DM74ALS244AMSA

Overview

The onsemi DM74ALS244AMSA is an octal 3-STATE bus driver utilizing Advanced Low-power Schottky (ALS) TTL technology. It features two independent groups of four buffers with separate enable controls, allowing flexible bidirectional or unidirectional data flow in memory and microprocessor systems. The device operates within a supply voltage range of 4.5V to 5.5V and guarantees performance across the extended temperature grade from -40°C to +85°C. Propagation delay is specified between 3ns and 10ns at VCC = 4.5V to 5.5V with a 50pF load. It provides high output drive capability with low power dissipation.

Feature Summary

• Advanced oxide-isolated ion-implanted Schottky process for improved switching speed and reduced power consumption compared to standard LS counterparts.
• Integrated 3-STATE control circuitry that maintains outputs in a high-impedance state during power supply ramp-up or ramp-down to prevent bus glitching.
• PNP input design structure reduces input loading while maintaining functional and pin compatibility with 74LS logic families.

Applications

• Memory system bus interfaces
• Microprocessor system data routing
• Communication system signal buffering

Procurement Notes

Verify the specific ordering code suffix against current manufacturer documentation to confirm package type and tape/reel availability. Confirm the active status of the component as legacy products may have limited production runs. Ensure the selected variant meets the required operating temperature range specifications for the intended application environment.

Selection Notes

Select this component when designing systems requiring high-speed data transfer with minimal power consumption. The dual-group enable architecture supports complex bus topologies. Verify that the 500Ω and 50pF load specifications align with the transmission line requirements of the target interface.

Part Context

This part belongs to the DM74ALS244A family of octal 3-STATE bus drivers manufactured by Fairchild Semiconductor, now part of onsemi. The 'MSA' suffix specifically denotes the 20-Lead Shrink Small Outline Package (SSOP). This series is designed to replace older 74LS devices in applications demanding faster switching speeds and lower power usage.

Replacement Considerations

Direct substitutes include SN74ALS244CDBR from Texas Instruments.

FAQ

How does the device handle power transitions?

The 3-STATE circuitry includes a feature that keeps buffer outputs in a high-impedance state during power supply ramp-up or ramp-down, eliminating bus glitching problems.

What is the propagation delay specification?

Propagation delay time (tPLH/tPHL) is specified between 3ns and 10ns when VCC is between 4.5V and 5.5V with a 50pF load.