MC74HC244AF

Overview

The MC74HC244AF is an octal 3-state non-inverting buffer and line driver manufactured by onsemi. It operates within a supply voltage range of 2.0 V to 6.0 V. The device features two active-low output enables controlling eight independent channels. Propagation delay varies from 15 ns at 6.0 V to 96 ns at 2.0 V. Maximum quiescent supply current is 4 µA at 6.0 V. Input leakage current is limited to ±1.0 µA. Output drive capability supports up to 15 LSTTL loads.

Feature Summary

• Octal configuration with dual active-low output enables for bus-oriented systems
• Non-inverting outputs directly interface to CMOS, NMOS, and TTL logic families
• High noise immunity characteristics inherent to CMOS technology
• Compatible with standard CMOS outputs and LSTTL outputs when pullup resistors are used

Applications

• Memory address drivers
• Clock drivers
• Bus-oriented systems

Procurement Notes

Verify the specific suffix (e.g., DWG, DTG) against the required package type, as the base model number does not specify the physical housing. Confirm RoHS compliance status and lead-free marking requirements for the manufacturing lot. Ensure the ordering quantity matches the specified shipping unit, such as rails or tape and reel quantities, to avoid packaging discrepancies during procurement.

Selection Notes

Select this component for applications requiring high-speed buffering with low power consumption. The HC series offers a wider operating voltage range compared to HCT variants. Verify that the input voltage levels match the source logic family, utilizing pullup resistors if interfacing with LSTTL outputs. Ensure the thermal dissipation capabilities of the chosen package meet the system's power requirements under maximum load conditions.

Part Context

This device belongs to the 74HC logic family, representing High-Speed CMOS technology. It serves as the non-inverting counterpart to the 74HC240. The pinout is identical to the LS244, facilitating direct upgrades in existing designs. The component is designed for general-purpose digital buffering and line driving tasks in commercial and industrial electronics.

Replacement Considerations

MC74HCT244A

FAQ

How do the output enable pins function?

The Enable A and Enable B pins are active-low. When a low level is applied, the corresponding outputs are enabled and function as non-inverting buffers. When a high level is applied, the outputs assume a high-impedance state.

What is the input compatibility for the HC variant?

The MC74HC244A inputs are compatible with standard CMOS outputs. With pullup resistors, they are also compatible with LSTTL outputs.