µs. Noise performance is specified at 75µVRMS for Q ≤ 5.

Feature Summary

• Contains four identical second-order filter sections within a single surface-mount package
• Clock-tunable architecture allows center frequency adjustment via external clock source
• Supports multiple filter topologies including lowpass, highpass, bandpass, and notch configurations
• Operates with dual supplies, single 5V supply, or single 3.3V supply

Applications

• Designing dual matched fourth-order Butterworth lowpass filters
• Constructing eighth-order universal lownoise filter building blocks
• Implementing clock-tunable bandpass or bandreject (notch) filters

Procurement Notes

Verify the component matches the Analog Devices Inc. manufacturer identification and the specific model number LTC1068-50CG#PBF. Confirm the package type is a 28-lead plastic SSOP and that the suffix #PBF indicates lead-free finish compliance. Ensure the operating temperature range corresponds to the CG variant, which is rated for commercial temperatures between 0°C and 70°C.

Selection Notes

Select this part when a fixed 50:1 clock-to-center frequency ratio is required. Compare against the LTC1068 series variants based on desired frequency ranges; the -50 version supports lowpass/highpass frequencies from 2Hz to 50kHz and bandpass/notch frequencies from 2Hz to 30kHz. Consider the internal op amp specifications, such as the 4MHz GBW and 7V/µs slew rate, for signal integrity requirements.

Part Context

This component belongs to the LTC1068 family of universal switched-capacitor filters. Other members include the LTC1068-200, LTC1068, and LTC1068-25, which differ primarily in their internal clock-to-center frequency ratios of 200:1, 100:1, and 25:1 respectively. All variants share similar pinouts and architectural features but are optimized for different frequency scaling applications.

Replacement Considerations

Publicly confirmed substitute part numbers are not available in the provided documentation. Designers should consult Analog Devices marketing for customized versions or alternative families if exact replacement is necessary.