Analog Devices Inc./Maxim Integrated MAX1287EKA+T

Overview

MAX1287EKA+T from Maxim Integrated is a 12-bit, 2-channel single-ended analog-to-digital converter (ADC) operating from a +3V supply in an 8-pin SOT23 package. It delivers 150ksps sampling rate, ±1.0 LSB INL, 70dB SINAD, and 0.5mW power consumption at full speed - enabling high-precision, low-power data acquisition in space-constrained portable systems.

For engineers reviewing the MAX1287EKA+T datasheet, MAX1287EKA+T pinout, MAX1287EKA+T application, or MAX1287EKA+T equivalent, key selection criteria include its true single-supply +3V operation, software-configurable channel selection via CNVST, SPI/QSPI/MICROWIRE compatibility, and guaranteed no-missing-codes performance across –40°C to +85°C.

Technical Context

The MAX1287EKA+T implements a successive-approximation register (SAR) architecture with integrated track-and-hold, supporting two single-ended analog inputs (AIN1, AIN2) referenced to GND. Its conversion is initiated by a rising edge on CNVST, followed by automatic hold and 3.7µs internal conversion using a 4MHz ±10% internal clock.

It features AutoShutdown™ mode (<0.2µA between conversions), fast 1.4µs acquisition time, and a 3-wire serial interface where DOUT outputs MSB-first data on SCLK falling edges - compatible with SPI, QSPI, and MICROWIRE protocols at up to 8MHz clock rate.

Key Specifications

Pinout & Package

Package: 8-pin SOT23 (3.0mm × 1.6mm × 1.1mm), RoHS-compliant, exposed pad not connected (per MAX1287EKA+T ordering info).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 12-bit SAR ADC applications.

Compared with ADS7822IDR and MAX11100ETE+, the MAX1287EKA+T offers the lowest active power (245µA) in the smallest 8-pin SOT23 package, making it optimal for size- and battery-constrained portable instrumentation where external reference sourcing is acceptable.

Availability

MAX1287EKA+T is available at Aetrix Electronics and suitable for portable temperature monitors, flowmeters, and touch screens requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MAX1287EKA+T 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 demanding industrial, medical, and portable applications.

The MAX1286–MAX1289 family was engineered for ultra-low-power, high-resolution data acquisition in battery-operated instruments - emphasizing small footprint, single-supply operation, and SPI-compatible simplicity.

FAQ

What is the maximum sampling rate of the MAX1287EKA+T, and how does it affect power consumption?

The MAX1287EKA+T achieves a maximum sampling rate of 150ksps, drawing 245µA (0.5mW) at +3V. Power scales dynamically: 150µA at 100ksps, 15µA at 10ksps, and only 0.2µA in AutoShutdown™ mode. This enables adaptive power management in portable systems where throughput varies by use case - for example, reducing current during idle periods in a handheld multimeter while preserving full-speed capability for transient capture.

How does the MAX1287EKA+T select between its two analog input channels (AIN1 and AIN2)?

The MAX1287EKA+T uses CNVST timing to select channels: a single high pulse ≥1.4µs selects AIN1; a high–low–high pulse sequence (each ≥30ns) selects AIN2. This eliminates external multiplexers and reduces BOM count. The selection occurs during track mode before conversion begins, ensuring deterministic channel routing without software overhead - critical for synchronized dual-sensor sampling in flowmeter applications.

Does the MAX1287EKA+T require an external reference, and what voltage range is supported?

Yes, the MAX1287EKA+T requires an external reference applied to the REF pin, supporting +1.0V to VDD+50mV (i.e., +1.0V to +3.65V). For standard operation at +3V supply, a +2.5V reference is typical, yielding a 0–2.5V input range. A 0.1µF bypass capacitor is mandatory at REF for noise rejection. This external reference flexibility allows system-level calibration and compatibility with precision voltage references like the MAX6126.

What serial interface protocols does the MAX1287EKA+T support, and what configuration is required?

The MAX1287EKA+T supports SPI, QSPI, and MICROWIRE protocols with CPOL = 0 and CPHA = 0. It outputs 12-bit MSB-first data on DOUT, transitioning on SCLK falling edges. For SPI, two 8-bit reads are needed; for QSPI, one 12-bit read suffices. No mode pins or registers are required - interface behavior is hardwired, simplifying firmware integration on MCUs like PIC16 or ARM Cortex-M0+.

Is the MAX1287EKA+T pin-compatible with other devices in the MAX1286–MAX1289 family?

Yes, all MAX1286–MAX1289 variants share identical 8-pin SOT23 and 8-pin TDFN pinouts, including MAX1287EKA+T. Pin functions (VDD, AIN1, AIN2, GND, REF, CNVST, DOUT, SCLK) are consistent across the family. However, electrical differences exist: MAX1286/MAX1288 operate at +5V and support single-ended inputs only, while MAX1287EKA+T is +3V-specific and shares the same dual-channel single-ended topology as MAX1286EKA-T - enabling drop-in replacement within the +3V subgroup.