Analog Devices Inc./Maxim Integrated MAX1089EKA

Overview

MAX1089EKA from Maxim Integrated is a 10-bit, true-differential analog-to-digital converter (ADC) operating from a single +3V supply in an 8-pin SOT23 package. It delivers 150ksps sampling rate, ±1.0 LSB INL, 61dB SINAD, and auto-shutdown current of 0.2µA - optimized for low-power portable data acquisition where differential signal integrity and space-constrained PCB layout are critical.

For engineers reviewing the MAX1089EKA datasheet, MAX1089EKA pinout, MAX1089EKA application, or MAX1089EKA equivalent, this page provides verified technical context, real-world timing behavior, differential input configuration details, SPI/QSPI/MICROWIRE interface compatibility, and validated alternative options for battery-powered sensor interfaces.

Technical Context

The MAX1089EKA implements a successive-approximation register (SAR) architecture with an integrated true-differential track-and-hold (T/H), supporting unipolar (0 to VREF) and bipolar (±VREF/2) conversion modes selected via CNVST pulse sequencing. Its internal 4MHz oscillator enables fixed 3.7µs conversion time without external clock dependency.

It features a 3-wire serial interface compatible with SPI, QSPI, and MICROWIRE protocols (CPOL=0, CPHA=0), outputs 12-bit frames (10-bit result + 2 sub-bits) MSB-first on DOUT, and enters AutoShutdown (<0.2µA) between conversions when CNVST remains low - eliminating need for software-controlled power gating.

Key Specifications

Pinout & Package

MAX1089EKA is housed in an 8-pin SOT23 package (top mark: AAEX), with exposed-pad variants available separately (ETA+T). The SOT23 footprint supports high-density layouts while maintaining thermal performance for continuous 150ksps operation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar true-differential 10-bit ADC applications.

Compared with ADS7822U and AD7476ARTZ-REEL7, MAX1089EKA uniquely combines true-differential input, software-selectable unipolar/bipolar range, AutoShutdown, and 8-pin SOT23 packaging - making it the only option meeting all four requirements simultaneously in space- and power-constrained designs.

Availability

MAX1089EKA is available at Aetrix Electronics and suitable for portable temperature monitors, flowmeters, and touch screen controllers requiring stable component supply, RoHS-compliant packaging, and guaranteed long-term availability through Maxim's product longevity program.

Supply support for MAX1089EKA 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

Maxim Integrated (now part of Analog Devices) designs precision analog, mixed-signal, and power-management ICs for industrial, medical, and communications applications - emphasizing integration, reliability, and low-power innovation.

MAX1089EKA belongs to the MAX1086–MAX1089 family of micropower, serial-output ADCs engineered specifically for battery-operated data acquisition systems demanding high accuracy, minimal board area, and robust noise immunity.

FAQ

What is the maximum sampling rate of the MAX1089EKA, and under what conditions is it guaranteed?

The MAX1089EKA achieves a guaranteed maximum sampling rate of 150ksps when operated with VDD = +2.7V to +3.6V, fSCLK ≤ 8MHz, and proper 0.1µF REF bypassing. This rate corresponds to a fixed 3.7µs conversion time driven by its internal 4MHz oscillator - independent of external clock stability or µP timing margins.

How does the MAX1089EKA implement true-differential input, and what is its common-mode rejection capability?

The MAX1089EKA uses an integrated differential track-and-hold with matched input capacitance on AIN+ and AIN− pins, enabling direct sampling of voltage differences. Its input structure provides ≥100dB common-mode rejection at DC and maintains >60dB rejection up to 100kHz - verified by measured channel-to-channel offset matching of ±0.1 LSB and CMR of ±0.1mV.

Can the MAX1089EKA operate with an external reference voltage, and what is the acceptable range?

Yes, the MAX1089EKA requires an external reference applied to the REF pin. The valid range is +1.0V to VDD + 50mV - supporting standard references like +2.5V (for 3V operation) or +4.096V (for 5V variants). A 0.1µF ceramic capacitor must be placed directly between REF and GND to minimize noise-induced gain error.

What interface protocols does the MAX1089EKA support, and how is timing synchronized?

The MAX1089EKA supports SPI, QSPI, and MICROWIRE protocols with CPOL = 0 and CPHA = 0. Data is clocked out MSB-first on DOUT's falling edge of SCLK, and latched by the host on SCLK's rising edge. A full 12-bit frame (10 data + 2 sub-bits) is always required - confirmed in Figures 5a/5b and Table 1 of the official datasheet.

How does AutoShutdown work on the MAX1089EKA, and what is its impact on system power budget?

AutoShutdown activates automatically when CNVST remains low between conversions, reducing supply current to 0.2µA. At 1ksps, average current drops to 1.5µA; at 10ksps, it rises to 13µA - enabling multi-year battery life in intermittent-sensing applications. No software command or register write is needed; behavior is hardware-defined and fully specified in Electrical Characteristics tables.