MC74HCT125ADR2G

Overview

The MC74HCT125ADR2G is a quad 3-state noninverting buffer manufactured by onsemi. It belongs to the high-performance silicon-gate CMOS HCT logic family, designed for bus-oriented systems. The device features four independent outputs with active-low enable controls. It operates within a supply voltage range of 4.5 V to 5.5 V and supports an operating temperature from -55°C to +125°C. The component is housed in a 14-pin SOIC package.

Feature Summary

• Provides direct interface capability to standard CMOS or TTL outputs without requiring pullup resistors.
• Features four separate output enables that are active-low for precise control of data flow.
• Designed specifically for use as 3-state memory address drivers and clock drivers.
• Delivers high noise immunity characteristic of CMOS devices while maintaining compatibility with LSTTL loads.

Applications

• 3-state memory address drivers
• Clock drivers
• Bus-oriented systems

Procurement Notes

Verify the specific ordering suffix 'R2G' corresponds to the tape and reel packaging format required for automated assembly processes. Confirm that the device code matches the HCT series specifications rather than the HC series, as input thresholds differ significantly between these families. Ensure the package type aligns with the design footprint requirements.

Selection Notes

Select this component when interfacing with standard CMOS or TTL outputs is required, as it eliminates the need for external pullup resistors unlike the HC variant. Choose this part for applications demanding operation within the strict 4.5 V to 5.5 V supply range. Consider the active-low enable functionality if system logic requires low-active control signals for bus arbitration.

Part Context

This component is part of the MC74HC125A/MC74HCT125A family, which shares identical pinouts with LS125 and LS126 devices. While functionally similar to the HC series, the HCT version offers distinct input threshold characteristics compatible with standard TTL logic levels. The R2G suffix indicates the specific reel packaging configuration used for surface-mount manufacturing.

Replacement Considerations

MC74HC125ADR2G

FAQ

How does the input compatibility of the MC74HCT125A differ from the MC74HC125A?

The MC74HCT125A inputs are directly compatible with standard CMOS or TTL outputs. In contrast, the MC74HC125A inputs are compatible with standard CMOS outputs but require pullup resistors to achieve compatibility with LSTTL outputs.

What is the state of the outputs when the enable pin is inactive?

When the active-low output enable (OE) pin is held high, the outputs enter a high-impedance state, effectively disconnecting them from the circuit.