Texas Instruments ADS5281IRGCT

Overview

ADS5281IRGCT from Texas Instruments is a 12-bit, 8-channel, 50MSPS octal analog-to-digital converter with serialized LVDS outputs, integrated PLL clock buffer, and programmable digital gain (0–12 dB). It operates from 3.3V analog and 1.8V digital supplies, delivers 70dBFS SNR at 10MHz IF, and targets high-density data acquisition in medical imaging and wireless infrastructure.

For engineers reviewing the ADS5281IRGCT datasheet, ADS5281IRGCT pinout, ADS5281IRGCT application, or ADS5281IRGCT equivalent, key selection considerations include its QFN-64 package, 50MSPS sampling rate, internal/external reference flexibility, LVDS bit clock (6× sample rate), and channel power-down capability for dynamic power management.

Technical Context

The ADS5281IRGCT implements a fully differential pipeline ADC architecture with on-chip PLL-based clock conditioning, supporting both single-ended and differential clock inputs with duty-cycle correction. Its serialized DDR LVDS output interface transmits 12-bit data per channel across eight differential pairs at 6× the sample rate (e.g., 300MHz LCLK at 50MSPS).

It features programmable digital gain, selectable internal (2.0V) or external reference, low-frequency noise suppression mode, and 6dB overload recovery in one clock cycle. The device supports straight offset binary or two's complement output format and includes serial register control via SPI-compatible interface (CS/SCLK/SDATA/RESET).

Key Specifications

Pinout & Package

ADS5281IRGCT is housed in a thermally enhanced 64-pin QFN package (9mm × 9mm) with exposed PowerPAD™ for improved thermal performance. Pin count: 64; RoHS-compliant, green (Pb-free, no Sb/Br) finish.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar octal ADC applications.

Compared with ADS5282IRGCT and ADS5271IPFP, the ADS5281IRGCT delivers optimal balance of sampling rate, power efficiency (649.5mW total), and compact QFN-64 packaging-making it ideal for new designs prioritizing density and thermal performance at 50MSPS.

Availability

ADS5281IRGCT is available at Aetrix Electronics and suitable for medical imaging systems, wireless infrastructure base stations, and high-speed test instrumentation requiring stable component supply, long-term lifecycle support, and RoHS-compliant manufacturing.

Supply support for ADS5281IRGCT 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 high-performance data converters for industrial, automotive, and communications markets.

The ADS528x family was designed to address high-channel-count, low-power digitization needs in portable and dense signal acquisition systems-emphasizing serialized LVDS output, flexible reference architecture, and fine-grained power management.

FAQ

What is the maximum sampling rate supported by the ADS5281IRGCT?

The ADS5281IRGCT is specified for a maximum sampling rate of 50MSPS across all eight channels simultaneously. This is confirmed in the official TI datasheet SBAS397I (Rev. June 2012), where the ADS5281 grade is explicitly defined as "12-bit, 50MSPS" - distinct from the ADS5282 (65MSPS). Operation beyond 50MSPS is not guaranteed and may degrade AC performance metrics such as SNR and SFDR.

Does the ADS5281IRGCT support both internal and external voltage references?

Yes, the ADS5281IRGCT supports dual reference modes. When the INT/EXT pin is high, it uses an internal trimmed 2.0V reference (VREFT – VREFB = 2.0V ±50mV). When INT/EXT is low, it accepts external reference voltages applied to REFT (2.4–2.6V) and REFB (0.4–0.6V), drawing up to 3.5mA total loading. This flexibility allows system-level reference sharing or highest accuracy with precision external sources.

What package type and pin count does the ADS5281IRGCT use?

The ADS5281IRGCT uses a 64-pin QFN package (RGC suffix), measuring 9mm × 9mm with an exposed thermal pad (PowerPAD™). This is confirmed in TI's ordering table: ADS5281IRGCT maps to "QFN-64" with marking "AZ5281". It is not pin-compatible with the HTQFP-80 variant (e.g., ADS5281IPFP) due to differing pin count, layout, and thermal pad configuration.

How does the ADS5281IRGCT handle clock inputs and jitter sensitivity?

The ADS5281IRGCT accepts differential (LVDS/LVPECL) or single-ended CMOS clock inputs on CLKP/CLKN pins and includes an on-chip duty-cycle correction (DCC) circuit. Its aperture jitter is specified at 400fs (typical), and aperture delay variation is ±20ps (3σ) across channels. These specs ensure tight timing alignment critical for multi-channel coherent sampling - validated under conditions of AVDD = 3.3V, LVDD = 1.8V, and 50MSPS operation.

Can the ADS5281IRGCT be interfaced directly with Xilinx FPGAs?

Yes, the ADS5281IRGCT's serialized DDR LVDS outputs are explicitly supported for direct interface with Xilinx FPGAs, as documented in Xilinx Application Note XAPP774. The device outputs 12-bit data per channel on eight differential LVDS pairs, synchronized to LCLKP/LCLKN (6× sample rate) and ADCLKP/ADCLKN (1× frame clock), matching common FPGA I/O standards and timing requirements for high-speed data capture.