Analog Devices Inc./Maxim Integrated MAX1408CAI+

Overview

MAX1408CAI+ from Maxim Integrated is a low-power, 16-bit sigma-delta multichannel data-acquisition system (DAS) with integrated 10-bit force/sense DACs, internal 1.25V reference, RTC, and SPI-compatible serial interface. It features an 8:1 differential analog input multiplexer, eight auxiliary analog inputs, 30Hz/60Hz continuous conversion rates, and operates from +2.7V to +3.6V with only 1.03mA run-mode current - ideal for portable medical instrumentation and battery-powered industrial sensors.

For engineers reviewing the MAX1408CAI+ datasheet, MAX1408CAI+ pinout, MAX1408CAI+ application, or MAX1408CAI+ equivalent, key selection considerations include its 8-channel analog input capability (vs. 4 in MAX1407), absence of on-chip DACs (distinguishing it from MAX1407/MAX1414), differential input architecture, sleep-mode current of 2.5µA, and 28-pin SSOP package compatibility with space-constrained embedded designs.

Technical Context

The MAX1408CAI+ implements a fully differential 16-bit sigma-delta ADC with programmable gain (1/3, 1, or 2 V/V), unipolar/bipolar mode support, and on-chip offset calibration. Its 8:1 input multiplexer routes signals to the ADC core while maintaining ±1.5 LSB typical integral nonlinearity and 30Hz/60Hz selectable output update rate.

Unlike MAX1407/MAX1414, the MAX1408CAI+ omits force/sense DACs but retains all system-support functions: real-time clock (valid through year 9999), alarm, 2.4576MHz PLL clock output (FOUT), 32.768kHz crystal oscillator, signal-detect comparator (0mV threshold), dual voltage monitors (+1.8V/+2.7V), and wake-up circuitry (WU1/WU2).

Key Specifications

Pinout & Package

MAX1408CAI+ is housed in a 28-pin SSOP (Shrink Small Outline Package) with 0.635mm pitch, footprint-compatible with industry-standard 28-SSOP layouts and suitable for automated SMT assembly.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar multichannel data-acquisition applications.

Compared with MAX1407CAI+, the MAX1408CAI+ removes DACs to reduce cost and power while retaining identical ADC performance and system features - making it optimal for pure acquisition roles. Against ADS1258IPWR, it trades raw resolution and speed for integrated timing, lower quiescent current, and simplified BOM.

Availability

MAX1408CAI+ is available at Aetrix Electronics and suitable for medical instrumentation, industrial process monitoring, and portable test equipment requiring stable component supply, long-lifecycle support, and RoHS-compliant packaging.

Supply support for MAX1408CAI+ 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 MAX1407/MAX1408/MAX1409/MAX1414 family was engineered specifically for low-power, multichannel data acquisition in portable and remote sensing systems - integrating ADC, RTC, reference, and power management into a single 28-pin SSOP device.

FAQ

What is the maximum analog input voltage range for MAX1408CAI+ in unipolar mode with gain = 1?

In unipolar mode with PGA gain = 1, the MAX1408CAI+ supports a differential input voltage range of 0V to VREF (1.25V). With buffered inputs, the absolute input voltage must stay between 0.05V and 1.40V relative to AGND; unbuffered inputs allow 0V to AVDD. This range ensures compatibility with standard sensor outputs and avoids clipping during digitization.

Does MAX1408CAI+ include force/sense DACs like other members of the family?

No, the MAX1408CAI+ does not include force/sense DACs. Per the official feature set table, MAX1408 has zero DACs - unlike MAX1407 and MAX1414 which each integrate two 10-bit force/sense DACs. This omission reduces cost and power while preserving the full 16-bit ADC, RTC, reference, and system support functions in the MAX1408CAI+.

How does the MAX1408CAI+ handle power-supply monitoring and reset generation?

The MAX1408CAI+ integrates two independent voltage monitors: one triggering at +1.8V (bit VM = 1) and another at +2.7V (bit VM = 0), both feeding an open-drain RESET output. When AVDD falls below the selected threshold, RESET asserts low and remains low for a timeout period after AVDD recovers - ensuring reliable microcontroller initialization during brown-out conditions without external supervisor ICs.

Can MAX1408CAI+ operate from a 1.8V supply in all functional modes?

The MAX1408CAI+ supports 1.8V operation only in Sleep mode. In Run, Idle, and Standby modes, the required supply range is +2.7V to +3.6V. This dual-voltage capability enables ultra-low-power retention during standby while maintaining full ADC, RTC, and interface functionality at nominal 3.3V operation - critical for energy-harvesting and battery-gauging applications.

What is the purpose of the FOUT pin on MAX1408CAI+ and what frequency does it deliver?

The FOUT pin on MAX1408CAI+ delivers a precise 2.4576MHz clock signal generated by the internal PLL. This output can directly drive the system microcontroller's external clock input, eliminating the need for a separate crystal oscillator and reducing BOM count. Its cycle-to-cycle jitter is limited to 10ns, supporting timing-critical firmware operations and synchronous peripheral interfacing.