Texas Instruments ADS8509IBDB

Overview

ADS8509IBDB from Texas Instruments is a 16-bit, 250-kSPS successive approximation register (SAR) analog-to-digital converter with integrated sample-and-hold, internal 2.5-V reference, serial SPI-compatible interface, and SSOP-28 package. It supports ±10 V, 0 V to 5 V, and other configurable input ranges, delivers ±2 LSB max INL and ±1 LSB max DNL, and operates from a single +5-V supply - enabling high-precision data acquisition in industrial control and instrumentation systems.

For engineers reviewing the ADS8509IBDB datasheet, ADS8509IBDB pinout, ADS8509IBDB application, or ADS8509IBDB equivalent, key selection considerations include its 250-kSPS throughput, internal/external reference flexibility, daisy-chain-capable serial output, power-down mode (70 mW typ at full rate), and industrial −40°C to +85°C temperature rating.

Technical Context

The ADS8509IBDB implements a capacitor-based SAR architecture with on-chip CDAC, comparator, and clock generator. Its analog front-end includes three differential-input-capable channels (R1IN/R2IN/R3IN), programmable input range selection via external resistors, and precision reference buffering via the CAP pin (2.2-μF tantalum).

Digital interface operation is configurable via EXT/INT and SB/BTC pins: internal or external DATACLK synchronization, straight binary or two's complement output format, and TAG-enabled daisy-chaining for multi-channel systems. BUSY and SYNC signals provide deterministic timing coordination with DSPs or microcontrollers.

Key Specifications

Pinout & Package

ADS8509IBDB is housed in a 28-pin SSOP (DB) package with 0.65-mm lead pitch, 10.2 mm × 5.3 mm body, and exposed thermal pad (not electrically connected). Pin 1 marked by dot; pin numbering follows standard SSOP top-view convention.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 16-bit SAR ADC applications.

Compared with ADS8509IBDB, ADS8515IBDBR removes internal reference dependency at the cost of added external components, while AD7606BSTZ trades single-channel optimization for multi-channel parallelism - making ADS8509IBDB optimal for space-constrained, reference-integrated 16-bit single-channel systems.

Availability

ADS8509IBDB is available at Aetrix Electronics and suitable for industrial process control, medical instrumentation, and portable data acquisition systems requiring stable component supply, long-lifecycle support, and guaranteed traceable sourcing.

Supply support for ADS8509IBDB 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-reliability silicon solutions for industrial, automotive, and communications markets.

The ADS8509IBDB belongs to TI's precision data acquisition portfolio, designed specifically for high-accuracy, low-power, single-supply 16-bit SAR ADC applications in harsh industrial environments.

FAQ

What input voltage ranges does the ADS8509IBDB support?

The ADS8509IBDB supports ±10 V, ±5 V, ±3.33 V, 0–4 V, 0–5 V, and 0–10 V input ranges. Range selection is achieved using external precision resistors per TI's Figure 29 and Figure 30. The device's internal 2.5-V reference and resistor network configuration enable accurate scaling without additional op-amp circuitry. All ranges maintain ±2 LSB INL and ±1 LSB DNL performance across −40°C to +85°C.

How does the ADS8509IBDB handle reference voltage sourcing?

The ADS8509IBDB can operate with either its internal 2.5-V reference (2.48–2.52 V, ±8 ppm/°C drift) or an external 2.3–2.7-V source applied to the REF pin. When using the internal reference, the CAP pin must be bypassed with a 2.2-μF tantalum capacitor to AGND2. External reference mode disables the internal source and improves drift to ±2 ppm/°C - critical for high-stability metrology applications. Both modes retain full 16-bit linearity.

Can the ADS8509IBDB be used in daisy-chain configurations?

Yes, the ADS8509IBDB supports daisy-chaining via its TAG input and DATA output. In external clock mode (EXT/INT = high), the DATA pin of one ADS8509IBDB connects to the TAG pin of the next, allowing serial data from multiple converters to be shifted onto a single bus. This eliminates the need for separate SPI chip selects and simplifies multi-channel synchronization - especially useful in modular DAQ systems and motor phase current sensing.

What is the purpose of the PWRD pin on the ADS8509IBDB?

The PWRD pin on the ADS8509IBDB is an active-high power-down control that reduces supply current to 50 mW while preserving the last valid conversion result in the output shift register. This enables low-duty-cycle sampling in battery-powered instruments or thermal-constrained enclosures. Conversion resumes immediately upon pulling PWRD low, with acquisition time (1.8 ms) and conversion time (2.2 ms) fully specified over temperature - ensuring predictable wake-up latency.

Does the ADS8509IBDB require external clocking for serial data transfer?

No - the ADS8509IBDB supports both internal and external clocking for serial data transfer. When EXT/INT is low, DATACLK becomes an output generating 16 precise pulses per conversion, eliminating dependency on host-controlled clocks. When EXT/INT is high, DATACLK accepts an external clock (0.1–26 MHz), enabling tight synchronization with DSP frame timing or FPGA logic. Internal clock mode simplifies interface design; external mode maximizes system-level timing control.