SN74LS90D

Counter Dividers Overview

The SN74LS90D is a high-speed 4-bit ripple-type counter from the 74LS series, manufactured by onsemi. It is partitioned into two sections: a divide-by-two and a divide-by-five stage, triggered by HIGH-to-LOW clock transitions. The device supports BCD, bi-quinary, modulo-12, or modulo-16 counting modes when sections are cascaded. It features a 2-input gated Master Reset (Clear) and a 2-input gated Master Set (Preset 9). Key electrical parameters include a typical count rate of 42 MHz, power consumption of 45 mW, and an operating voltage range of 4.75 V to 5.25 V. It operates within a temperature range of 0°C to 70°C in a 14-SOIC package.

Counter Dividers Feature Summary

• Partitioned architecture with separate divide-by-two and divide-by-five sections for flexible configuration.
• Includes dedicated 2-input gated Master Reset and Master Set functions for direct control.
• Supports multiple counting modes including BCD, bi-quinary, modulo-12, and modulo-16.
• Features input clamp diodes to limit high-speed termination effects.

Counter Dividers Applications

• Digital frequency division circuits
• BCD counting applications
• Modulo-N counter designs
• Bi-quinary code generation

Counter Dividers Procurement Notes

Verify the manufacturer designation carefully, as SN74LS90D is a legacy part number historically associated with Texas Instruments but currently listed under onsemi distribution channels. Confirm RoHS compliance status, as some listings indicate non-compliance while others reference compliant variants like SN74LS90DE4. Ensure the specific lot date code aligns with project requirements due to potential end-of-life status.

Counter Dividers Selection Notes

Select this component for applications requiring simple, low-power decimal or binary counting without complex interface logic. The availability of both reset and preset inputs simplifies initialization compared to counters lacking set capabilities. Consider the 42 MHz maximum count rate for speed requirements and verify that the SOIC package fits the board layout constraints.

Counter Dividers Part Context

This device belongs to the standard 74LS logic family, known for low power consumption relative to earlier TTL standards. It is functionally similar to other 74LS counters like the SN74LS93 (divide-by-eight) but offers specific decade counting capabilities. The 'SN' prefix typically denotes commercial grade temperature ranges, distinguishing it from the military-grade '54' series.

Counter Dividers Replacement Considerations

• SN74LS90N
• SN74LS90DE4