DM74ALS245AMSAX

Overview

The DM74ALS245AMSAX is an octal 3-state bus transceiver manufactured by onsemi, utilizing the Advanced Low-power Schottky (ALS) logic family. It operates within a supply voltage range of 4.5V to 5.5V and supports a maximum operating temperature of 70°C. The device features non-inverting outputs with low output impedance capable of driving terminated transmission lines up to 133Ω. Propagation delay times are specified between 0ns and 31ns, while output enable and disable times range from 2ns to 20ns depending on the transition direction.

Feature Summary

• Advanced oxide-isolated, ion-implanted Schottky TTL process for high-speed performance
• Glitch-free bus operation during power-up and power-down sequences
• Independent 3-state control for A and B buses via dedicated enable inputs
• Designed to interface directly with CMOS devices at specified voltage levels

Applications

• Memory systems requiring bidirectional data transfer
• Microprocessor systems utilizing asynchronous bidirectional data buses
• Driving terminated transmission lines in digital communication circuits

Procurement Notes

Verify that the component matches the specific SSOP-20 package configuration associated with the AMSA ordering code. Confirm the manufacturer origin, as this part was originally produced by Fairchild Semiconductor before acquisition by onsemi. Ensure the datasheet revision aligns with your design requirements, specifically checking switching characteristics under your target load conditions.

Selection Notes

Select this component when designing systems requiring robust, high-speed bidirectional data routing with minimal loading effects. The ALS technology offers a balance of speed and power consumption suitable for standard TTL and CMOS environments. Consider the 3-state capability for managing multiple bus masters or preventing signal contention on shared data lines.

Part Context

This device belongs to the 74ALS series of standard logic integrated circuits. It functions as an octal bus transceiver, providing eight independent channels for data transmission. The 'AMSAX' suffix indicates the Shrink Small Outline Package (SSOP) variant supplied in tape and reel format for automated assembly processes.

Replacement Considerations

SN74ALS245AN

FAQ

How is the direction of data transmission controlled?

Data transmission direction is controlled by the DIR input pin. When DIR is LOW, data flows from the A bus to the B bus; when DIR is HIGH, data flows from the B bus to the A bus.

What happens when the G input is HIGH?

When the G input is HIGH, both the driver and receiver outputs enter a high-impedance mode, effectively isolating the A and B buses from each other.