SN74CBT3245AZQNR

Overview

The SN74CBT3245AZQNR is an octal FET bus switch manufactured by Texas Instruments. It provides eight bits of high-speed TTL-compatible bus switching in a 20-pin VFBGA (ZQN) package. The device operates with a supply voltage range of 4V to 5.5V and supports an operating temperature range from -40°C to +85°C. Key electrical characteristics include a maximum on-state resistance of 15Ω at VCC=5V, a propagation delay of 0.25ns at VCC=5V, and low off-state leakage current.

Feature Summary

• Provides eight bits of high-speed bus switching with standard '245-type pinout compatibility.
• Features low on-state resistance for minimal signal path delay between ports.
• Supports TTL-compatible input levels for direct interfacing with logic systems.
• Includes powered-off protection to prevent excessive current draw during power-up or power-down.

Applications

• High-speed data bus switching applications
• Portable equipment requiring low power consumption
• Consumer electronics utilizing 5V logic interfaces

Procurement Notes

Verify the specific ZQN package variant matches the required footprint and thermal specifications. Confirm that the 4V to 5.5V supply voltage range aligns with the system design. Ensure the -40°C to +85°C industrial temperature rating meets environmental requirements. Check for RoHS compliance status if restricted substances are a concern.

Selection Notes

Select this component when an octal bidirectional bus switch is needed with standard '245 pinout compatibility. It is suitable for designs requiring low on-resistance and fast switching speeds within a 5V logic environment. Consider the VFBGA package constraints for PCB layout and thermal management compared to other available packages like TSSOP or SOIC.

Part Context

This part belongs to the SN74CBT3245A family of octal FET bus switches. It shares functional similarities with other variants in the series but differs in packaging. The ZQN suffix indicates a 20-pin VFBGA package, distinguishing it from leaded options like DW (SOIC) or PW (TSSOP). All variants maintain the same core electrical performance and pinout configuration.

Replacement Considerations

SN74CBT3245AGQNR is a confirmed substitute offering identical functionality in a GQN package variant.

FAQ

How does the OE pin control the switch state?

When the output-enable (OE) input is low, the switch connects port A to port B. When OE is high, the switch disconnects the ports, placing them in a high-impedance state.

What is the purpose of the pull-up resistor on the OE pin?

To ensure a high-impedance state during power-up or power-down, the OE pin should be tied to VCC through a pull-up resistor. This prevents unintended conduction while the supply voltage is rising.