SN74CBT16811CDL

Overview

The SN74CBT16811CDL 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 VCC range of 4V to 5.5V and supports data I/O signaling levels from 0V to 5.5V. The device features low ON-state resistance (ron) for minimal propagation delay and includes active undershoot protection on A and B ports up to -2V. It incorporates a precharged B port 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.
• B-port outputs are precharged by a bias voltage (BIASV) to minimize signal distortion during live insertion and hot-plugging.
• Supports partial-power-down mode operation using Ioff feature to prevent damaging backflow current.
• Bidirectional data flow with near-zero propagation delay characteristics.

Applications

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

Procurement Notes

Verify that the DL package designation corresponds to the SSOP form factor when sourcing. Confirm the operating temperature range matches the application requirements of -40°C to 85°C. Ensure control inputs are tied to VCC or GND to maintain proper device operation. Check datasheet specifications for thermal impedance values relevant to the specific PCB layout and ambient conditions.

Selection Notes

Select this component for designs requiring wide-voltage translation between 0V and 5.5V domains while maintaining a single 4V to 5.5V supply. The device is suitable for applications demanding low loading due to its low input/output capacitance. Consider the separate output-enable inputs if independent control of the two 12-bit sections is required rather than a unified 24-bit switch.

Part Context

This part belongs to Texas Instruments' Widebus family of high-speed bus switches. It is designed to provide low ON-state resistance and fast switching speeds. The SN74CBT16811C variant specifically addresses live-insertion noise through bias voltage precharging and offers robust protection against undershoot events on the data ports.

Replacement Considerations

SN74CBT16811CDGGR is an equivalent part number in the TSSOP-56 package offering tape-and-reel packaging instead of the tube-packaged SSOP-DL format.

FAQ

How does the device handle live-insertion noise?

The B port is precharged to a user-selectable bias voltage (BIASV) through an equivalent 10-kΩ resistor when OE is high or the device is powered down. This minimizes glitches 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 (VCC = 0 V), providing isolation during partial-power-down applications.