LTC1569CS8-7#TRPBF

Overview

The LTC1569CS8-7#TRPBF is a 10th-order lowpass filter featuring linear phase and a root raised cosine amplitude response. It operates from single 3V to dual ±5V supplies, supporting cutoff frequencies up to 300kHz on a 5V supply. The device uses a single external resistor to set the internal oscillator frequency, which divides by 1, 4, or 16 via Pin 5 to program the cutoff frequency across seven octaves. Alternatively, an external clock can be applied with a fixed 32:1 ratio. Key electrical parameters include a maximum DC offset of 5mV, 80dB CMRR at DC, and 80dB signal-to-noise ratio at 5V. Power consumption varies based on the divider mode, offering significant savings in divide-by-4 and divide-by-16 configurations.

Feature Summary

• Features a root raised cosine amplitude response suitable for pulse shaping in data communications.
• Provides linear phase characteristics within the passband for I/Q signal processing applications.
• Allows cutoff frequency programming using a single external resistor without requiring an external clock source.
• Supports differential or single-ended input configurations with high common-mode rejection.

Applications

• Data communication filters for 3V operation
• Linear phase and phase matched filters for I/Q signal processing
• Pin programmable cutoff frequency lowpass filters

Procurement Notes

Verify the specific suffix TRPBF indicates tape and reel packaging when sourcing this component. Confirm the manufacturer is Analog Devices Inc. Ensure the order matches the SO-8 surface mount package requirements. Check for any RoHS compliance documentation if required by your manufacturing standards. Validate that the operating temperature range meets your system specifications.

Selection Notes

Select this component when a high-order linear phase response is required for anti-aliasing or pulse shaping. Choose the divide-by-1, 4, or 16 modes based on the desired power consumption versus cutoff frequency trade-off. Ensure the external resistor tolerance aligns with the required cutoff frequency accuracy. Verify that the supply voltage supports the target cutoff frequency range.

Part Context

This part belongs to the LTC1569 family of sampled data filters. It is distinct from other variants like the LTC1569-3 or LTC1569-5 by its specific root raised cosine response and cutoff frequency scaling. The CS8-7 designation identifies the commercial temperature grade and SO-8 package configuration within the broader product line.

Replacement Considerations

Public confirmed substitute part numbers are not available in the provided documentation. Consider evaluating other members of the LTC1569 family or related Linear Technology active filter series if pin compatibility and performance metrics allow for migration.

FAQ

How is the cutoff frequency determined?

The cutoff frequency is set by a single external resistor connected between Pin 6 (RX) and Pin 7 (V+). The internal oscillator frequency is then divided by 1, 4, or 16 depending on the connection state of Pin 5 (DIV/CLK).

What is the maximum DC offset?

The maximum DC offset is specified as 5mV, making it suitable for DC-accurate applications.

Can the filter operate without an external clock?

Yes, the LTC1569-7 features an internal oscillator that can be programmed with a single external resistor, eliminating the need for an external clock source.