SN74CBT6800CDBR

Overview

The SN74CBT6800CDBR is a 10-bit TTL-compatible FET bus switch manufactured by Texas Instruments. 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 active undershoot protection on A and B ports up to -2 V, ensuring proper OFF state during signal anomalies. It includes a precharged B port via the BIASV pin to minimize live-insertion noise. The component provides low ON-state resistance (3 Ω typical) and low input/output capacitance (5.5 pF typical). It supports partial-power-down mode via Ioff and withstands latch-up currents exceeding 100 mA per JESD 78 Class II.

Feature Summary

• Active undershoot protection circuitry on A and B ports prevents false switching during negative voltage excursions.
• B-port precharging via user-selectable bias voltage minimizes signal distortion during live insertion and hot-plugging events.
• Supports partial-power-down operation through isolation when powered down, preventing damaging backflow current.
• High ESD performance protects against human-body model and charged-device model electrostatic discharge.

Applications

• PCI interface bus switching
• Memory interleaving systems
• Bus isolation for digital signals
• Low-distortion analog signal gating

Procurement Notes

Verify the specific package marking CT6800C and SSOP-24 physical dimensions against the official mechanical outline drawing. Confirm that the BIASV pin is correctly connected to the target logic threshold voltage to ensure effective glitch reduction during card insertion. Ensure control inputs are pulled to valid logic levels to maintain the high-impedance state during power transitions.

Selection Notes

Select this component when designing systems requiring simultaneous switching of ten parallel data lines with minimal signal degradation. The device is suitable for applications demanding low capacitance to preserve signal integrity at high speeds. Consider the BIASV pin configuration if the application involves frequent hot-plugging or requires specific noise immunity thresholds for the receiving logic gates.

Part Context

This part belongs to the Widebus family of high-speed bus switches from Texas Instruments. It is designed to replace discrete transistor solutions in multi-bit bus architectures. The SN74CBT6800CDBR variant specifically utilizes an SSOP-24 package, offering a compact footprint for surface-mount assembly while maintaining the electrical characteristics of the broader SN74CBT6800C series.

Replacement Considerations

SN74CBT6800CDW

FAQ

How does the BIASV pin function during hot-plugging?

The BIASV pin precharges the B port to a user-defined voltage level when the switch is off. This ensures that any glitch caused by parasitic capacitance during insertion does not cross the input threshold of the receivers, thereby minimizing live-insertion noise.

What is the purpose of the Ioff feature?

The Ioff feature allows the device to support partial-power-down mode. It ensures that no damaging current flows back through the device's I/O pins when the device is powered down but the system bus remains active.