SCANSTA111SM-NS

Specialized Overview

The SCANSTA111SM-NS is an enhanced SCAN Bridge multidrop addressable IEEE 1149.1 (JTAG) port controller manufactured by National Semiconductor. It provides hierarchical and multidrop addressing capabilities, supporting up to 121 unique addresses across seven slot inputs. The device features three configurable local scan ports that can be individually accessed or combined serially. It operates on a 3.0V to 3.6V supply and supports live insertion and withdrawal. Key internal components include a 32-bit TCK counter and a 16-bit LFSR signature compactor for test data management.

Specialized Feature Summary

• Supports true IEEE 1149.1 hierarchical and multidrop addressable capability with extensive address space
• Provides three IEEE 1149.1-compatible configurable local scan ports with flexible bypass and insertion modes
• Enables transparent mode to buffer backplane JTAG pins to local scan ports via single instruction
• Includes general purpose local port pass-through bits useful for FPGA programming write pulses

Specialized Applications

• Multidrop JTAG test bus environments requiring improved test throughput
• Systems needing the ability to remove a board while retaining test access to remaining modules
• Analog bus applications supporting IEEE 1149.4 via LSP active outputs

Specialized Procurement Notes

Verify the specific suffix 'NS' against official National Semiconductor documentation to confirm if it denotes a non-standard or restricted variant distinct from the commercial NOPB version. Ensure the component source is traceable to National Semiconductor or its successor Texas Instruments to guarantee authenticity and compliance with original manufacturing specifications.

Specialized Selection Notes

Select this component when designing systems that require multidrop JTAG connectivity rather than simple serial chains. It is suitable for applications needing simultaneous access to multiple boards or hierarchical test structures. Verify that the system voltage aligns with the 3.0V to 3.6V operating range and that the package type matches the PCB layout requirements.

Specialized Part Context

This part belongs to the SCANSTA family of JTAG bridge controllers originally developed by National Semiconductor. These devices are designed to extend standard IEEE 1149.1 test buses into more complex multidrop architectures. The family includes variants like the SCANSTA112, which offers different port configurations. This specific model focuses on providing robust addressable control for test and debug infrastructure.

Specialized Replacement Considerations

Public confirmed substitute part numbers are not available in the provided reference material. Users should consult official Texas Instruments or National Semiconductor cross-reference guides for verified equivalents, as generic industry substitutes may not support the specific multidrop addressing features.