FST3245QSC

Overview

The FST3245QSC is an 8-bit bus switch manufactured by onsemi, designed for high-speed CMOS applications with TTL-compatible inputs. It operates within a supply voltage range of 4.0 V to 5.5 V and supports an operating temperature range from -40°C to +85°C. The device features a low on-resistance (RON) of typically 4 Ω at VCC = 4.5 V and minimal propagation delay of 0.25 ns. It utilizes a 20-lead Thin Shrink Small Outline Package (TSSOP).

Feature Summary

• Provides eight-bits of high-speed CMOS bus switching in a standard '245 pin-out.
• Low on-resistance allows inputs to connect to outputs without adding propagation delay or generating additional ground bounce noise.
• Control inputs are compatible with TTL levels.
• Zero bounce operation in flow-through mode.

Applications

• High-speed data transmission systems requiring low latency.
• Bus bridging between different logic families.
• Signal routing in digital communication interfaces.

Procurement Notes

Verify the specific suffix QSC against official ordering information to confirm package type and tape/reel specifications. Ensure compatibility with the required operating temperature range (-40°C to +85°C) and voltage levels (4.0 V to 5.5 V). Confirm that the 20-lead TSSOP package meets your PCB layout constraints.

Selection Notes

Select this component when a low-propagation-delay, 8-bit bidirectional switch is required. It serves as a direct functional replacement for standard '245 devices where lower on-resistance and reduced ground bounce are critical. Ensure input voltages remain within the specified limits relative to VCC.

Part Context

The FST3245 series belongs to the Fast Switch family, offering superior performance over standard logic buffers. It is part of onsemi's portfolio following the integration of Fairchild Semiconductor products. The device maintains backward compatibility with legacy '245 pin-outs while providing enhanced electrical characteristics.

Replacement Considerations

Check for updated part numbers due to Fairchild Semiconductor integration; underscores may be replaced by dashes. Verify if alternative packages like SOIC-20 are available if TSSOP is unsuitable.

FAQ

What is the typical propagation delay of the FST3245?

The typical propagation delay through the switch is 0.25 ns.

How does the FST3245 handle unused control inputs?

Unused control inputs must be held HIGH or LOW; they may not float.