Analog Devices Inc./Maxim Integrated MAX1402CAI+

Overview

The MAX1402CAI+ from Maxim Integrated is a low-power, 18-bit sigma-delta analog-to-digital converter (ADC) with three fully differential or five pseudo-differential input channels, matched 200µA on-chip current sources for sensor excitation, and 16-bit accuracy at up to 480sps output data rate. It operates from a +5V analog supply and +3V/+5V digital supply, and targets precision measurement in loop-powered industrial sensors and portable weighing systems.

For engineers reviewing the MAX1402CAI+ datasheet, MAX1402CAI+ pinout, MAX1402CAI+ application, or MAX1402CAI+ equivalent, key selection criteria include its programmable decimation filter for line-frequency rejection (50Hz/60Hz), ±117% input-referred DC offset compensation, and SPI/QSPI-compatible 3-wire serial interface supporting automatic channel scanning.

Technical Context

The MAX1402CAI+ implements a sigma-delta modulator with digital decimation filtering, where user-selectable decimation factors trade resolution for output data rate-achieving true 16-bit performance at 480sps. Its modulator sampling frequency is configurable for lowest power (250µA operating current) or highest throughput.

It supports dual-supply operation (+5V analog, +3V/+5V digital), features fully differential reference inputs, and integrates two auxiliary calibration channels (CALGAIN±, CALOFF±) for system-level gain and offset correction-enabling high-accuracy measurements without external calibration circuitry.

Key Specifications

Pinout & Package

The MAX1402CAI+ is housed in a 28-pin SSOP (shrink small-outline package) with exposed pad, footprint code A28-2. Pin functions are validated per Maxim's official pin configuration diagram and datasheet Table 1.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar precision sigma-delta ADC applications.

Compared with ADS124S08IPW and AD7793BRUZ, the MAX1402CAI+ uniquely combines on-chip 200µA excitation matching, five pseudo-differential inputs via AIN6, and dual calibration channels-making it optimal for compact, multi-sensor loop-powered designs needing both flexibility and low power.

Availability

The MAX1402CAI+ is available at Aetrix Electronics and suitable for portable industrial instruments, loop-powered transmitters, and pressure transducer applications requiring stable component supply and long-term manufacturability.

Supply support for MAX1402CAI+ 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.

The MAX1402CAI+ belongs to Maxim's high-accuracy, low-power sigma-delta ADC product line, engineered specifically for battery- and loop-powered sensor signal conditioning with integrated excitation and calibration resources.

FAQ

What is the maximum output data rate with guaranteed 16-bit no-missing-codes performance for the MAX1402CAI+?

The MAX1402CAI+ achieves guaranteed 16-bit no-missing-codes performance at an output data rate of up to 480 samples per second (sps). This specification is verified under standard conditions: V+ = +5V, fCLKIN = 2.4576MHz, and TA = TMIN to TMAX. At higher data rates, resolution is reduced via decimation factor adjustment, trading bits for speed.

Does the MAX1402CAI+ include on-chip current sources for sensor excitation, and what are their key specifications?

Yes, the MAX1402CAI+ integrates two matched 200µA transducer excitation current sources (OUT1 and OUT2). These sources exhibit ±1% initial tolerance and 5ppm/°C drift match, with compliance voltage ranging from AGND to (V+ − 1.0V). They are optimized for driving resistive sensors such as RTDs and Wheatstone bridges without external components.

Can the MAX1402CAI+ reject 50Hz and 60Hz line interference, and how is this implemented?

Yes, the MAX1402CAI+ provides 150dB normal-mode rejection at both 50Hz and 60Hz through its programmable digital decimation filter. When configured with a 2.4576MHz master clock and appropriate filter control bits (MF1/MF0 = 0), the filter places precise notches at line frequency and harmonics-eliminating the need for external analog filtering or digital post-processing.

How many analog input channels does the MAX1402CAI+ support, and what configurations are possible?

The MAX1402CAI+ supports three fully differential input channels (e.g., AIN1/AIN2, AIN3/AIN4, AIN5/AIN6) or five pseudo-differential channels using AIN6 as a shared common node. Additionally, the CALGAIN± and CALOFF± pins serve as two extra fully differential calibration inputs, which can be repurposed as signal inputs when calibration is disabled in auto-sequence mode.

What digital interface does the MAX1402CAI+ use, and is it compatible with standard microcontrollers?

The MAX1402CAI+ uses a 3-wire SPI/QSPI-compatible serial interface (SCLK, DIN, DOUT) with active-low CS. It operates in standard mode with SCLK idling high and supports register reads/writes, data acquisition, and status reporting. The interface is fully compatible with common microcontrollers including ARM Cortex-M, PIC, and MSP430 families without protocol translation.