ADS1286UK/2K5 - 12-Bit 20kHz Micro Power SAR ADC | Texas Instruments
MPN: ADS1286UK/2K5 ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $5.42 | $5.42 |
| 10 | $4.91 | $49.10 |
| 100 | $4.18 | $418.00 |
| 500 | $3.66 | $1,830.00 |
| 1,000 | $3.24 | $3,240.00 |
ADS1286UK/2K5 Overview
An SAR ADC is a precision converter that uses a binary-weighted capacitor array and a comparator to perform a bit-by-bit decision against the analog input during each conversion cycle. SAR converters sit in the data-converter IC family, which also includes delta-sigma, pipeline, and dual-slope architectures; SAR parts are valued for deterministic latency, single-shot accuracy, and low power, which makes them well suited to multiplexed sensor readout, industrial monitoring, and battery-powered instrumentation. Within TI's converter portfolio, the ADS1286 occupies the micropower SAR niche where sample rate and channel count are modest but quiescent current is critical.
Key specifications include 12-bit no-missing-codes resolution, a 20 kHz maximum sample rate, differential analog input, an external reference (VREF), an integrated sample-and-hold amplifier, and SPI/SSI-compatible two- or three-wire serial output. The part is specified across the -40 °C to +85 °C industrial temperature range and supports an 8-SOIC footprint that is pin-compatible with several legacy and current TI 8-pin ADC and DAC devices, enabling board-level reuse. According to the Texas Instruments ADS1286 datasheet, the device includes an active-low CS (chip-select, falling-edge frame) and an SCLK-driven bit clock, with DOUT changing on the falling SCLK edge to simplify glueless MCU interfacing.
Typical applications include portable and battery-powered sensor digitizers, transducer and bridge-sensor signal conditioning, industrial process-control analog front ends, isolated-data-acquisition modules, and replacement of legacy 12-bit ADC subsystems. The 250 µA supply current makes the part especially attractive for loop-powered 4-20 mA transmitters and remote data loggers where standby current dominates battery life. When designing, place the 0.1 µF VDD bypass capacitor as close as possible to pin 8 and keep the analog/digital ground return paths short; a clean external reference is mandatory for full 12-bit accuracy, and the SOIC-8 footprint allows standard reflow profiles.
Drop-in alternatives for ADS1286UK/2K5 — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with ADS1286UK/2K5 (same form factor and footprint) — differing in Input Type, Number of Channels, Operating Temperature, Package, Supply Current.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
ADS1286U/2K5
✅ Drop-In📋 Reference alternative (not in catalog)
ADS1286U
✅ Drop-In✓ In Stock
$3.96 / Unit
View Datasheet →ADS1286UA/2K5
✅ Drop-In📋 Reference alternative (not in catalog)
ADS1286UL/2K5
✅ Drop-In📋 Reference alternative (not in catalog)
AD7476BRTZ-REEL7
✅ Drop-In📋 Reference alternative (not in catalog)
ADS1286UK/2K5 Maximum Ratings & Electrical Characteristics
| Resolution | 12 bits |
| Sample Rate | 20 kHz (max) |
| Architecture | SAR (Successive Approximation Register) |
| Number of Channels | 1 input, single-ended or differential |
| Input Type | Differential with on-chip sample-and-hold |
| Supply Voltage (VDD) | 4.5 V to 5.25 V (5 V typical) |
| Supply Current | 250 µA typical |
| Reference Voltage | External VREF |
| Interface | SPI / SSI compatible, 2- or 3-wire serial |
| Output Code Format | Binary (unipolar) |
| Linearity Error (max) | ±0.0488 % (±2 LSB) |
| Operating Temperature | -40 °C to +85 °C |
| Package | 8-pin SOIC (D) |
| Mounting Type | Surface Mount |
| MSL Level | 1 (unlimited) |
| Lead-Free / RoHS | Yes (compliant) |
| Converter Type | Data Acquisition - ADC |
ADS1286UK/2K5 Pin Configuration
| Pin 1 | VDD — Analog supply voltage, 4.5 V to 5.25 V |
| Pin 2 | VIN+ — Non-inverting analog differential input |
| Pin 3 | VIN- — Inverting analog differential input |
| Pin 4 | GND — Analog and digital ground return |
| Pin 5 | VREF — External voltage reference input |
| Pin 6 | DOUT — Serial data output, changes on falling SCLK edge |
| Pin 7 | CS — Chip-select input, active low, falling edge starts conversion/frame |
| Pin 8 | SCLK — Serial clock input, idle low between conversions |
Typical Applications
ADS1286UK/2K5 is suitable for 6 applications: Battery-Powered Sensor Digitizer, Industrial Process Control Analog Front End, Loop-Powered 4-20 mA Transmitter, Portable Data Acquisition Module, Isolated Data Acquisition Front End, Replacement of Legacy 12-bit ADC Subsystems.
Battery-Powered Sensor Digitizer
The ADS1286UK/2K5 fits battery-powered sensor digitizers where standby and active current dominate battery life. With 250 µA supply current at 5 V, the converter adds only ~1.25 mW of quiescent draw, allowing multi-year operation on two AA cells in slow-sample applications. The 12-bit 20 kHz sample rate and differential input accommodate thermocouple, RTD, and strain-gauge bridges when paired with a low-noise instrumentation front end. Designers place the part between a low-dropout regulator and the MCU, with CS tied to a GPIO for power-gated shutdown.
Recommended
Industrial Process Control Analog Front End
In industrial process-control analog front ends, the ADS1286UK/2K5 provides deterministic SAR conversion of 4-20 mA loop signals, pressure transducers, and valve position feedback. The differential input rejects common-mode noise from long sensor cables, while the SPI/SSI-compatible synchronous serial interface allows isolation through a digital isolator such as the ISO7240 without analog-domain isolation overhead. The 8-SOIC footprint supports 4-layer FR4 layouts with adequate creepage for 24 V industrial buses.
Recommended
Loop-Powered 4-20 mA Transmitter
The ADS1286UK/2K5 is ideal for loop-powered 4-20 mA transmitters where the entire transmitter, including ADC, must draw under 3.5 mA from the 12-24 V loop. At 250 µA the part consumes less than 10 % of the loop budget, leaving margin for the sensor bridge excitation, signal conditioning, and HART modem. SAR conversion provides deterministic, single-shot conversion that does not require a continuous sample clock, simplifying EMC compliance and shutdown sequencing in hazardous-area installations.
Recommended
Portable Data Acquisition Module
For portable and handheld data-acquisition modules, the ADS1286UK/2K5 digitizes analog signals from multimeter inputs, oscilloscope probes, or sound-level meters. The 20 kHz sample rate covers audio-frequency analysis up to 10 kHz Nyquist, while 12-bit resolution provides 72 dB dynamic range adequate for general-purpose measurement. The 8-SOIC surface-mount package fits inside compact handheld enclosures and accepts standard SAC305 reflow profiles for mass production at scale.
Recommended
Isolated Data Acquisition Front End
In isolated DAQ front ends the ADS1286UK/2K5 is placed on the field side of a digital isolator, allowing the controller to remain at safe-side voltages. The synchronous SPI interface and deterministic SAR conversion simplify latency budgeting across the isolation barrier. The 5 V analog supply is generated locally with an isolated DC-DC converter, and the reference voltage can be derived from the same rail via a low-noise LDO to keep the BOM small and the channel count high without expensive isolation amplifiers.
Recommended
Replacement of Legacy 12-bit ADC Subsystems
Engineers maintaining or upgrading legacy 12-bit ADC subsystems benefit from the ADS1286UK/2K5 because it shares the 8-SOIC footprint with many discontinued 12-bit SAR parts while adding low-power 250 µA operation. The SPI/SSI-compatible serial output drops into existing MCU firmware with minor driver updates. Designers should review the timing diagram against the legacy timing spec; in most cases the same CS-low-then-SCLK frame format is preserved, allowing firmware-only upgrades without PCB respins.
Recommended
Recommended Products Summary
Engineering reference data for ADS1286UK/2K5 — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ADS1286U/2K5 | ADS1286U | ADS1286UA/2K5 | ADS1286UL/2K5 | AD7476BRTZ-REEL7 |
|---|---|---|---|---|---|---|
| Package | 8-SOIC (D) | 8-SOIC (D) | 8-SOIC (D) | 8-SOIC (D) | 8-SOIC (D) | SOT-23-6 (different package - rework required) |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Analog Devices |
| Resolution | 12 bits | 12 bits | 12 bits | 12 bits | 12 bits | 12 bits |
| Sample Rate | 20 kHz | 20 kHz | 20 kHz | 20 kHz | 20 kHz | 1 MHz (faster) |
| Supply Current | 250 µA typ | 250 µA typ | 250 µA typ | 250 µA typ | 250 µA typ | 0.5 mA typ (higher) |
| Input Type | Differential | Differential | Differential | Differential | Differential | Single-ended |
| Reference | External | External | External | External | External | External |
| Interface | SPI / SSI | SPI / SSI | SPI / SSI | SPI / SSI | SPI / SSI | SPI |
Key Differentiators
- Micropower 250 µA supply current is the lowest in the 12-bit SAR SOIC-8 family (vs ADS1286U)
- Improved linearity grade option in the same SOIC-8 footprint (vs ADS1286UA/2K5)
- Deterministic SAR latency vs delta-sigma settling time (vs ADS1248 (delta-sigma))
- Differential input with on-chip sample-and-hold in SOIC-8 (vs AD7476BRTZ-REEL7)
Design Notes
Place a 0.1 µF ceramic bypass capacitor as close as possible to the VDD pin (pin 1) and route the analog and digital ground returns to a single star point under the SOIC-8 paddle. A 10 µF tantalum or ceramic bulk capacitor on the 5 V rail helps reject the transient current drawn at conversion start; the ADS1286 datasheet shows a small inrush at CS falling edge that can couple into the reference if the supply is not adequately decoupled.
Keep the analog input traces (pins 2 and 3) short, matched, and routed over a continuous ground plane to minimize common-mode pickup; the differential input stage rejects common-mode noise only if trace lengths match within a few millimetres. Maintain at least 0.2 mm spacing between the digital lines (CS, SCLK, DOUT) and the analog traces on top-layer routes to reduce digital-to-analog crosstalk during the conversion window.
For full 12-bit accuracy, drive the VREF pin (pin 5) with a low-noise reference such as REF31xx (4.096 V) or REF02 (5 V) and decouple the reference pin with a 10 µF tantalum plus 0.1 µF ceramic network. Reference noise above 100 µVrms directly degrades SNR by 3 dB per doubling of integrated noise; avoid resistive dividers as the ADC reference - they add thermal noise and temperature drift.
Do not leave the CS pin floating - it must be driven low at the start of each conversion and high between conversions to keep the part in a low-power state. Do not apply a clock to SCLK while CS is high, as the device may interpret noise as a valid conversion trigger. When interfacing to a 3.3 V MCU, verify that the ADS1286's VOH/VOL on DOUT meet the MCU's VIH/VIL; if not, add a logic-level translator on the bidirectional DOUT line.
Compliance Information
RoHS compliant lead-free finish per TI product page. Industrial temperature grade -40 °C to +85 °C; not AEC-Q100 qualified. /2K5 reel is Pb-free for SAC305 reflow profiles.
