SN74AS280NSR

Overview

The SN74AS280NSR is a universal 9-bit parity generator/checker from the Texas Instruments AS logic series. It features nine data inputs (A through I) and provides both Σ EVEN and Σ ODD outputs to support either parity scheme. The device utilizes advanced Schottky circuitry for high performance, with a supply voltage range of 4.5 V to 5.5 V. Propagation delays are specified between 3 ns and 12 ns depending on the output type. It operates within an ambient temperature range of 0°C to 70°C and is housed in a 14-pin Small-Outline Package (SOIC).

Feature Summary

• Generates or checks parity for nine data lines simultaneously.
• Provides dedicated outputs for both odd and even parity configurations.
• Inputs are buffered to reduce drive requirements.
• Capable of cascading to expand word-length capability up to 81 bits.

Applications

• Data transmission systems requiring error detection via parity checking.
• Memory subsystems utilizing parity generation for data integrity verification.
• System upgrades replacing legacy MSI parity circuits like the SN74ALS180.

Procurement Notes

Verify that the specific orderable part number matches the required package style and tape-and-reel specifications. Confirm the operating temperature range aligns with the system environment. Ensure input buffering characteristics meet the driving source capabilities. Check for any recent product change notifications regarding pinout or electrical parameters before finalizing procurement.

Selection Notes

Select this component when a high-speed 9-bit parity solution is required within standard 5-V logic families. The buffered inputs simplify interfacing with multiple drivers. Consider cascading options if the application requires handling data words longer than nine bits. Verify that the SOIC package dimensions fit the available board space constraints.

Part Context

This device belongs to the Texas Instruments SN74AS family, which employs Advanced Schottky technology to deliver faster switching speeds compared to standard LS or ALS logic. The SN74AS280 serves as a functional replacement for older parity generators while offering improved performance metrics. It is designed for use in digital systems where reliable data transmission and integrity checking are critical.

Replacement Considerations

The datasheet explicitly states that the SN74AS280 can be substituted for the SN74ALS180 and SN74AS180 in existing designs. This substitution maintains identical functionality despite the absence of expander inputs on the newer devices, as the function is provided by terminal 4.