SN74CBT16811CDLR

Overview

The SN74CBT16811CDLR is a high-speed TTL-compatible FET bus switch from the Widebus family, organized as two independent 12-bit switches or one 24-bit switch. It operates within a supply voltage range of 4 V to 5.5 V and supports bidirectional data flow with near-zero propagation delay. The device features low ON-state resistance (3 Ω typical) and low input/output capacitance (5.5 pF typical). It includes active undershoot protection up to -2 V on A and B ports and precharges the B port via a user-selectable bias voltage (BIASV) to minimize live-insertion noise. The component is housed in a 56-pin SSOP package.

Feature Summary

• Active undershoot protection circuitry ensures proper OFF state during signal glitches down to -2 V.
• B-port outputs are precharged by a bias voltage to minimize signal distortion during live insertion and hot-plugging.
• Supports partial-power-down mode operation using Ioff feature to prevent damaging backflow current.
• Data and control inputs provide undershoot clamp diodes for enhanced signal integrity.

Applications

• PCI interface applications supporting PCI Hot Plug
• Memory interleaving systems
• Bus isolation circuits
• Low-distortion signal gating

Procurement Notes

Verify the specific ordering suffix 'CDLR' corresponds to the SSOP-56 tape and reel packaging configuration. Confirm that the operating temperature range meets the application requirements of -40°C to +85°C. Ensure that the BIASV pin is properly connected to manage the precharge function for the intended use case.

Selection Notes

Select this component when designing systems requiring high-speed bidirectional switching with minimal signal degradation. It is suitable for applications needing support for multiple signaling levels ranging from 0.8 V to 5 V. Consider its low power consumption and latch-up performance exceeding 100 mA per JESD 78 Class II standards.

Part Context

This part belongs to the SN74CBT16811C series within Texas Instruments' Widebus family. It is designed as a high-performance alternative to standard logic switches, offering superior speed and lower capacitance. The device integrates specialized features like undershoot protection and bias precharging to address challenges in high-density digital and analog signal routing.

Replacement Considerations

SN74CBT16811CDGGR is a parameter-equivalent replacement available in TSSOP-56 packaging.

FAQ

How does the device handle live insertion events?

The B port is precharged to a user-selectable bias voltage (BIASV) through an equivalent 10-kΩ resistor when OE is high. This minimizes live-insertion noise by ensuring glitches do not cross the receiver input threshold region.

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.