Texas Instruments ADS8691IPW

Overview

ADS8691IPW from Texas Instruments is an 18-bit, 1-MSPS successive approximation register (SAR) analog-to-digital converter with integrated analog front-end, programmable bipolar/unipolar input ranges (±12.288 V to ±2.56 V or 0–12.288 V), on-chip 4.096-V low-drift reference, and multiSPI™ interface. It operates from a single 5-V analog supply with 1.65–5-V I/O support and delivers ±0.6 LSB DNL, 92.5 dB SNR, and ±1.75 LSB INL across industrial temperature range (–40°C to +125°C). Used in high-precision data acquisition modules for semiconductor test equipment.

For engineers reviewing the ADS8691IPW datasheet, ADS8691IPW pinout, ADS8691IPW application, or ADS8691IPW equivalent, this page provides verified technical context, package mapping, real-world use-value per application, validated alternatives, and supply-chain readiness - all grounded in TI's SBAS777B datasheet and official TSSOP-16 device documentation.

Technical Context

The ADS8691IPW implements a true single-supply SAR architecture with integrated PGA, second-order LPF, overvoltage protection (±20 V), and software-configurable gain/offset calibration per input range. Its analog input structure maintains ≥1 MΩ resistive impedance regardless of selected range, enabling direct connection to high-impedance sensors without external buffering.

Digital interface flexibility includes standard SPI and multiSPI™ modes (daisy-chain capable), with three clocking options: host-driven (asynchronous), source-synchronous with external clock, or source-synchronous with internal clock (15 ns period). ALARM output supports high/low threshold monitoring independent of conversion cycle timing.

Key Specifications

Pinout & Package

TSSOP-16 package (5.00 mm × 4.40 mm), thermally enhanced for industrial ambient operation up to +125°C; JEDEC MO-153 compliant with exposed pad not present.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADS8681IPW and AD7606C-18BSTZ, the ADS8691IPW uniquely combines 18-bit precision, single 5-V supply operation, software-programmable wide input ranges, and compact TSSOP-16 packaging - making it optimal for new industrial DAQ designs prioritizing integration density and supply simplicity.

Availability

ADS8691IPW is available at Aetrix Electronics and suitable for analog input modules, semiconductor test systems, and LCD panel test equipment requiring stable component supply, extended temperature support, and long-term production continuity.

Supply support for ADS8691IPW 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 and embedded processing technologies, with decades of expertise in precision data converters and industrial-grade signal chain solutions.

The ADS869x family was designed specifically for high-accuracy, single-supply data acquisition in harsh environments - targeting applications where programmability, robustness, and minimal external components are critical design constraints.

FAQ

What is the maximum sampling rate of the ADS8691IPW?

The ADS8691IPW achieves a maximum throughput rate of 1 million samples per second (1 MSPS) with no latency, corresponding to a 1-µs conversion cycle time. This is confirmed in Section 6.6 of the SBAS777B datasheet and applies under recommended operating conditions (AVDD = 5 V, DVDD = 3.3 V, TA = –40°C to +125°C). The ADS8691IPW maintains full 18-bit performance at this rate, unlike the slower ADS8695 (500 kSPS) and ADS8699 (100 kSPS) variants in the same family.

Does the ADS8691IPW require an external reference voltage?

No, the ADS8691IPW does not require an external reference voltage because it integrates a highly stable 4.096-V reference with 4–7 ppm/°C temperature drift and 20-ms turn-on time. The REFIO pin can be configured as an output to drive external circuitry or as an input to accept an external reference - but operation with the internal reference is fully supported and validated across the full temperature range. Using the internal reference reduces BOM count and improves system-level accuracy consistency.

What input voltage ranges does the ADS8691IPW support?

The ADS8691IPW supports eight software-programmable input ranges: five bipolar (±12.288 V, ±10.24 V, ±6.144 V, ±5.12 V, ±2.56 V) and three unipolar (0–12.288 V, 0–10.24 V, 0–6.144 V, 0–5.12 V). Each range is calibrated for gain and offset error during manufacturing, ensuring dc precision without user calibration. Range selection is performed by writing to internal registers via the multiSPI™ interface - no hardware modifications are needed.

How does the ALARM function work on the ADS8691IPW?

The ALARM pin on the ADS8691IPW is a multi-function output that operates as an active-high hardware interrupt triggered when the converted input value exceeds user-defined high or low thresholds. These thresholds are programmed into dedicated registers and compared continuously against conversion results - independent of host processor polling. When triggered, ALARM asserts immediately (within one conversion cycle), enabling fast fault response in safety-critical systems such as motor overcurrent detection or battery overvoltage shutdown.

Is the ADS8691IPW pin-compatible with other devices in the ADS869x family?

Yes, the ADS8691IPW is pin-compatible with the ADS8695IPW and ADS8699IPW - all share the same TSSOP-16 (PW) package, identical pinout, and register map. This allows hardware reuse across speed grades: a single PCB layout can support 1-MSPS (ADS8691IPW), 500-kSPS (ADS8695IPW), or 100-kSPS (ADS8699IPW) variants simply by changing the BOM and firmware configuration. No PCB redesign or layout modification is required when selecting between these members of the ADS869x family.