LTC6561HUF#WTRPBF

Overview

The LTC6561HUF#WTRPBF is an automotive-grade, four-channel multiplexed transimpedance amplifier (TIA) from Analog Devices. It features a 220MHz bandwidth and 74kΩ transimpedance gain with a linear input range of 30µA. The device operates on a single 5V supply, consuming 200mW. Key electrical parameters include a 4.8pA/√Hz input current noise density at 200MHz and fast channel switchover under 50ns. Packaged in a compact 4mm × 4mm 24-lead QFN, it supports output multiplexing to expand channel counts for APD arrays.

Feature Summary

• Integrated 4-to-1 input multiplexer combined with an output MUX capability allows multiple devices to be cascaded for scalable multi-channel solutions.
• Fast overload recovery and rapid channel switching minimize data loss and latency in high-speed optical detection systems.
• Low-noise architecture optimized for Avalanche Photodiode (APD) inputs, ensuring high signal fidelity in demanding environments.
• Robust internal protection circuitry enables survival and quick recovery from significant saturation events without phase reversal.

Applications

• LIDAR receivers utilizing Avalanche Photodiodes (APDs)
• Industrial imaging systems requiring low-noise amplification
• Multi-channel APD array interfaces

Procurement Notes

Verify the #W suffix confirms AEC-Q100 qualification for automotive reliability requirements. Confirm the #TRPBF suffix indicates tape and reel packaging rather than tube. Ensure the H grade matches the required -40°C to +125°C operating temperature range for your specific application environment.

Selection Notes

Select this component when designing systems that require multiplexing multiple APD channels into a single output path. Consider the 220MHz bandwidth limit relative to total input capacitance. Evaluate the need for AC versus DC coupling based on dynamic range requirements and switching speed constraints.

Part Context

This part belongs to the LTC6561 family of four-channel TIAs. The HUF package denotes a 24-lead plastic QFN form factor. The W suffix identifies it as an automotive-grade version manufactured under controlled quality standards, distinct from standard commercial variants.

Replacement Considerations

Public confirmed substitute: LTC6561HUF#PBF (Commercial Grade). Verify if automotive qualification is strictly required before substituting with the non-W variant.

FAQ

How does the Output MUX function?

The O_MUX pin controls output isolation. When driven high, it decouples all four inputs from the output, allowing multiple LTC6561 devices to share a common output line in a master/slave configuration.

What is the impact of AC coupling on switching time?

AC coupling introduces a settling glitch during channel selection. The switching time depends on the capacitor value; larger capacitors increase the time required for the TIA input to recharge to the active voltage level.