Analog Devices Inc./Maxim Integrated MAX1139KEEE+

Overview

MAX1139KEEE+ from Maxim Integrated is a low-power, 10-bit, 12-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 supports fully differential or single-ended inputs-ideal for battery-powered medical instruments and solar-powered remote monitoring systems.

For engineers reviewing the MAX1139KEEE+ datasheet, MAX1139KEEE+ pinout, MAX1139KEEE+ application, or MAX1139KEEE+ equivalent, key selection criteria include its 12-channel multiplexed architecture, software-configurable unipolar/bipolar mode, AutoShutdown™ current reduction to <1µA, and QSOP-16 package compatibility with space-constrained portable instrumentation designs.

Technical Context

The MAX1139KEEE+ employs successive-approximation ADC architecture with a fully differential track-and-hold stage and switched-capacitor DAC. Its internal 2.048V reference enables precise 10-bit conversion across the full-scale range of 0 to VREF (unipolar) or ±VREF/2 (bipolar differential), with input bandwidth up to 5MHz.

It operates in two I²C modes: Fast Mode (400kHz) and High-Speed Mode (1.7MHz), requiring explicit HS-mode master code (00001XXX) initialization. Channel scanning is managed via an internal FIFO, and acquisition timing is tightly coupled to SCL clock edges-track mode initiates on address acknowledge, hold mode on second clock edge during read.

Key Specifications

Pinout & Package

MAX1139KEEE+ is housed in a 16-pin QSOP package (5.3mm × 10.2mm, 0.635mm pitch), suitable for automated assembly and compact PCB layouts in portable equipment.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX1138EEE+, MAX1139KEEE+ offers lower supply voltage operation and tighter power budgeting for portable use; compared with ADS7822U, it trades 2-bit resolution for integrated reference, I²C simplicity, and channel count-making it optimal for resource-constrained, multi-sensor edge nodes.

Availability

MAX1139KEEE+ is available at Aetrix Electronics and suitable for medical instrumentation, battery-powered test equipment, and solar-powered remote monitoring systems requiring stable component supply across extended temperature ranges (-40°C to +85°C).

Supply support for MAX1139KEEE+ 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 specifically for ultra-low-power, multichannel data acquisition in portable and energy-constrained systems-emphasizing integration of reference, T/H, and I²C interface to minimize external components.

FAQ

What is the maximum sampling rate supported by the MAX1139KEEE+?

The MAX1139KEEE+ achieves a maximum throughput rate of 94.4ksps when operating in I²C High-Speed Mode (1.7MHz SCL). This requires explicit initialization using the HS-mode master code (00001XXX) followed by a repeated START condition. In Fast Mode (400kHz), the maximum rate drops to 22.2ksps. The MAX1139KEEE+ internal clock runs at 2.8MHz, and conversion time is fixed at 10.6µs per sample in external clock mode.

Does the MAX1139KEEE+ require an external reference voltage?

No, the MAX1139KEEE+ includes a factory-trimmed 2.048V internal reference with ±2% tolerance over temperature and supply. It can also accept an external reference from 1V to VDD, but doing so disables the internal reference. When using the internal reference, the AIN3/REF and AIN11/REF pins may be configured as analog inputs or reference outputs-enabling daisy-chained reference distribution in multi-ADC systems.

How does the AutoShutdown™ feature reduce power consumption in the MAX1139KEEE+?

AutoShutdown™ automatically powers down the MAX1139KEEE+ analog core-including reference, T/H, and ADC-between conversions. At low throughput rates (e.g., 1ksps), supply current falls to 6µA; below 100sps, it drops further to <1µA. This eliminates the need for host MCU-controlled enable/disable sequencing, making the MAX1139KEEE+ ideal for event-triggered or timer-wake applications like environmental logging.

Can the MAX1139KEEE+ perform differential measurements across all 12 channels?

No-the MAX1139KEEE+ supports up to six fully differential input pairs (e.g., AIN0–AIN1, AIN2–AIN3, etc.) or twelve single-ended inputs. Differential mode is selected via the SGL/DIF bit in the Configuration Register, and the CS[3:0] bits determine which pair is sampled. Bipolar operation (±VREF/2 range) is only available in differential mode and controlled by the BIP/UNI bit in the Setup Register.

What is the absolute input voltage range allowed on the analog inputs of the MAX1139KEEE+?

The MAX1139KEEE+ analog inputs (AIN0–AIN11) tolerate voltages from (GND − 0.3V) to (VDD + 0.3V) due to internal ESD protection diodes. However, for accurate conversion, input signals must remain within GND to VDD-exceeding these limits by more than 50mV causes nonlinearity or saturation. For bipolar differential operation, the valid common-mode range is GND to VDD, with differential swing limited to ±VREF/2.