Texas Instruments ADS825E/1K

Overview

ADS825E/1K from Texas Instruments is a 10-bit, 40MSPS pipelined analog-to-digital converter (ADC) designed for high-fidelity signal acquisition in demanding imaging and instrumentation systems. It delivers 60dB SNR, 72dBFS SFDR at 1MHz, and ±0.5LSB DNL with single +5V supply operation and +3V/+5V logic I/O compatibility - enabling direct interfacing with FPGA or microcontroller digital buses in medical ultrasound front-ends.

For engineers reviewing the ADS825E/1K datasheet, ADS825E/1K pinout, ADS825E/1K application, or ADS825E/1K equivalent, key selection considerations include its SSOP-28 package, programmable 1Vp-p/2Vp-p input range via RSEL pin, internal/external reference flexibility, differential or single-ended analog input support, and power-down mode reducing consumption to 20mW.

Technical Context

The ADS825E/1K employs a 9-stage pipelined CMOS architecture with on-chip digital error correction logic, ensuring no missing codes and excellent differential linearity across –40°C to +85°C. Its track-and-hold supports both single-ended and fully differential inputs, with common-mode voltage output (CM pin) and internal 3.5V/1.5V reference buffers.

Timing is synchronized to the rising edge of the convert clock (CLK), with 5-clock-cycle data latency and aperture jitter of 1.2ps rms. The device accepts either internal reference (2Vp-p default) or external references (REFT/REFB pins), enabling precise gain/offset matching in multichannel systems.

Key Specifications

Pinout & Package

ADS825E/1K is housed in a 28-pin SSOP (Shrink Small Outline Package) with 0.65mm pitch, optimized for compact high-speed PCB layouts and compatible with standard reflow profiles.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-speed 10-bit ADC applications.

Compared with ADS825E/1K, ADS823E/1K trades SNR for speed, while ADS828E/1K extends both speed and SNR within the same footprint - making ADS828E/1K the preferred upgrade for new designs targeting >50MSPS, whereas ADS825E/1K remains optimal for cost-sensitive 40MSPS applications requiring best-in-class 60dB SNR.

Availability

ADS825E/1K is available at Aetrix Electronics and suitable for medical imaging, test equipment, and video digitizing applications requiring stable component supply, long-term production continuity, and traceable sourcing from authorized channels.

Supply support for ADS825E/1K 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 expertise in precision data converters and high-speed signal chain solutions.

The ADS825E/1K belongs to TI's high-performance pipeline ADC product line, engineered specifically for applications demanding high SNR, low distortion, and flexible analog interface options in medical, test, and video systems.

FAQ

What is the maximum sampling rate supported by the ADS825E/1K?

The ADS825E/1K supports a maximum sampling rate of 40 million samples per second (40MSPS), as specified across its full operating temperature range (–40°C to +85°C). This rate is achievable with proper clock jitter control (<1.2ps rms) and stable analog supply bypassing. At this rate, the ADS825E/1K maintains 60dB SNR and 72dBFS SFDR at 1MHz input frequency, making it suitable for real-time digitization in ultrasound and high-speed test equipment.

Does the ADS825E/1K support both single-ended and differential analog inputs?

Yes, the ADS825E/1K supports both configurations. In single-ended mode, the IN pin is driven with a signal referenced to the CM pin's +2.5V common-mode voltage, while IN is tied to CM. In differential mode, complementary signals are applied to IN and IN with matched impedance and appropriate common-mode bias. The device's internal track-and-hold and error correction logic ensure consistent 10-bit performance in either configuration, with differential operation delivering superior SFDR - up to 74dBFS at 10MHz.

How does the internal/external reference selection work on the ADS825E/1K?

The INT/EXT pin (Pin 18) controls reference source: logic low selects the internal 3.5V/1.5V bandgap-based reference pair, while logic high disables internal buffers and enables external voltages applied to REFT (Pin 22) and REFB (Pin 19). External reference ranges are constrained - REFT must be between (VS – 1.25V) and (REFB + 0.8V), and REFB between 1.25V and (REFT – 0.8V). This flexibility allows multichannel gain matching and full-scale adjustment in systems like CT scanner detector modules.

What logic voltage levels are compatible with the ADS825E/1K digital interface?

The ADS825E/1K supports both +3V and +5V logic levels on its digital interface. The CLK, OE, PD, and RSEL pins accept 3V or 5V CMOS-compatible inputs. Its digital outputs (D0–D9) are driven by the dedicated VDRV pin (Pin 28), which can be set to +3V or +5V to match downstream logic families - enabling direct interfacing with 3.3V FPGAs or 5V microcontrollers without level shifters. Using VDRV = +3V reduces power dissipation and improves noise immunity.

What is the purpose of the CM pin on the ADS825E/1K?

The CM (common-mode) pin (Pin 23) provides a buffered +2.5V DC bias voltage derived from the internal reference ladder. It serves as a stable bias point for driving amplifiers (e.g., OPA680) in single-ended input configurations, eliminating the need for external resistor dividers. Because the CM pin has high output impedance, it must not be loaded beyond ~10µA; for heavier loads, an external buffer amplifier is recommended. This feature simplifies analog front-end design while maintaining optimal ADC performance.