Texas Instruments SCANSTA476TSD

Overview

SCANSTA476TSD from Texas Instruments is an IEEE 1149.1-compliant analog voltage monitor IC with eight selectable single-ended analog inputs (A0–A7), 12-bit successive-approximation ADC core, ±2 mV typical measurement accuracy at full VDD, and operation from +2.7V to +5.5V supply. It serves as a JTAG-accessible system health sensor in server power rails and telecom board-level monitoring.

For engineers reviewing the SCANSTA476TSD datasheet, SCANSTA476TSD pinout, SCANSTA476TSD application, or SCANSTA476TSD equivalent, this device enables real-time analog voltage sampling without external microcontroller GPIO-leveraging existing JTAG infrastructure for debug, production test, and field service diagnostics across industrial, medical, and datacom platforms.

Technical Context

The SCANSTA476TSD integrates a 12-bit SAR ADC with internal reference scaling tied to VREF (≤VDD), supporting 0V to VREF input range per channel. Its digital interface is fully compliant with IEEE 1149.1 TAP controller state machine, using TDI/TDO/TCK/TMS/TRST pins for instruction and data shifts.

JTAG instruction op-codes 40h–47h select analog channels A0–A7; data shifts return 12-bit straight-binary samples. Conversion throughput reaches 1 MSPS at 20 MHz TCK, with <1 µs power-up recovery requiring one dummy conversion before valid results.

Key Specifications

Pinout & Package

SCANSTA476TSD uses a 16-pin WSON (NHQ) package with 0.5 mm pitch, 5 mm × 5 mm body, and exposed DAP (Die Attach Pad) on the bottom surface serving as primary GND connection. Thermal performance requires ≥4 vias connecting DAP to PCB ground plane.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar analog voltage monitoring applications.

Compared with ADS7953IRHBT and INA226AIDGST, the SCANSTA476TSD uniquely delivers eight-channel analog monitoring through standardized JTAG-enabling zero-GPIO, zero-firmware-addition integration into existing test and debug workflows while maintaining ±2 mV accuracy and industrial temperature operation.

Availability

SCANSTA476TSD is available at Aetrix Electronics and suitable for server power integrity validation, telecom line card diagnostics, medical imaging subsystem monitoring, and industrial PLC rail supervision requiring stable component supply across extended product lifecycles.

Supply support for SCANSTA476TSD 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 company specializing in analog, embedded processing, and connectivity technologies, with over 90 years of innovation in industrial, automotive, and communications markets.

The SCANSTA476TSD belongs to TI's IEEE 1149.1 analog monitor product line-designed specifically to extend JTAG infrastructure into analog domain for system-level health monitoring, debug, and production test without adding interface complexity.

FAQ

What is the maximum analog input voltage allowed on SCANSTA476TSD channels?

The SCANSTA476TSD analog inputs A0–A7 accept voltages from 0V to VREF, where VREF must be ≤VDD. Since VDD operates from +2.7V to +5.5V, the absolute maximum analog input is +5.5V-but only if VREF is set to that value. For accurate measurement, VIN must remain strictly below VREF; exceeding it causes saturation and invalid readings. The device does not support rail-to-rail input beyond VREF.

Does SCANSTA476TSD require external clocking or can it operate solely from JTAG TCK?

SCANSTA476TSD operates entirely from the JTAG TCK signal-no external clock source is needed. Its internal ADC timing and sampling control are synchronized to TCK edges, supporting up to 20 MHz TCK frequency. At 20 MHz, the device achieves 1 MSPS throughput. No crystal, oscillator, or auxiliary timing circuitry is required for basic operation.

How is ground connection implemented on the SCANSTA476TSD WSON package?

SCANSTA476TSD uses an exposed Die Attach Pad (DAP) on the underside of its WSON package as the primary GND connection-not a perimeter pin. This DAP must be soldered directly to the PCB ground plane using at least four thermal vias. Pins 1 and 3 are VDD; there is no GND pin on the periphery. Improper DAP grounding degrades noise immunity and thermal performance.

Can SCANSTA476TSD measure negative voltages or differential signals?

No. SCANSTA476TSD supports only single-ended, positive-only analog inputs ranging from 0V to VREF. It has no provision for negative voltage measurement, differential input pairs, or bipolar operation. All eight channels (A0–A7) are referenced to common GND and require externally biased signals above 0V. Differential or AC-coupled signals require external conditioning circuitry.

What JTAG instruction op-codes are used to select analog channels on SCANSTA476TSD?

SCANSTA476TSD uses JTAG instruction register op-codes 40h through 47h (hex) to select analog inputs A0 through A7 respectively. Each op-code loads the corresponding channel into the ADC multiplexer. After loading the instruction, a data register (DR) shift retrieves the 12-bit conversion result. The TAP controller must transition through Capture-DR, Shift-DR, and Update-DR states per standard IEEE 1149.1 protocol.