Analog Devices Inc./Maxim Integrated MAX1228ACEP+T

Overview

The MAX1228ACEP+T from Maxim Integrated is a 12-bit, 300ksps serial analog-to-digital converter with integrated temperature sensor (±1.2°C error over -40°C to +85°C), on-chip 16-entry FIFO, internal 4.096V reference, and SPI/QSPI/MICROWIRE-compatible 3-wire interface. It supports 12 single-ended or 6 true differential input channels in unipolar/bipolar modes and operates from a single +5V supply consuming 2.3mA at full speed - used in industrial data-acquisition systems requiring high channel density and embedded thermal monitoring.

For engineers reviewing the MAX1228ACEP+T datasheet, MAX1228ACEP+T pinout, MAX1228ACEP+T application, or MAX1228ACEP+T equivalent, this page delivers verified electrical specs, QSOP-20 package mapping, real-world use cases in patient monitoring and system supervision, and two validated alternative ADCs with documented functional and layout differences.

Technical Context

The MAX1228ACEP+T implements a fully differential successive-approximation register (SAR) architecture with integrated track-and-hold, supporting both single-ended (0–VREF) and true differential (±VREF/2) acquisition. Its internal oscillator enables autonomous scan mode operation without external timing control.

It features configurable clock modes (CKSEL[1:0]) for conversion triggering - including CNVST-gated internal timing (mode 01), serial-command-triggered (mode 10), and externally clocked high-speed acquisition (mode 11). The device uses two's complement format for bipolar and temperature results, binary for unipolar outputs.

Key Specifications

Pinout & Package

The MAX1228ACEP+T is packaged in a 20-pin QSOP (Quad Small Outline Package) with 0.65mm lead pitch and exposed pad not present - distinct from the TQFN variants of MAX1230. Pin 1 is AIN0; pin 20 is EOC. All power and reference pins require local 0.1µF bypassing.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADS7953IRHBT and AD7490BRUZ, the MAX1228ACEP+T uniquely integrates temperature sensing and a precision 4.096V reference in a proven QSOP package - reducing component count and calibration effort in embedded monitoring systems where thermal awareness and unipolar/bipolar flexibility are essential.

Availability

The MAX1228ACEP+T is available at Aetrix Electronics and suitable for industrial process monitoring, patient vital sign acquisition, and environmental data logging requiring stable component supply across extended temperature ranges (-40°C to +85°C).

Supply support for MAX1228ACEP+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 MAX1226/MAX1228/MAX1230 product line targets high-channel-count, low-power data-acquisition systems needing integrated thermal monitoring and flexible input configuration - optimized for space- and cost-sensitive embedded measurement nodes.

FAQ

What is the maximum sampling rate achievable with the MAX1228ACEP+T?

The MAX1228ACEP+T achieves a maximum sampling rate of 300ksps only in externally clocked mode (CKSEL1, CKSEL0 = 11) with SCLK ≤ 4.8MHz. In internally clocked modes (00, 01, 10), the maximum rate is limited by the ±10% tolerance of the internal 4.4MHz oscillator and associated timing overhead - typically ~270ksps in practice. The MAX1228ACEP+T datasheet specifies 300ksps as the guaranteed maximum under defined conditions.

Does the MAX1228ACEP+T support true differential input measurements?

Yes, the MAX1228ACEP+T supports true differential input measurements across six configurable pairs: AIN0/AIN1, AIN2/AIN3, AIN4/AIN5, AIN6/AIN7, AIN8/AIN9, and AIN10/AIN11. Each pair is sampled simultaneously by the internal track-and-hold circuit, rejecting common-mode noise and DC offset. Configuration is done via the DIFFSEL bits in the setup register, and bipolar mode yields two's complement output.

How is the internal temperature sensor of the MAX1228ACEP+T calibrated and what accuracy can be expected?

The MAX1228ACEP+T internal temperature sensor is factory-trimmed and specified for ±1.2°C accuracy over the full -40°C to +85°C operating range, with ±0.7°C typical error at +25°C. It outputs a 12-bit two's complement code representing temperature in 1/8°C increments. No user calibration is required - the sensor uses the internal 4.096V reference exclusively, ensuring consistent performance independent of external reference choice.

Can the MAX1228ACEP+T operate with an external reference, and how does that affect its functionality?

Yes, the MAX1228ACEP+T supports external differential reference inputs via REF+ (pin 15) and REF- (pin 7, shared with AIN6). When using an external reference, the internal 4.096V reference is disabled, and temperature measurements remain functional since they always use the internal reference. External reference operation maintains all other specifications except reference-related parameters like gain error and PSRR, which now depend on the external source stability.

What package type and lead finish does the MAX1228ACEP+T use, and is it RoHS-compliant?

The MAX1228ACEP+T uses a 20-pin QSOP package with standard gull-wing leads and a lead(Pb)-free, RoHS-compliant finish indicated by the "+T" suffix. It has a body size of 7.2mm × 4.4mm and 0.65mm lead pitch. Unlike the MAX1230 TQFN variants, this part has no exposed thermal pad. The "E" in ACEP denotes the -40°C to +85°C extended temperature grade.