Analog Devices Inc./Maxim Integrated MAX1231ACEG+T

Overview

MAX1231ACEG+T 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 features 16 single-ended or 8 true differential analog input channels, operates from a single +3V supply, and supports unipolar/bipolar modes for industrial data acquisition and system supervision.

For engineers reviewing the MAX1231ACEG+T datasheet, MAX1231ACEG+T pinout, MAX1231ACEG+T application, or MAX1231ACEG+T equivalent, this page delivers verified technical context, real-world design meaning of key specs, package-validated pin functions, and two confirmed alternative parts for multi-channel, low-power, temperature-aware ADC selection in embedded monitoring systems.

Technical Context

The MAX1231ACEG+T employs a fully differential successive-approximation register (SAR) architecture with on-chip track-and-hold, supporting both single-ended and true differential inputs across 16 configurable channels. Its internal oscillator enables autonomous scan mode operation without external timing control.

It integrates a dedicated temperature-sensing path using the same internal reference and conversion core, delivering 1/8°C resolution in two's complement format. The 16-deep FIFO buffers conversion results-including temperature readings-allowing burst acquisition without serial bus contention.

Key Specifications

Pinout & Package

The MAX1231ACEG+T is packaged in a 28-pin 5mm × 5mm TQFN with exposed pad (EP), requiring connection of EP 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+T, ADS8684IPWR offers higher resolution at the cost of increased external component count and no integrated thermal sensing, while AD7949BCPZ-RL7 reduces channel count and omits both FIFO and temperature functionality - making MAX1231ACEG+T uniquely balanced for compact, self-contained, thermally aware data acquisition.

Availability

MAX1231ACEG+T is available at Aetrix Electronics and suitable for industrial process monitoring, patient vital sign acquisition, and environmental data logging requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MAX1231ACEG+T 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 MAX1231ACEG+T belongs to the MAX1227/MAX1229/MAX1231 family of low-power, multichannel SAR ADCs engineered for embedded system supervision where integration of FIFO, temperature sensing, and internal reference reduces board space and design complexity.

FAQ

What is the maximum sampling rate of the MAX1231ACEG+T, and under what conditions is it achieved?

The MAX1231ACEG+T achieves a maximum sampling rate of 300ksps when using an externally supplied clock signal up to 10MHz and operating in clock mode 11 (CKSEL1/CKSEL0 = 11). This mode disables internal averaging and scanning but enables full-speed acquisition. At 300ksps, the device maintains 71dB SINAD and ±1 LSB INL/DNL accuracy across the -40°C to +85°C range. The MAX1231ACEG+T must use an external reference in this mode; the internal reference is not active during externally clocked conversions.

Does the MAX1231ACEG+T support true differential input, and how many differential channel pairs are available?

Yes, the MAX1231ACEG+T supports true differential input with eight independent pairs: AIN0/AIN1, AIN2/AIN3, AIN4/AIN5, AIN6/AIN7, AIN8/AIN9, AIN10/AIN11, AIN12/AIN13, and AIN14/AIN15. Each pair is sampled simultaneously by the internal track-and-hold, rejecting common-mode noise and DC offsets. Configuration is performed via the setup register's DIFFSEL bits and unipolar/bipolar mode registers. Differential mode is only available when the corresponding channel pins are not reassigned as CNVST or REF−.

How does the internal temperature sensor in the MAX1231ACEG+T function, and what is its accuracy?

The MAX1231ACEG+T integrates a factory-calibrated diode-based temperature sensor that shares the ADC core and internal 2.5V reference. It delivers measurements in degrees Celsius with 1/8°C resolution in two's complement format. Accuracy is ±0.7°C at +25°C and ±1.2°C over the full -40°C to +85°C operating range. Temperature readings are stored in the FIFO alongside analog conversions and can be triggered independently or interleaved within scan sequences - all without requiring external components or calibration.

What package type and thermal considerations apply to the MAX1231ACEG+T?

The MAX1231ACEG+T is supplied in a 28-pin 5mm × 5mm TQFN package with exposed pad (EP), denoted by the "+T" suffix and RoHS-compliant "+" marking. The exposed pad must be soldered to a solid GND plane on the PCB for optimal thermal dissipation and noise immunity. Thermal resistance θ_JA is 20.8mW/°C above +70°C, allowing up to 1667mW continuous power dissipation at TA = +70°C. Proper pad layout and via stitching are essential to maintain junction temperature below +150°C under full-load operation.

Can the MAX1231ACEG+T operate with an external reference, and what are the voltage limits?

Yes, the MAX1231ACEG+T supports external differential reference operation. REF+ accepts voltages from 1.0V to VDD + 50mV, while REF− accepts 0V to 500mV. When using an external reference, the internal 2.5V reference is disabled, reducing supply current by ~700µA at 300ksps. External reference mode preserves all ADC performance specifications including ±1 LSB INL/DNL and 71dB SINAD, provided the external source exhibits ≤200µV_RMS noise and adequate PSRR. The MAX1231ACEG+T does not regulate or buffer the external reference - source impedance must be <1kΩ for optimal settling.