Texas Instruments ADS8168IRHBR

Overview

ADS8168IRHBR from Texas Instruments is a 16-bit, 8-channel, 1-MSPS successive approximation register (SAR) ADC with integrated reference, REFby2 buffer, and programmable channel sequencer. It supports single-ended and pseudo-differential inputs, delivers 92 dB SNR and ±0.3 LSB INL, and operates across –40°C to +125°C for high-precision sensor data acquisition in medical gas analyzers and industrial mixed-signal modules.

For engineers reviewing the ADS8168IRHBR datasheet, ADS8168IRHBR pinout, ADS8168IRHBR application, or ADS8168IRHBR equivalent, key selection criteria include its 1-MSPS throughput at 16 MHz SCLK, per-channel window comparator with hysteresis, direct sensor interface via MUX breakout, and dual SDO/SEQSTS multifunction pin for real-time channel status reporting.

Technical Context

The ADS8168IRHBR implements a true SAR architecture with internal sampling capacitor array and asynchronous conversion control. Its analog multiplexer supports manual, on-the-fly, auto-sequence, and custom channel sequencing modes, enabling dynamic input reconfiguration without interrupting acquisition flow.

It integrates a 4.096 V low-drift internal reference (±18 ppm/°C), REFby2 output (VREFP/2), and reference buffer with burst-mode capability for external 2.5–5 V references. The enhanced-SPI interface supports both SDR (70 MHz) and DDR (35 MHz) modes with configurable data alignment and ready/alert signaling.

Key Specifications

Pinout & Package

RHB package: 32-pin VQFN, 5 mm × 5 mm, exposed thermal pad connected to GND. Pinout optimized for analog signal integrity with dedicated AINx, REFP/REFM, MUXOUT-P/MUXOUT-M, and isolated digital power (DVDD) and analog power (AVDD) domains.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADS8167IRHBR and ADS8166IRHBR, the ADS8168IRHBR delivers 2× and 4× higher throughput respectively while maintaining identical analog performance, pin compatibility, and software interface-making it the optimal choice for time-critical, multi-sensor acquisition where latency and channel density are primary constraints.

Availability

ADS8168IRHBR is available at Aetrix Electronics and suitable for chemistry analyzers, anesthesia delivery systems, mixed-signal I/O modules, and intra-data-center telemetry requiring stable component supply, long-term lifecycle assurance, and automotive-grade reliability.

Supply support for ADS8168IRHBR 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 leadership in precision data converters and industrial-grade signal chain solutions.

The ADS816x product line was designed specifically for high-accuracy, low-power, multi-channel sensor interfacing in medical diagnostics, industrial automation, and test equipment-emphasizing integrated reference stability, flexible sequencing, and robust digital interfacing.

FAQ

What is the maximum sampling rate supported by the ADS8168IRHBR?

The ADS8168IRHBR supports a maximum throughput of 1 million samples per second (1 MSPS) across all eight channels in auto-sequence mode. This is achieved with a 16 MHz SCLK in standard SPI mode or up to 70 MHz in source-synchronous SDR mode. At full speed, the device consumes 26.5 mW with all analog blocks enabled, and maintains 92 dB SNR and ±0.3 LSB INL over the full –40°C to +125°C range. The ADS8168IRHBR achieves this performance without external clock multiplication or oversampling.

Does the ADS8168IRHBR require an external reference voltage?

No, the ADS8168IRHBR does not require an external reference voltage. It integrates a precision 4.096 V internal reference with ±18 ppm/°C temperature drift and includes a dedicated REFIO pin that functions as either output (default) or input for external 2.5–5 V references. When using the internal reference, only a 1 µF decoupling capacitor on REFIO is required. The ADS8168IRHBR also provides a buffered REFby2 output (2.048 V) for analog input DC biasing, eliminating external level-shifting components.

How does the channel sequencer in the ADS8168IRHBR operate?

The ADS8168IRHBR features a programmable channel sequencer supporting four modes: manual, on-the-fly, auto-sequence, and custom. In auto-sequence mode, it scans all enabled AINx channels continuously with 1 µs cycle time at 1 MSPS. On-the-fly mode allows dynamic reordering of the scan sequence mid-acquisition via register writes-critical for adaptive sensing in diagnostic equipment. Channel enable/disable, sequencing order, and input configuration (single-ended/pseudo-differential) are controlled through dedicated registers (CHEN, CHSEQ, AIN_CFG), accessible via the enhanced-SPI interface.

What is the function of the SDO-1/SEQSTS pin on the ADS8168IRHBR?

The SDO-1/SEQSTS pin on the ADS8168IRHBR is a multifunction terminal. By default, it operates as SEQSTS (sequence status), indicating real-time channel scan progress in auto and custom sequence modes-e.g., high during AIN0 acquisition, low during AIN1, etc. Alternatively, it can be configured as SDO-1 for dual-data-output mode, doubling serial throughput by transmitting even/odd bits in parallel. Configuration is controlled by the DATA_FORMAT register bit DUAL_SDO_EN. This flexibility eliminates the need for external status polling and simplifies firmware synchronization in time-critical applications.

Can the ADS8168IRHBR interface directly with AC-coupled sensors?

Yes, the ADS8168IRHBR supports direct interfacing with AC-coupled sensors via its integrated REFby2 output, which provides a stable 2.048 V DC bias voltage derived from the internal reference. This rail can be connected to the sensor's coupling capacitor to establish the correct common-mode voltage for pseudo-differential or single-ended acquisition. The device's AIN-COM pin further supports common-mode referencing, and its programmable input configuration (via AIN_CFG register) allows seamless adaptation to AC-coupled topologies without external op-amps or bias networks-reducing design complexity and improving signal integrity.