Texas Instruments ADS8694IDBTR

Overview

ADS8694IDBTR from Texas Instruments is a 4-channel, 18-bit successive approximation register (SAR) analog-to-digital converter with integrated analog front-end, ±20 V input overvoltage protection, 1 MΩ constant resistive input impedance, and 500 kSPS aggregate throughput. It operates from a single 5-V analog supply and supports software-programmable bipolar (±10.24 V, ±5.12 V, ±2.56 V) and unipolar (0–10.24 V, 0–5.12 V) input ranges for industrial data acquisition systems.

For engineers reviewing the ADS8694IDBTR datasheet, ADS8694IDBTR pinout, ADS8694IDBTR application, or ADS8694IDBTR equivalent, key selection criteria include channel-independent gain/offset calibration, daisy-chain SPI interface support, on-chip 4.096-V reference with 6 ppm/°C drift, ALARM output with per-channel thresholds, and TSSOP-38 packaging suitable for high-density PLC analog input modules.

Technical Context

The ADS8694IDBTR integrates per-channel programmable gain amplifiers, 2nd-order anti-aliasing LPFs, and overvoltage protection circuitry before the SAR core, enabling direct connection to field sensors without external signal conditioning. Its multiplexer supports both auto-scan and manual channel selection modes, with independent configuration of input range and alarm thresholds per channel.

Digital interface uses SPI-compatible protocol with CS, SCLK, SDI, SDO, and DAISY pins; REFSEL controls internal/external reference selection; RST/PD enables hardware reset or power-down mode; ALARM provides active-high interrupt signaling. All analog inputs maintain 1 MΩ input impedance across all selected ranges, eliminating gain-dependent loading effects.

Key Specifications

Pinout & Package

TSSOP-38 package (9.7 mm × 4.4 mm), thermally enhanced with multiple AGND/DGND/AVDD/DVDD pins for low-noise analog and digital separation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADS8698IPWR and AD7606C-18BSTZ, the ADS8694IDBTR uniquely combines 4-channel integration, on-chip reference, daisy-chain SPI, and ALARM functionality in a compact TSSOP-38 package-reducing component count by ≥7 parts and eliminating reference buffer design effort.

Availability

ADS8694IDBTR is available at Aetrix Electronics and suitable for power automation, protection relays, and PLC analog input modules requiring stable component supply, long-term industrial lifecycle support, and guaranteed traceability.

Supply support for ADS8694IDBTR 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 ICs.

The ADS869x product line was designed specifically for high-reliability industrial data acquisition, integrating signal conditioning, protection, and conversion in a single chip to simplify sensor interface design in harsh environments.

FAQ

What input voltage ranges does the ADS8694IDBTR support?

The ADS8694IDBTR supports five software-programmable input ranges: ±10.24 V, ±5.12 V, ±2.56 V, 0–10.24 V, and 0–5.12 V. Each of the four analog input channels can be independently configured to any of these ranges via SPI register writes, enabling flexible sensor interfacing without external hardware changes. The ADS8694IDBTR maintains 1 MΩ input impedance across all ranges.

Does the ADS8694IDBTR require an external reference voltage?

No, the ADS8694IDBTR includes an integrated 4.096-V reference with 6 ppm/°C maximum temperature drift and 0.01% initial accuracy. When REFSEL is pulled low, the internal reference is enabled and appears on the REFIO pin. An external reference can be used by pulling REFSEL high and applying 4.046–4.146 V to REFIO, but it is not required for standard operation of the ADS8694IDBTR.

How does the ALARM function work on the ADS8694IDBTR?

The ALARM pin on the ADS8694IDBTR is an active-high, open-drain output that asserts when any enabled channel exceeds its programmable high or low threshold. Thresholds are set per channel via SPI-accessible registers, and ALARM remains asserted until cleared by reading the status register or writing to the ALARM clear bit. This enables event-driven wake-up and fault logging without continuous polling of the ADS8694IDBTR.

Can multiple ADS8694IDBTR devices be connected in daisy-chain mode?

Yes, the ADS8694IDBTR supports daisy-chain configuration using the DAISY pin. In this mode, the SDO of one device connects to the SDI of the next, allowing serial data from multiple ADS8694IDBTR units to be read back through a single host SPI interface. Chip select (CS) must be asserted simultaneously for all devices in the chain, and the total number of clock cycles scales linearly with device count - a key feature confirmed in the ADS8694IDBTR datasheet.

What is the operating temperature range of the ADS8694IDBTR?

The ADS8694IDBTR is rated for industrial operation from –40°C to +125°C ambient temperature. This specification is guaranteed across all electrical parameters including INL (±1.5 LSB), SNR (93.5 dB), and input impedance (1 MΩ ±15%), making it suitable for deployment in enclosures exposed to wide thermal swings, such as outdoor substations or factory-floor control cabinets.