74HCT244D

Overview

The Toshiba 74HCT244D is an octal bus driver belonging to the HCT logic family, designed for 5V CMOS applications. It features eight non-inverting outputs organized into two groups of four, each controlled by a separate output enable input. The device operates within a supply voltage range of 4.5V to 5.5V and supports TTL-compatible input levels. Key electrical parameters include a propagation delay of 41 ns, a maximum low-level output current of 6 mA, and a maximum high-level output current of -6 mA. It is housed in a 20-pin SOP package.

Feature Summary

• Provides eight non-inverting buffer channels with independent control over two groups of four outputs via dedicated enable inputs.
• Features three-state outputs that enter a high-impedance state when disabled, allowing safe bus sharing and isolation.
• Accepts TTL-compatible input voltage levels, enabling direct interfacing with 5V TTL devices without additional level shifting.

Applications

• Bus-oriented memory and address drivers
• Clock drivers and buffer circuits
• TTL-to-CMOS level translation interfaces

Procurement Notes

Verify the manufacturer designation on the component marking, as the '74HCT244D' part number is widely used across multiple vendors including Texas Instruments and NXP. Confirm the specific datasheet version from Toshiba Semiconductor and Storage to ensure accurate timing and electrical characteristics. Check RoHS compliance status and moisture sensitivity levels before integration into the assembly process.

Selection Notes

Select this component when a standard octal buffer with TTL input compatibility is required for 5V systems. The HCT series offers faster switching speeds than LS equivalents while maintaining TTL noise margins. Ensure the application does not require higher drive currents or lower power consumption, in which case HC or AHC series alternatives might be more suitable.

Part Context

This device is part of the industry-standard 74HCT logic family, which bridges the performance gap between older bipolar TTL technologies and modern CMOS solutions. The 'D' suffix indicates a plastic small-outline package (SOP). As an octal buffer, it consolidates eight signal paths into a single integrated circuit, reducing board space compared to discrete logic gates.

Replacement Considerations

Cross-reference with SN74HCT244DWR (Texas Instruments) or MC74HCT244ADWG (onsemi) for pin-compatible alternatives. Verify that substitute parts meet the same 4.5V–5.5V operating voltage and 41 ns propagation delay specifications to maintain system timing integrity.