FST3125QSC

Overview

The FST3125QSC is a digital bus switch IC manufactured by Fairchild Semiconductor, featuring four high-speed CMOS TTL-compatible switches. It operates within an extended temperature range of -40°C to +85°C and utilizes a 16-pin SSOP package (SSOP16, .25). The device provides low on-resistance for minimal propagation delay and ground bounce noise. Control inputs are compatible with TTL levels, allowing independent switching via separate /OE pins.

Feature Summary

• Provides four independent one-bit switches connecting Port A to Port B when enabled
• Low on-resistance minimizes signal degradation without adding propagation delay
• Control inputs are fully compatible with standard TTL logic levels
• Operates in flow-through mode with zero bounce characteristics

Applications

• Signal and control switching in data processing systems
• Voltage translation between 5V and 3.3V domains
• Bus isolation for mass storage and workstation interfaces
• Clock gating applications requiring low noise

Procurement Notes

Verify the manufacturer origin as Fairchild Semiconductor, noting that onsemi may list similar parts due to corporate acquisition history. Confirm the specific SSOP-16 package code matches the required footprint. Ensure the component meets RoHS compliance standards if required by the design specification. Check for any product change notices regarding assembly locations or material updates.

Selection Notes

Select this component when low propagation delay and minimal ground bounce are critical requirements. The individual active-low enable inputs allow precise control over each bit path. Verify that the system voltage levels align with the TTL-compatible input specifications. Consider the thermal operating range limits for the intended application environment.

Part Context

This part belongs to the FST3125 family of high-speed CMOS bus switches. It derives from Fairchild's proven switch technology previously utilized in products like the FST3384. The family emphasizes low power consumption and capacitance reduction for high-performance digital interfaces.

Replacement Considerations

Public confirmed substitute part numbers are not available in the provided documentation.