Analog Devices Inc./Maxim Integrated MAX1279BETC+

Overview

MAX1279BETC+ from Maxim Integrated is a 12-bit, true-differential, serial-output analog-to-digital converter (ADC) with internal 2.048V reference, operating at up to 1.5Msps on a single +2.7V to +3.6V supply. It features bipolar input range (±1.024V), 68.5dB SINAD at 525kHz, ±1.5 LSB INL, and 1µA max full power-down current - enabling high-precision data acquisition in space-constrained industrial motor control systems.

For engineers reviewing the MAX1279BETC+ datasheet, MAX1279BETC+ pinout, MAX1279BETC+ application, or MAX1279BETC+ equivalent, this page delivers verified technical context, real-world design meaning for each specification, validated pin functions, confirmed alternative parts with documented functional and application differences, and supply-chain support tailored for embedded industrial and communications hardware development.

Technical Context

The MAX1279BETC+ employs a successive-approximation register (SAR) architecture with an internal true-differential track-and-hold (T/H), supporting bipolar input operation (–VREF/2 to +VREF/2). Its SPI/QSPI/MICROWIRE-compatible 3-wire serial interface uses CNVST to initiate conversion on its falling edge and SCLK to clock out 12-bit two's complement data with three leading zeros - requiring exactly 16 SCLK cycles per conversion.

It integrates a trimmed 2.048V internal reference that remains active in normal and partial power-down modes but disables in full power-down mode, requiring ≥2ms recovery before valid conversion. The separate VL supply (1.8V to VDD) enables direct interfacing with low-voltage digital logic while maintaining analog performance integrity.

Key Specifications

Pinout & Package

The MAX1279BETC+ is housed in a 12-pin 3mm × 3mm TQFN package with exposed paddle (EP), rated for –40°C to +85°C operation. Thermal pad must be soldered to PCB ground plane for optimal thermal performance and EMI suppression.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 12-bit SAR ADC applications.

Compared with ADS8860IDRCT and AD7476AARMZ, the MAX1279BETC+ uniquely combines bipolar input, integrated reference, and dual-supply flexibility in a 3×3mm TQFN - making it the only drop-in solution for space-constrained, low-power, true-differential industrial ADC needs without sacrificing 1.5Msps speed or 12-bit linearity.

Availability

MAX1279BETC+ is available at Aetrix Electronics and suitable for industrial motor control, portable instrumentation, and communications baseband sampling requiring stable component supply, extended temperature operation (–40°C to +85°C), and long-term production continuity.

Supply support for MAX1279BETC+ 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, automotive, and communications markets.

The MAX1277/MAX1279 product line targets high-speed, low-power data acquisition in thermally constrained and noise-prone environments - emphasizing true-differential input integrity, internal reference stability, and seamless digital interface compatibility.

FAQ

What is the input voltage range of the MAX1279BETC+?

The MAX1279BETC+ has a true-differential bipolar input range of –VREF/2 to +VREF/2, which equals –1.024V to +1.024V using its internal 2.048V reference. Absolute input voltage on AIN+ and AIN– must remain between 0V and VDD (2.7V to 3.6V) to avoid damage. This range enables direct connection to differential sensors like current shunts without external level-shifting circuitry - a key advantage over unipolar ADCs such as the MAX1277BETC+.

Does the MAX1279BETC+ require an external reference?

No, the MAX1279BETC+ includes a factory-trimmed 2.048V internal reference accessible at the REF pin. It is active in normal and partial power-down modes, and disabled only in full power-down mode (requiring ≥2ms settling upon exit). The reference provides ±10mV initial accuracy and ±50ppm/°C temperature coefficient - eliminating the need for external references in most applications. Using the internal reference simplifies layout and reduces BOM cost versus alternatives like the AD7476AARMZ, which lacks any on-chip reference.

How does the MAX1279BETC+ enter full power-down mode?

The MAX1279BETC+ enters full power-down mode by executing the partial power-down sequence twice: pull CNVST high after the 3rd but before the 14th SCLK rising edge, wait ≥14 SCLK cycles, then repeat the same CNVST timing. This reduces VDD/VL supply current to ≤1µA max. Full power-down disables the internal reference, so allow ≥2ms for reference stabilization before the next conversion. This two-step entry differs from simpler ADCs and ensures reliable low-leakage state activation - critical for battery-powered portable instruments using the MAX1279BETC+.

What digital interfaces is the MAX1279BETC+ compatible with?

The MAX1279BETC+ supports SPI, QSPI, and MICROWIRE protocols via its 3-wire serial interface (SCLK, CNVST, DOUT). It operates in all four SPI modes (CPOL/CPHA combinations) and requires no mode configuration - unlike fixed-mode ADCs. QSPI mode allows minimum 16-clock-cycle transfers, while SPI/MICROWIRE require two 8-bit reads. This universal compatibility enables direct connection to TI C54x DSPs, ARM Cortex-M MCUs, and Xilinx FPGAs without protocol translation - a feature not found in lower-cost alternatives like the AD7476AARMZ.

What is the significance of the VL pin on the MAX1279BETC+?

The VL pin on the MAX1279BETC+ supplies power to the digital I/O circuitry independently from the analog VDD rail, accepting +1.8V to VDD. This allows direct interfacing with 1.8V logic families (e.g., modern FPGAs or low-voltage MCUs) without level shifters, preserving signal integrity and reducing board area. VL also sets VIH/VIL thresholds and powers the DOUT driver - ensuring robust timing margins even when VDD is at 3.6V and logic is at 1.8V. This dual-supply flexibility is absent in monolithic-supply ADCs such as the ADS8860IDRCT, which mandates external level translation.