Analog Devices Inc./Maxim Integrated MAX1237EUA

Overview

The MAX1237EUA from Maxim Integrated is a low-power, 12-bit, 4-channel analog-to-digital converter (ADC) with integrated track/hold, 2.048V internal reference, I²C-compatible 2-wire serial interface, and operation from 2.7V to 3.6V supply. It delivers 94.4ksps throughput, ±1 LSB INL/DNL accuracy, and auto-shutdown current below 1µA-enabling high-precision sensing in battery-powered portable instrumentation.

For engineers reviewing the MAX1237EUA datasheet, MAX1237EUA pinout, MAX1237EUA application, or MAX1237EUA equivalent, this page provides verified technical context, real-world design implications of its 2-wire interface timing modes (400kHz Fast Mode / 1.7MHz High-Speed Mode), differential/single-ended input configurability, and supply-current vs. throughput behavior at -40°C to +85°C.

Technical Context

The MAX1237EUA employs successive-approximation architecture with fully differential track-and-hold circuitry, supporting software-configurable unipolar/bipolar and single-ended/differential analog inputs across four channels. Its internal 2.048V reference enables full-scale input ranges of 0–2.048V (unipolar SE) or ±1.024V (bipolar diff), while external reference support extends range flexibility from 1V to VDD.

It operates in two I²C timing modes: Fast Mode (400kHz SCL, ≤22.2ksps) and High-Speed Mode (1.7MHz SCL, up to 94.4ksps), requiring explicit master-code handshake for mode transition. Conversion timing is clocked internally (2.8MHz) or externally via SCL, with aperture delay as low as 30ns in HS-mode and 800ns track/hold acquisition time.

Key Specifications

Pinout & Package

The MAX1237EUA is housed in an 8-pin µMAX® package (3mm × 3mm, 0.5mm pitch), optimized for space-constrained portable applications. Pin functions are validated per Maxim's official datasheet Rev 7 (19-2333).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 12-bit, I²C-interfaced, low-power ADC applications.

Compared with ADS7822U and MCP3221-AI/P, the MAX1237EUA uniquely combines 2.048V internal reference, µMAX packaging, and guaranteed -40°C to +85°C performance in a drop-in I²C solution-reducing BOM count and board area for compact, battery-efficient designs.

Availability

The MAX1237EUA is available at Aetrix Electronics and suitable for handheld portable applications, medical instruments, and battery-powered test equipment requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX1237EUA 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 communications applications.

The MAX1236–MAX1239 family was engineered for ultra-low-power, multi-channel data acquisition in space- and energy-constrained systems-emphasizing integrated references, I²C efficiency, and robust performance across temperature extremes.

FAQ

What is the maximum sampling rate supported by the MAX1237EUA?

The MAX1237EUA achieves a maximum sampling rate of 94.4ksps when operating in I²C High-Speed Mode (1.7MHz SCL). This requires the host master to issue the HS-mode entry sequence (0000 1XXX) before initiating conversion reads. In default Fast Mode (400kHz), throughput is limited to 22.2ksps. The MAX1237EUA's internal clock runs at 2.8MHz, ensuring consistent timing regardless of bus speed.

Does the MAX1237EUA require an external reference voltage?

No, the MAX1237EUA includes a factory-trimmed 2.048V internal reference with ±40mV tolerance over temperature, sufficient for most 12-bit applications. However, it also supports external references from 1V to VDD-enabling custom full-scale ranges or improved stability using precision external references like the MAX6126. When using the internal reference, pin 4 (AIN3/REF) must be decoupled with a 0.1µF capacitor to GND.

How does the AutoShutdown™ feature reduce power consumption in the MAX1237EUA?

The MAX1237EUA's AutoShutdown™ automatically powers down analog circuitry-including reference, T/H, and core ADC-between conversions. At low throughput rates (e.g., 1ksps), supply current drops to 6µA; in idle state with no conversions pending, it falls below 1µA. This eliminates the need for firmware-controlled enable/disable sequencing, making the MAX1237EUA ideal for wake-on-event sensor nodes where microcontroller sleep dominates system power budget.

Can the MAX1237EUA perform differential measurements?

Yes, the MAX1237EUA supports fully differential analog inputs across its four channels (e.g., AIN0–AIN1, AIN2–AIN3/REF) when configured via the SGL/DIF bit in the setup byte. In differential mode, it accepts bipolar inputs up to ±1.024V (with internal 2.048V reference) and outputs results in two's complement format. This capability enables accurate measurement of bridge sensors, isolated signals, or noise-prone industrial transducers without external instrumentation amplifiers.

What are the absolute maximum ratings for the analog input pins of the MAX1237EUA?

The MAX1237EUA analog input pins (AIN0–AIN3/REF) tolerate voltages from -0.3V to (VDD + 0.3V), protected by internal clamping diodes. However, for accurate conversion, input signals must remain within the specified operating range: 0 to VREF for unipolar single-ended, or ±VREF/2 for bipolar differential. Exceeding GND – 50mV or VDD + 50mV risks measurement error-even if within absolute max limits-due to forward-biasing protection structures.