Analog Devices Inc./Maxim Integrated MAX1231ACEG+

Overview

MAX1231ACEG+ from Maxim Integrated is a 12-bit, 300ksps serial analog-to-digital converter with integrated temperature sensor (±0.7°C accuracy), 16-entry FIFO, internal 2.5V reference, and SPI/QSPI/MICROWIRE-compatible 3-wire interface. It supports 16 single-ended or 8 true differential input channels in unipolar/bipolar modes and operates from a single +3V supply. It is used in industrial data-acquisition systems requiring simultaneous voltage and temperature monitoring.

For engineers reviewing the MAX1231ACEG+ datasheet, MAX1231ACEG+ pinout, MAX1231ACEG+ application, or MAX1231ACEG+ equivalent, this page delivers verified technical context, package-validated pin functions, real-world use-value per application, and two confirmed alternative parts with documented functional and application-level differences - all grounded in the official MAX1227/MAX1229/MAX1231 datasheet Rev 7.

Technical Context

The MAX1231ACEG+ employs a fully differential successive-approximation register (SAR) architecture with on-chip track-and-hold, supporting both single-ended and true differential inputs. Its internal oscillator enables autonomous conversion timing in clock modes 00/01/10, while mode 11 accepts external SCLK up to 10MHz for precise 300ksps sampling.

It integrates an analog multiplexer, 16-deep FIFO buffer, internal averaging, AutoShutdown™, and a calibrated silicon temperature sensor referenced to its internal 2.5V reference. All conversions - including temperature measurements - use the internal reference, ensuring consistent offset and gain tracking across temperature.

Key Specifications

Pinout & Package

The MAX1231ACEG+ is packaged in a 28-pin 5mm × 5mm TQFN with exposed pad (EP), rated for –40°C to +85°C operation. The exposed pad must be connected to GND for thermal and electrical performance.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar multichannel, temperature-integrated ADC applications.

Compared with MAX1231ACEG+, ADS8684IPWR offers higher resolution but sacrifices on-chip temperature sensing and FIFO buffering, increasing system-level design effort; AD7928BRUZ provides faster sampling but removes autonomous operation features critical for low-CPU-load embedded monitoring.

Availability

MAX1231ACEG+ is available at Aetrix Electronics and suitable for industrial process monitoring, portable medical devices, environmental data logging, and benchtop test equipment requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX1231ACEG+ 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 MAX1227/MAX1229/MAX1231 product line was engineered for compact, low-power multichannel data acquisition in space-constrained systems requiring integrated temperature awareness and autonomous conversion control - targeting PLCs, portable diagnostics, and distributed sensor networks.

FAQ

What is the maximum sampling rate of the MAX1231ACEG+ and under what conditions?

The MAX1231ACEG+ achieves a maximum sampling rate of 300ksps when using an externally supplied SCLK up to 10MHz in clock mode 11 (CKSEL1/CKSEL0 = 11). This mode disables internal averaging and scanning but enables deterministic, high-speed acquisition. At 300ksps, supply current is 1.75–2.0mA with internal reference enabled, and full-scale bandwidth is 1MHz per the small-signal response specification.

Does the MAX1231ACEG+ require an external reference, or does it have an internal one?

The MAX1231ACEG+ includes a precision internal 2.5V reference (2.48–2.52V, ±30ppm/°C TC) that is always used for temperature measurements and may be selected for analog conversions via the REFSEL bits in the setup register. An external differential reference (REF+/REF−) is optional and supported, but not required - eliminating BOM cost and layout area for reference circuitry in most implementations.

How many analog input channels does the MAX1231ACEG+ support, and how are they configured?

The MAX1231ACEG+ supports 16 single-ended analog inputs (AIN0–AIN15) or 8 true differential input pairs (e.g., AIN0/AIN1, AIN2/AIN3, ..., AIN14/AIN15). Configuration is controlled via the setup and unipolar/bipolar registers: differential mode is enabled per pair, and unipolar/bipolar range selection determines whether the output is binary (0 to VREF) or two's complement (±VREF/2).

What is the function of the FIFO in the MAX1231ACEG+, and how deep is it?

The MAX1231ACEG+ contains a 16-entry first-in/first-out (FIFO) buffer that stores ADC conversion results - up to 16 voltage samples plus one temperature reading. Each entry occupies 2 bytes (MSB-first, with four leading zeros). The FIFO enables burst acquisition without host CPU intervention, allowing the device to autonomously perform multiple conversions while the processor handles other tasks - critical for deterministic real-time data capture.

Can the MAX1231ACEG+ measure temperature, and what is its accuracy?

Yes, the MAX1231ACEG+ integrates a calibrated silicon temperature sensor with ±0.7°C accuracy at +25°C and ±1.2°C over the full –40°C to +85°C operating range. Temperature measurements use the internal 2.5V reference exclusively, are reported in two's complement format at 1/8°C resolution, and appear as the first 2-byte result in the FIFO after a temperature conversion request - enabling reliable board-temperature compensation without external components.