Texas Instruments ADS805E

Overview

ADS805E from Texas Instruments is a 12-bit, 20MHz pipelined analog-to-digital converter (ADC) with high dynamic range, designed for precision digitization in IF/baseband signal chains. It delivers 74dB SFDR at 9.8MHz input, 68dB SNR, ±0.25LSB differential linearity, and flexible 2Vp-p or 5Vp-p input ranges - enabling high-fidelity capture in studio cameras and test instrumentation.

For engineers reviewing the ADS805E datasheet, ADS805E pinout, ADS805E application, or ADS805E equivalent, key selection considerations include its 6-cycle data latency, over-range flag (OVR), CMOS/TTL-compatible 3-state outputs, internal/external reference support, and SSOP-28 package compatibility with ADS804/ADS803 for design reuse.

Technical Context

The ADS805E employs a high-bandwidth track-and-hold amplifier with <4ps rms aperture jitter and 270MHz analog input bandwidth, minimizing harmonic distortion and preserving SNR up to Nyquist. Its pipelined ADC core integrates digital error correction logic to ensure no missing codes and ±0.25LSB DLE across –40°C to +85°C.

Timing is synchronized to the rising edge of CLK; conversion latency is fixed at 6 clock cycles. The device supports single-ended or differential analog inputs, programmable common-mode voltage (1V–2.5V), and dual-reference operation via REFT/REFB pins - all configurable without external components when using the internal 1V/2.5V bandgap reference.

Key Specifications

Pinout & Package

ADS805E is housed in a 28-pin SSOP (DB) package with exposed pad not electrically connected. Pin assignments are validated per TI SBAS073B datasheet Rev. NOVEMBER 2002.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADS804E and ADS803E, the ADS805E provides the highest sample rate and widest usable input frequency range while maintaining pin compatibility - making it the optimal upgrade path for existing ADS804/ADS803 designs requiring increased throughput without PCB redesign.

Availability

ADS805E is available at Aetrix Electronics and suitable for studio camera modules, IF digitization subsystems, and automated test instrumentation requiring stable component supply across extended production lifecycles.

Supply support for ADS805E 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 with over 50 years of innovation in precision signal chain solutions.

The ADS805E belongs to TI's high-speed pipeline ADC product line, engineered specifically for demanding communications, medical imaging, and instrumentation applications where dynamic range, low distortion, and deterministic latency are critical.

FAQ

What is the maximum input frequency the ADS805E can accurately digitize?

The ADS805E features a 270MHz analog input bandwidth (–3dB) and maintains 68dB SNR and 74dB SFDR up to 9.8MHz input frequency. In undersampling configurations, it successfully captures 41MHz IF signals with 76.3dB SFDR, confirming usability across multiple Nyquist zones. Performance beyond 10MHz depends on clock jitter, layout, and input drive strength - always verify with actual board-level testing.

Does the ADS805E require an external reference, or does it have an internal one?

The ADS805E includes an integrated bandgap reference that outputs either +1V or +2.5V depending on SEL pin configuration - eliminating need for external references in most applications. However, it also supports external reference operation: tie SEL to +VS to disable the internal reference, then drive VREF with a precision external source (e.g., REF1004) for improved DC accuracy in metrology-grade systems.

How does the over-range (OVR) pin function in the ADS805E?

The OVR pin on the ADS805E is a digital output that goes high whenever the analog input exceeds the configured full-scale range - whether above REFT or below REFB. It updates synchronously with the 6-cycle pipeline output, so OVR corresponds to the same sample as the associated D11–D0 data. This enables real-time clipping detection and can trigger automatic gain reduction in the front-end signal chain.

Can the ADS805E interface directly with 3.3V logic systems?

Yes - the ADS805E uses a dedicated VDRV pin (Pin 28) to power its digital output drivers independently from the +5V analog supply. By connecting VDRV to a +3.3V rail, the ADS805E generates TTL/CMOS-compatible output levels (e.g., VOH ≥ 2.4V, VOL ≤ 0.4V at I_OH/I_OL = 0.5mA/1.6mA), enabling seamless interfacing with 3.3V FPGAs or microcontrollers without level shifters.

What is the recommended power supply decoupling for the ADS805E?

TI specifies separate 0.1µF ceramic capacitors placed within 2mm of each +VS (Pins 16, 27) and VDRV (Pin 28), plus a bulk 2.2µF tantalum or 10µF ceramic capacitor near the device. Analog ground (Pins 17, 24, 26) must connect to a solid analog ground plane at the IC; digital and analog grounds join only at this point. Avoid sharing supply traces with noisy digital circuits to preserve 68dB SNR performance.