SN74CB3Q16811DLR

Overview

The SN74CB3Q16811DLR is a 24-bit FET bus switch from the Widebus family, packaged in a 56-pin SSOP. It operates on a supply voltage (VCC) ranging from 2.3 V to 3.6 V and supports data I/O levels up to 5.5 V. The device features low ON-state resistance (ron), typically 5 Ω at VCC = 2.5 V, with a maximum of 9 Ω. Propagation delay (tpd) is between 0.09 ns and 0.15 ns. It includes precharged B-port outputs via a bias voltage (BIASV) pin to minimize signal distortion during live insertion.

Feature Summary

• Supports partial-power-down mode through dedicated Ioff circuitry that prevents damaging current backflow when the device is powered down.
• Features precharged B-port outputs driven by an external bias voltage to minimize signal distortion and glitches during hot plugging or live insertion events.
• Utilizes a charge pump mechanism to elevate gate voltage, ensuring low and flat ON-state resistance for rail-to-rail switching across the data ports.

Applications

• PCI Hot Plug applications
• Hot Docking systems
• Memory Interleaving
• Bus Isolation

Procurement Notes

Verify the specific package suffix 'DLR' corresponds to the SSOP-56 tape and reel configuration as listed in the ordering information. Confirm that the design accommodates the required BIASV pin connection for precharging functionality. Ensure control inputs are properly biased to maintain the high-impedance state during power transitions.

Selection Notes

Select this component for high-bandwidth interfaces requiring bidirectional data flow with near-zero propagation delay. It is suitable for broadband communications and networking where low capacitive loading (Cio(OFF) = 4 pF typ) is critical. The device is appropriate for systems needing 5-V tolerant I/Os while operating at lower core voltages.

Part Context

This part belongs to the Texas Instruments SN74CB3Q16811 series, which is equivalent to IDT QS3VH bus switches. It is designed as a high-performance solution for digital and analog applications, offering optimized interface capabilities for data-intensive computing systems compared to standard logic switches.

Replacement Considerations

The datasheet states that SN74CB3Q Bus Switches are equivalent to IDTQS3VH Bus Switches. Verify pinout compatibility and electrical specifications before substituting with IDT equivalents.

FAQ

How does the device handle live insertion noise?

The B-port outputs are precharged to a bias voltage (BIASV) equal to the input threshold voltage of the receivers on the active bus. This ensures that glitches produced during card insertion do not cross the input threshold region, minimizing live-insertion noise effects.

What is the function of the Ioff feature?

The Ioff circuitry supports partial-power-down operation by preventing damaging current backflow through the device when it is powered down (VCC = 0 V).