SN74CBT6845CRGYR

Overview

The SN74CBT6845CRGYR is an 8-bit FET bus switch in a 20-pin VQFN package. It operates with a supply voltage (VCC) ranging from 4 V to 5.5 V and supports bidirectional data flow between A and B ports. The device features low ON-state resistance (ron), typically 3 Ω at VCC = 4.5 V, and low input/output capacitance of 5.5 pF typical when OFF. It includes active undershoot protection for off-isolation on A and B ports up to -2 V. The B port outputs are precharged by a bias voltage (BIASV) to minimize signal distortion during live insertion and hot-plugging.

Feature Summary

• Active undershoot-protection circuitry provides protection for undershoot up to -2 V on the A and B ports.
• B-port outputs are precharged via a user-selectable bias voltage (BIASV) to minimize live-insertion noise.
• Supports partial-power-down mode operation using Ioff to prevent damaging backflow current.
• Data and control inputs provide undershoot clamp diodes.

Applications

• PCI interface
• Memory interleaving
• Bus isolation
• Low-distortion signal gating

Procurement Notes

Verify the specific ordering suffix 'RGYR' corresponds to the VQFN package and tape-and-reel quantity. Confirm that the component meets RoHS compliance standards and lead finish specifications required for your assembly process. Ensure the operating temperature range aligns with your system's thermal environment.

Selection Notes

Select this component for applications requiring high-speed switching with minimal propagation delay. The device is suitable for systems needing support for multiple signaling levels including 0.8-V, 1.2-V, 1.5-V, 1.8-V, 2.5-V, 3.3-V, and 5-V. Control inputs can be driven by TTL or 5-V/3.3-V CMOS outputs.

Part Context

This part belongs to the SN74CBT6845C series of high-speed TTL-compatible FET bus switches. It is designed to allow for minimal propagation delay while maintaining low power consumption. The device is manufactured by Texas Instruments and is available in various packages including TSSOP, SSOP, and VQFN.

Replacement Considerations

SN74CBT6845CPWR

FAQ

How does the device handle live insertion?

The B port is precharged to a user-selectable bias voltage (BIASV) through an equivalent 10-kΩ resistor when OE is high or if the device is powered down. This minimizes glitching effects caused by parasitic capacitance during card insertion or removal.

What is the function of the Ioff feature?

The Ioff feature ensures that damaging current will not backflow through the device when it is powered down, supporting partial-power-down mode operation.