DM74ALS540ASJ

Overview

The DM74ALS540ASJ is an octal inverting buffer and line driver featuring 3-STATE outputs, manufactured by onsemi. It utilizes an advanced oxide-isolated, ion-implanted Schottky TTL process to ensure switching performance across the full temperature and VCC supply range. The device operates within a recommended supply voltage of 4.5V to 5.5V and supports a free-air operating temperature from 0°C to +70°C. Key electrical characteristics include a maximum propagation delay of 12ns (LOW-to-HIGH) and 9ns (HIGH-to-LOW), with output drive currents of -15mA (HIGH) and 24mA (LOW).

Feature Summary

• Features a data flow-thru pinout arrangement where all inputs are located on the opposite side of the package from the outputs.
• Incorporates P-N-P inputs designed to reduce DC loading on driving circuits.
• Utilizes a 2-input NOR gate for 3-STATE control, placing all eight outputs in a high impedance state if either control input is HIGH.

Applications

• Memory map addressing systems
• Clock drivers
• Bus-oriented transmissions

Procurement Notes

Verify that the specific ordering code matches the required package type, as the ASJ suffix denotes a 20-Lead Small Outline Package (SOP). Confirm compatibility with existing PCB footprints corresponding to the EIAJ TYPE II standard. Ensure design requirements align with the specified logic family and voltage ranges before finalizing procurement decisions.

Selection Notes

Select this component when a bidirectional bus interface or octal buffering solution is required with minimal board space constraints due to the through-package layout. Consider the ALS logic family for its balance of speed and power consumption compared to standard TTL. Verify that the 3-STATE control logic meets system timing requirements for enable and disable transitions.

Part Context

This device belongs to the DM74ALS series of logic integrated circuits. It is functionally compatible with other devices in the ALS family, such as the DM74ALS240A, though it offers a distinct pinout configuration. The part is produced under the Fairchild Semiconductor brand, which has since been acquired by onsemi.

Replacement Considerations

DM74ALS240A

FAQ

How does the 3-STATE control mechanism operate?

The 3-STATE control is implemented via a 2-input NOR gate. If either control input G1 or G2 is at a HIGH logic level, all eight outputs enter a high impedance state.

What is the significance of the data flow-thru pinout?

The data flow-thru pinout places all inputs on one side of the package and all outputs on the opposite side, which greatly enhances printed circuit board layout efficiency.