Analog Devices Inc./Maxim Integrated MAX1137EUA+

Overview

MAX1137EUA+ from Maxim Integrated is a low-power, 10-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 single supply. It delivers 94.4ksps throughput, ±1 LSB INL/DNL, and supports software-configurable unipolar/bipolar and single-ended/differential input modes - ideal for battery-powered medical instruments and portable test equipment.

For engineers reviewing the MAX1137EUA+ datasheet, MAX1137EUA+ pinout, MAX1137EUA+ application, or MAX1137EUA+ equivalent, key selection considerations include its 8-pin µMAX package, I²C fast/high-speed mode support (400kHz/1.7MHz), 670µA max supply current at full rate, AutoShutdown™ enabling sub-1µA standby, and differential analog input architecture with 5MHz small-signal bandwidth.

Technical Context

The MAX1137EUA+ employs successive-approximation ADC architecture with fully differential track-and-hold circuitry and an internal 2.048V reference. Its 2-wire serial interface operates in Fast Mode (400kHz) or High-Speed Mode (1.7MHz), requiring explicit HS-mode entry via master code before achieving 94.4ksps throughput.

It features four analog input channels configurable as either four single-ended or two fully differential inputs, with software-selectable unipolar (0 to VREF) or bipolar (±VREF/2) ranges. Input multiplexer leakage is ±0.01µA, input capacitance is 22pF, and acquisition time is 800ns - all specified over –40°C to +85°C.

Key Specifications

Pinout & Package

The MAX1137EUA+ 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 6, 3/10).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX1136EUA+, the MAX1137EUA+ offers lower supply voltage compatibility and built-in 2.048V reference ideal for 3.3V battery systems, while ADS7822U trades integration for interface flexibility but increases BOM count and layout complexity.

Availability

MAX1137EUA+ is available at Aetrix Electronics and suitable for medical instrumentation, battery-powered test equipment, and solar-powered remote systems requiring stable component supply, RoHS-compliant packaging, and guaranteed operation from –40°C to +85°C.

Supply support for MAX1137EUA+ 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) is a semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for demanding industrial, medical, and communications applications.

The MAX1136–MAX1139 family was designed for ultra-low-power, space-constrained data acquisition in portable and energy-harvesting systems - emphasizing integration (reference, T/H, I²C), supply flexibility, and guaranteed extended-temperature performance.

FAQ

What is the maximum sampling rate achievable with the MAX1137EUA+?

The MAX1137EUA+ achieves a maximum sampling rate of 94.4ksps when operating in I²C High-Speed Mode (1.7MHz clock). This requires the bus master to first issue the HS-mode master code (00001XXX) and then send a repeated START condition followed by the slave address. In Fast Mode (400kHz), the maximum rate drops to 22.2ksps. The MAX1137EUA+ internal clock runs at 2.8MHz, supporting these rates without external timing components.

Does the MAX1137EUA+ require an external reference voltage?

No, the MAX1137EUA+ does not require an external reference voltage because it integrates a precision 2.048V internal reference with 25ppm/°C temperature coefficient. However, it supports optional external reference voltages from 1V to VDD for applications needing custom scaling or improved absolute accuracy. When using the internal reference, the AIN3/REF pin serves as the reference output and must be decoupled with a 0.1µF capacitor to GND.

How many analog input channels does the MAX1137EUA+ support, and how are they configured?

The MAX1137EUA+ supports four analog input channels (AIN0–AIN3/REF), configurable as either four single-ended inputs or two fully differential pairs (e.g., AIN0–AIN1, AIN2–AIN3/REF). Configuration is controlled entirely by software via the SGL/DIF bit in the configuration byte and CS[3:0] channel select bits. No external hardware changes are needed to switch between modes - enabling flexible sensor interfacing in field-upgradable devices.

What power-saving features does the MAX1137EUA+ offer for battery-operated systems?

The MAX1137EUA+ incorporates AutoShutdown™, which automatically powers down the ADC core, reference, and oscillator between conversions - reducing supply current to less than 1µA at low throughput rates. At 1ksps, current drops to 6µA; at 10ksps, it is 60µA. This feature is enabled by default and requires no host intervention, making it ideal for intermittent-sampling applications like environmental monitoring where measurement intervals span seconds or minutes.

Is the MAX1137EUA+ pin-compatible with other devices in the MAX1136–MAX1139 family?

Yes, the MAX1137EUA+ is pin-compatible with the MAX1136EUA+ - both use the identical 8-pin µMAX package and share identical pin assignments (AIN0–AIN3/REF, SCL, SDA, GND, VDD). This allows direct substitution in 3.3V designs when migrating from the 4.096V-reference MAX1136EUA+, provided firmware is updated to account for the different reference voltage scaling in conversion results.