Texas Instruments ADS61B29IRGZT

Overview

ADS61B29IRGZT from Texas Instruments is a 12-bit, 250MSPS analog-to-digital converter with integrated high-impedance analog input buffer, DDR LVDS/parallel CMOS outputs, and programmable fine gain up to 6dB. It operates at 790mW total power dissipation and supports differential input clock amplitudes as low as 400mV_PP, targeting wideband communications infrastructure.

For engineers reviewing the ADS61B29IRGZT datasheet, ADS61B29IRGZT pinout, ADS61B29IRGZT application, or ADS61B29IRGZT equivalent, key selection criteria include its 12-bit resolution at 250MSPS, integrated analog buffer for stable wideband impedance, dual-output interface flexibility, DC offset correction, and industrial temperature range (–40°C to 85°C) operation.

Technical Context

The ADS61B29IRGZT implements a pipelined ADC architecture with on-chip analog buffer enabling constant input impedance across 750MHz analog bandwidth. Its dual-mode digital interface supports either DDR LVDS (12-bit multiplexed pairs D0–D11) or parallel CMOS (12 single-ended outputs D0–D11), selectable via DFS pin.

It features internal reference generation eliminating external reference pins and decoupling capacitors, and includes a DC offset correction loop with hardware/software reset capability via dedicated RESET pin. Power scaling at lower sampling rates maintains performance without manual configuration.

Key Specifications

Pinout & Package

ADS61B29IRGZT is housed in a 48-pin QFN package (RGZ) with 7.0 mm × 7.0 mm footprint and exposed thermal pad connected to DRGND. Pin functions are identical for LVDS and CMOS modes except output pin mapping; MODE pin is unused and NC pins must remain unconnected.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-speed ADC applications.

Compared with ADS6148IRGZT and ADC3662IRSBT, ADS61B29IRGZT uniquely balances 250 MSPS speed, 12-bit accuracy, integrated buffer, and flexible parallel interfaces-making it optimal for wideband feedback loops and legacy FPGA-based digitizers where pin compatibility and analog drive simplicity are critical.

Availability

ADS61B29IRGZT is available at Aetrix Electronics and suitable for wireless infrastructure, radar systems, and test instrumentation requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for ADS61B29IRGZT 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, communications, and automotive markets.

The ADS61Bx9 product line was designed for wideband communications infrastructure demanding high dynamic range, low power, and simplified analog front-end integration-specifically targeting DPD feedback, software-defined radio, and high-definition video digitization.

FAQ

What is the maximum analog input frequency supported by ADS61B29IRGZT at 2 V_PP full-scale?

ADS61B29IRGZT supports a maximum analog input frequency of 500 MHz when operating with a 2 V_PP differential input amplitude. This specification is validated across the full industrial temperature range (–40°C to 85°C) and enables direct sampling of IF signals in multicarrier wireless infrastructure without external anti-alias filtering.

Does ADS61B29IRGZT require external reference components?

No, ADS61B29IRGZT does not require external reference components. It integrates internal references and eliminates traditional reference pins and associated decoupling capacitors. The VCM pin serves as either a common-mode voltage output (2.3 V ±0.1 V) in internal reference mode or as an external reference input, simplifying PCB layout and reducing BOM count.

How does the programmable fine gain feature affect SFDR performance in ADS61B29IRGZT?

In ADS61B29IRGZT, enabling +6 dB fine gain shifts the full-scale input range from 2 V_PP to 1 V_PP, improving SFDR by approximately 3 dB at 170 MHz (e.g., from 74 dBc to 77 dBc) while maintaining SNR within 0.5 dB. This trade-off is implemented digitally and requires no external component changes.

What is the ADC latency of ADS61B29IRGZT in LVDS mode after reset?

The ADS61B29IRGZT exhibits a fixed ADC latency of 18 clock cycles in LVDS mode after hardware reset. This deterministic latency is independent of sampling rate and enables precise timing alignment in closed-loop systems such as digital predistortion, where consistent pipeline delay is critical for algorithm convergence.

Can ADS61B29IRGZT operate with a 1.8-V-only supply configuration?

No, ADS61B29IRGZT requires two separate supplies: AVDD = 3.3 V (±10%) for analog circuitry and DRVDD = 1.8 V (±5%) for digital outputs and interface logic. Using 1.8 V for AVDD would violate absolute maximum ratings and cause functional failure; both rails must be independently regulated per datasheet specifications.