Texas Instruments SCANSTA112VSX

Overview

SCANSTA112VSX from Texas Instruments is a 7-port IEEE 1149.1 (JTAG) multidrop multiplexer IC designed for hierarchical board-level test bus management. It supports up to 249 unique slot addresses, provides bidirectional backplane and LSP0 ports, enables transparent mode buffering, and operates from 3.0–3.6 V. It is used in high-density system-level JTAG test infrastructure for FPGA/ASIC programming and boundary-scan isolation.

For engineers reviewing the SCANSTA112VSX datasheet, SCANSTA112VSX pinout, SCANSTA112VSX application, or SCANSTA112VSX equivalent, key selection criteria include its 7 configurable local scan ports, 32-bit TCK counter for self-test, 16-bit LFSR signature compactor, TRST-ignoring capability on backplane port, and support for live insertion/withdrawal in modular backplane systems.

Technical Context

The SCANSTA112VSX implements dual-level IEEE 1149.1 addressing: Level 1 selects individual or multicast groups of devices on a shared backplane via 8-slot address inputs; Level 2 configures internal port routing (single, serial group, or bypass) using Mode Register 0. Its TAP controller is fully compliant with IEEE Std. 1149.1 and supports both ScanBridge and Stitcher operational modes.

It features bidirectional master/slave logic enabling either backplane port (B0/B1) to act as master while the other becomes LSP00, and includes OE-controlled tri-state capability on all local scan ports to allow alternate test masters to seize control. The device integrates a 32-bit TCK counter and 16-bit LFSR for on-chip self-test during concurrent scan operations.

Key Specifications

Pinout & Package

SCANSTA112VSX is packaged in a 100-pin NFBGA (NZD) with 0.8 mm pitch, RoHS-compliant SNAGCU ball finish, and MSL Level-4 rating (260°C peak reflow, 72-hour floor life). The package supports high-density PCB layouts and thermal performance suitable for industrial backplane environments.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar IEEE 1149.1 multidrop multiplexer applications.

Compared with SCANSTA111SM and SCANPSC110SM, SCANSTA112VSX delivers expanded scalability (7 ports), deterministic self-test capability (32-bit TCK counter + LFSR), and enhanced system flexibility (bidirectional ports, TRST-ignoring, pass-through I/O), making it the only option qualified for modern industrial backplane test architectures requiring live insertion and hierarchical partitioning.

Availability

SCANSTA112VSX is available at Aetrix Electronics and suitable for industrial backplane test infrastructure, modular telecom chassis design, and high-reliability FPGA/ASIC programming systems requiring stable component supply and long-term lifecycle support.

Supply support for SCANSTA112VSX includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and connectivity technologies, with decades of leadership in JTAG and boundary-scan innovation.

SCANSTA112VSX belongs to TI's IEEE 1149.1 test infrastructure product line, engineered specifically for scalable, addressable, and hierarchical JTAG bus expansion in industrial and telecom backplane systems.

FAQ

What is the primary function of the SCANSTA112VSX in a JTAG test system?

The SCANSTA112VSX functions as a 7-port IEEE 1149.1 multidrop multiplexer that enables hierarchical, addressable access to multiple local JTAG chains from a single backplane test bus. It allows selective activation of individual scan ports, supports broadcast/multicast addressing, and facilitates system-level test and programming without physical reconfiguration. Its role is central to scalable boundary-scan infrastructure in complex electronic systems.

Does SCANSTA112VSX support live insertion and removal in powered backplane systems?

Yes, SCANSTA112VSX explicitly supports live insertion/withdrawal per its datasheet specifications. This capability is enabled by robust I/O protection, defined power-up states, and controlled tri-state behavior on all ports during power transitions. It ensures safe hot-plug operation in modular chassis where boards may be added or removed without powering down the entire system.

How does the bidirectional backplane port architecture work in SCANSTA112VSX?

SCANSTA112VSX features two bidirectional backplane ports (B0 and B1), controlled by the MPselB1/B0 pin. When one is selected as master, the other becomes LSP00 - allowing either port to assume master control of the scan chain network while the unselected port serves as an auxiliary local port. This architecture enables redundant test access and flexible topology design without hardware changes.

What is the purpose of Transparent Mode in SCANSTA112VSX, and how is it activated?

Transparent Mode removes SCANSTA112VSX's internal registers and pad-bits from the JTAG scan chain, allowing legacy ATPG vectors-generated for direct device connection-to be reused without modification. It is activated via the TRANS pin at power-up or through a specific instruction in ScanBridge/Stitcher mode, ensuring backward compatibility and reducing vector generation overhead.

Can SCANSTA112VSX be used to route non-JTAG signals such as flash programming pulses?

Yes, SCANSTA112VSX includes general-purpose pass-through I/O (A0/A1/Y0/Y1 pins) that can deliver write pulses to flash memory or monitor device status signals. These pins operate independently of JTAG protocol timing and are available on both backplane and local ports (LSP0/LSP1), extending its utility beyond pure boundary-scan to system-level configuration and diagnostics.