74F191SJ

Overview

The Fairchild Semiconductor 74F191SJ is a synchronous up/down binary counter belonging to the F/FAST logic series. It features a 4-bit bidirectional counting architecture with positive edge triggering and asynchronous preset capabilities. The device operates in a TTL-compatible environment and supports cascading through dedicated count enable and terminal count outputs. It is housed in a 16-pin Small Outline Package (SOP) with a maximum operating temperature of 70 °C.

Feature Summary

• Supports synchronous bidirectional counting triggered by the rising clock edge
• Enables asynchronous parallel loading for programmable divider applications
• Provides separate Terminal Count Up and Terminal Count Down outputs for cascading

Applications

• Programmable frequency dividers
• Multi-stage counter systems requiring cascading
• Synchronous digital timing control circuits

Procurement Notes

Verify the specific manufacturer source, as Rochester Electronics also lists this part number. Confirm that the package dimensions match the EIAJ TYPE2 SOP-16 specification. Ensure the component meets RoHS compliance requirements if applicable to the design constraints. Check for any obsolescence status or lifecycle changes before finalizing procurement plans.

Selection Notes

Select this component when a high-speed synchronous counter with bidirectional capability is required. The F/FAST series offers faster performance than standard LS logic. Verify that the 5V supply voltage range aligns with the system power rails. Ensure the 16-pin SOP footprint fits the available PCB real estate.

Part Context

This device is part of the 74F191 family of reversible modulo-16 binary counters. It shares functional similarities with the 74F193 but differs in clock input configuration. The 74F191SJ variant specifically denotes the surface-mount SOP-16 package version manufactured or distributed under this designation.

Replacement Considerations

Public confirmed substitute part numbers are not available in the provided documentation.