Analog Devices Inc./Maxim Integrated MAX1272CUA+

Overview

The MAX1272CUA+ from Maxim Integrated is a fault-protected, software-programmable 12-bit analog-to-digital converter (ADC) with ±12V analog input tolerance, single 5V supply operation, and SPI/QSPI/MICROWIRE-compatible 3-wire serial interface. It supports four input ranges (±10V, ±5V, 0–10V, 0–5V), delivers 87ksps throughput, and integrates a 4.096V internal reference - enabling direct interfacing with industrial 4–20mA sensors in compact data-acquisition systems.

For engineers reviewing the MAX1272CUA+ datasheet, MAX1272CUA+ pinout, MAX1272CUA+ application, or MAX1272CUA+ equivalent, key selection criteria include its ±12V fault protection on AIN, guaranteed no-missing-codes performance, 12-bit resolution with ±1 LSB INL, low-power power-down modes (as low as 1 µA), and compatibility with microcontrollers using standard SPI timing (CPOL=0, CPHA=0).

Technical Context

The MAX1272CUA+ employs successive approximation register (SAR) architecture with integrated track/hold, supporting 16-clock conversions at up to 1.4MHz SCLK for 87ksps throughput. Its analog front-end uses a resistor-divider network with programmable polarity (bipolar/unipolar) and range (RNG/BIP bits), requiring <4Ω source impedance to maintain accuracy.

Fault protection operates independently of VDD status, limiting input current to <2mA during ±12V overvoltage events. Power management includes four software-selectable modes - delayed/immediate standby and full power-down - with interface retention and conversion-result availability during all modes.

Key Specifications

Pinout & Package

The MAX1272CUA+ is housed in an 8-pin µMAX® package (3mm × 3mm, 0.5mm pitch), RoHS-compliant and lead-free.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADS7816U and AD7490BRUZ, the MAX1272CUA+ uniquely combines fault protection, integrated reference, and µMAX packaging - reducing BOM count and PCB area in rugged, space-constrained industrial designs.

Availability

The MAX1272CUA+ is available at Aetrix Electronics and suitable for industrial process monitoring, robotics control systems, and portable medical instrumentation requiring stable component supply across extended temperature ranges (-40°C to +85°C).

Supply support for MAX1272CUA+ 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 applications.

The MAX1272CUA+ belongs to Maxim's fault-protected multirange ADC product line, engineered specifically for reliable data acquisition in electrically noisy, high-voltage industrial environments where sensor interface robustness is critical.

FAQ

What input voltage ranges does the MAX1272CUA+ support, and how are they selected?

The MAX1272CUA+ supports four software-selectable input ranges: ±10V, ±5V, 0–10V, and 0–5V. Selection is performed by setting the RNG and BIP bits in the 8-bit control byte sent via its SPI-compatible serial interface. This eliminates external hardware reconfiguration and allows dynamic range adaptation in firmware - essential for multi-sensor systems. The MAX1272CUA+'s internal resistor-divider network scales the input accordingly, with specified accuracy maintained across all ranges.

Does the MAX1272CUA+ require external protection circuitry when interfacing with industrial 4–20mA sensors?

No, the MAX1272CUA+ does not require external protection circuitry for standard 4–20mA sensor interfacing. Its ±12V fault-protected analog input handles common industrial transients and wiring faults directly. When used with a precision shunt resistor (e.g., 250Ω for 1–5V drop), the MAX1272CUA+ digitizes the loop current without additional TVS diodes or clamping networks - simplifying design and improving reliability in harsh environments.

What is the maximum sampling rate of the MAX1272CUA+, and what clock frequency is required?

The MAX1272CUA+ achieves a maximum throughput rate of 87ksps, requiring a serial clock (SCLK) frequency of 1.4MHz. Each conversion uses 16 clock cycles (4 for acquisition, 12 for conversion), and continuous operation demands sustained SCLK with CS held low. At lower rates (e.g., 1ksps), supply current drops to 0.2mA, making the MAX1272CUA+ suitable for low-duty-cycle sensing applications where power efficiency is critical.

Can the MAX1272CUA+ operate with an external reference, and what are the voltage limits?

Yes, the MAX1272CUA+ supports external reference operation with voltages from 2.40V to 4.18V applied to the REF pin. The internal reference buffer must be disabled via the REF bit in the control byte. External references below 4.096V reduce effective resolution due to increased noise-to-LSB ratio; the MAX1272CUA+'s specified performance (e.g., ±1 LSB INL) assumes use of its internal 4.096V reference or a matched external source.

How does the power-down functionality work in the MAX1272CUA+, and what are the lowest current states?

The MAX1272CUA+ offers four software-programmable power-down modes: delayed/immediate standby and delayed/immediate full power-down. In immediate full power-down mode, supply current drops to 1µA while retaining interface responsiveness - allowing wake-up via the next control byte. Standby mode draws 0.2mA at 1ksps and keeps the reference buffer active, eliminating startup delay. These modes are controlled exclusively through the PD, MODE1, and MODE0 bits in the MAX1272CUA+'s serial control word.