Analog Devices Inc./Maxim Integrated MAX1229ACEP+T

Overview

The MAX1229ACEP+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 configurable 12-channel single-ended or 6-channel true differential input. It operates from a single +3V supply and supports SPI/QSPI/MICROWIRE-compatible 3-wire serial interface up to 10MHz - used in industrial data acquisition and system supervision where compact, low-power multichannel sensing is required.

For engineers reviewing the MAX1229ACEP+T datasheet, MAX1229ACEP+T pinout, MAX1229ACEP+T application, or MAX1229ACEP+T equivalent, this page delivers verified technical context, exact pin functions for the 20-pin QSOP package, real-world use cases in patient monitoring and instrumentation, and two validated alternative parts with documented functional and application-level differences.

Technical Context

The MAX1229ACEP+T employs a fully differential successive-approximation register (SAR) architecture with on-chip track-and-hold, supporting unipolar (0 to VREF) and bipolar (±VREF/2) differential modes plus single-ended operation referenced to GND. Its internal oscillator enables autonomous scan mode without external timing control.

It integrates an internal temperature sensor with 1/8°C resolution and ±0.7°C error at +25°C, always using the internal 2.5V reference for thermal measurements. The 16-deep FIFO buffers conversion results and temperature readings, allowing burst acquisition without serial bus contention.

Key Specifications

Pinout & Package

MAX1229ACEP+T is packaged in a 20-pin QSOP (Quad Small Outline Package) with 0.65mm lead pitch and standard JEDEC MO-137AC footprint. The package is RoHS-compliant and lead-free (+ suffix).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar multichannel ADC applications.

Compared with ADS7822U and AD7490BRUZ, the MAX1229ACEP+T uniquely combines FIFO buffering, internal temperature sensing, and internal reference in a single 20-pin QSOP - reducing component count, PCB area, and firmware complexity for embedded data acquisition systems.

Availability

MAX1229ACEP+T is available at Aetrix Electronics and suitable for industrial process monitoring, portable medical devices, environmental data logging, and benchtop instrumentation requiring stable component supply across extended temperature ranges.

Supply support for MAX1229ACEP+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 demanding industrial, medical, and communications applications.

The MAX1227/MAX1229/MAX1231 product line targets compact, low-power data acquisition systems requiring integrated signal conditioning, multichannel scanning, and on-die thermal awareness - eliminating discrete reference and temperature ICs.

FAQ

What is the operating temperature range for the MAX1229ACEP+T?

The MAX1229ACEP+T is specified for operation from -40°C to +85°C, matching the extended industrial temperature grade. This range applies to all electrical characteristics including INL, DNL, reference voltage stability, and temperature sensor accuracy. The device maintains ±1 LSB linearity and ±1.2°C thermal measurement error across this full span, making it suitable for deployment in harsh environments such as factory floors or outdoor telemetry units.

Does the MAX1229ACEP+T require an external reference voltage?

No, the MAX1229ACEP+T includes a factory-trimmed internal 2.5V reference with ±20mV initial accuracy and ±30ppm/°C temperature coefficient - sufficient for most industrial and medical applications. An external differential reference can be applied via REF+ and REF- pins if higher precision or custom scaling is needed, but doing so disables the internal reference and requires external circuitry. Temperature measurements always use the internal reference regardless of voltage conversion source.

How many analog input channels does the MAX1229ACEP+T support?

The MAX1229ACEP+T supports 12 single-ended analog input channels (AIN0–AIN11) or 6 true differential pairs (AIN0/AIN1 through AIN10/AIN11). Channel configuration is controlled via the setup and conversion registers - enabling dynamic reassignment of pins like CNVST/AIN11 and REF-/AIN10. Unlike the MAX1227 (8 SE / 4 diff) or MAX1231 (16 SE / 8 diff), the MAX1229ACEP+T's 20-pin QSOP package physically implements exactly 12 single-ended inputs.

Can the MAX1229ACEP+T perform simultaneous sampling across multiple channels?

No, the MAX1229ACEP+T uses a single SAR ADC core with multiplexed inputs and does not support true simultaneous sampling. It performs sequential conversions per channel within a scan, with typical acquisition time of 0.6µs and conversion time of 2.7µs per sample. However, its 16-entry FIFO and internal clock modes allow rapid burst acquisition - up to 300ksps aggregate rate - which approximates simultaneous behavior for slowly varying signals like temperature or pressure.

What is the purpose of the EOC pin on the MAX1229ACEP+T?

The EOC (End of Conversion) pin on the MAX1229ACEP+T is an active-low open-drain output that signals completion of the most recent conversion or temperature measurement. In clock modes 00 and 10, EOC pulses low once after the final result is loaded into the FIFO. In clock mode 01, it pulses low after each individual conversion. EOC is always high in externally clocked mode (CKSEL=11). This pin enables interrupt-driven data retrieval without polling DOUT, reducing MCU overhead in real-time systems using the MAX1229ACEP+T.