LTC1563-3IGN#PBF

Overview

The LTC1563-3IGN#PBF is a fourth-order active RC lowpass filter in a 16-lead SSOP package. It provides a unity-gain Bessel response using a single external resistor, with cutoff frequencies ranging from 256Hz to 256kHz. The device operates on a single 3V supply or dual ±5V supplies, featuring rail-to-rail inputs and outputs. Key electrical parameters include a typical DC offset of 1mV, power supply current of 8mA to 14mA in high-speed mode, and noise levels of 36µVRMS at 25.6kHz. It supports cascading for eighth-order filtering and includes a shutdown mode.

Feature Summary

• Provides a unity-gain Bessel transfer function via a single external resistor value
• Features rail-to-rail input and output voltage swing capabilities
• Includes a low-power operating mode that reduces supply current significantly
• Supports cascading two sections to form an eighth-order lowpass filter

Applications

• Antialiasing filters for data acquisition systems
• Smoothing or reconstruction filters in signal processing chains
• Linear phase filtering applications in data communication equipment
• Phase locked loops requiring specific phase characteristics

Procurement Notes

Verify the #PBF suffix indicates lead-free compliance and RoHS adherence before procurement. Confirm the IGN suffix corresponds to the industrial temperature range (-40°C to 85°C). Ensure the narrow SSOP-16 footprint matches the target PCB design constraints. Cross-reference the manufacturer's latest documentation for any updates regarding material declarations or end-of-life status.

Selection Notes

Select this component when a Bessel response is required for linear phase performance. Use the formula R = 10k(256kHz/fC) to determine the necessary external resistor for the desired cutoff frequency. Consider the Low Power mode if system power consumption is critical for lower frequency applications. Verify that the load impedance remains above 10kΩ to maintain optimal output swing and distortion specifications.

Part Context

This part belongs to the LTC1563 family of active RC filters, which also includes the LTC1563-2 offering a Butterworth response. Both variants share identical pinouts and operational modes but differ in their internal pole placement to achieve distinct frequency responses. The family is designed to replace discrete RC networks with simplified external component requirements.

Replacement Considerations

The LTC1563-2IGN#PBF serves as a functional substitute if a Butterworth response is acceptable instead of Bessel. Other members of the LTC1563 family may be considered if different gain configurations or response types are required. Verify that any replacement maintains the same SSOP-16 package dimensions and electrical interface compatibility.

FAQ

How is the cutoff frequency determined for the LTC1563-3?

The cutoff frequency is set by a single external resistor using the formula R = 10k(256kHz/fC), where fC is the desired cutoff frequency.

What is the purpose of the EN pin?

The EN pin controls the shutdown state. Pulling it low enables normal operation, while leaving it open or driving it high activates a low-power shutdown mode.

Can the LTC1563-3 be used for gains greater than unity?

Yes, by utilizing different valued resistors for the filter network, gain and other transfer functions can be achieved, though this requires more complex calculations than the standard unity-gain setup.