SN74CBT16811CDGVR

Overview

The SN74CBT16811CDGGR is a high-speed TTL-compatible FET bus switch from the Widebus family, housed in a 56-pin TSSOP package. It integrates two independent 12-bit bus switches or functions as a single 24-bit switch. The device operates on a single supply voltage ranging from 4 V to 5.5 V and supports bidirectional data flow with near-zero propagation delay. Key electrical characteristics include a typical ON-state resistance of 3 Ω and low input/output capacitance of 5.5 pF. It features active undershoot protection up to -2 V and precharges B-port outputs via a user-selectable bias voltage (BIASV) to minimize live-insertion noise.

Feature Summary

• Active undershoot-protection circuitry on A and B ports ensures proper OFF state during signal dips down to -2 V.
• B-port outputs are precharged by a user-selectable bias voltage (BIASV) to minimize signal distortion during live insertion and hot-plugging.
• Supports partial-power-down mode operation through Ioff feature, preventing damaging backflow current when powered down.
• Data and control inputs provide undershoot clamp diodes for enhanced signal integrity.

Applications

• PCI interface applications supporting hot-plug operations
• Memory interleaving systems requiring bus isolation
• Low-distortion signal gating in digital and analog circuits

Procurement Notes

Verify that the ordering suffix 'DGGR' corresponds to the tape-and-reel packaging format. Confirm the operating temperature range matches the application requirements of -40°C to 85°C. Ensure the design accommodates the 56-pin TSSOP footprint and adheres to the recommended operating conditions for VCC and BIASV voltages.

Selection Notes

Select this component when designing systems requiring high-density bus switching with minimal signal degradation. The dual 12-bit configuration offers flexibility for both parallel data buses and isolated channel management. Consider the BIASV pin functionality if the application involves frequent card insertion or removal where glitch minimization is critical.

Part Context

This part belongs to Texas Instruments' Widebus family of high-speed FET bus switches. It is designed to replace older logic families in high-performance digital systems. The SN74CBT16811C variant provides specific enhancements like undershoot protection compared to standard bus switches, making it suitable for modern high-speed interfaces.

Replacement Considerations

Public confirmed substitute part numbers: SN74CBT16211CDGGR, SN74CBTD16211DGGR, SN74CBTS16211DGGR, FST16211MTDX.

FAQ

How does the device handle live insertion events?

The B-port outputs are precharged to a user-selectable bias voltage (BIASV) when the switch is off. This minimizes live-insertion noise by ensuring glitches do not cross the input threshold region of receivers on the active bus.

What is the function of the Ioff feature?

The Ioff feature supports partial-power-down mode operation. It ensures that damaging current will not backflow through the device when it is powered down, providing isolation during power-off states.