Analog Devices Inc./Maxim Integrated MAX145AEUA+T

Overview

MAX145AEUA+T from Maxim Integrated is a -40°C to +85°C temperature-grade, 12-bit pseudo-differential successive-approximation ADC with 108ksps sampling rate, SPI/QSPI/MICROWIRE-compatible 3-wire serial interface, and on-chip track-and-hold - used in isolated data acquisition systems requiring low power and compact size.

For engineers reviewing the MAX145AEUA+T datasheet, MAX145AEUA+T pinout, MAX145AEUA+T application, or MAX145AEUA+T equivalent, this page delivers verified electrical parameters, validated µMAX-8 pin mapping, real-world use cases in battery-powered instrumentation, and two confirmed alternative parts with documented functional and packaging differences.

Technical Context

The MAX145AEUA+T implements a SAR architecture with integrated track-and-hold, accepting pseudo-differential inputs (CH+, CH−) where CH− must remain stable within ±0.5LSB relative to GND during conversion. It supports both internal clock mode (2MHz oscillator, 0–5MHz SCLK for readout) and external clock mode (100kHz–2.17MHz), with automatic power-down reducing current to 0.2µA when CS/SHDN = VDD.

Its analog input structure features 9kΩ input resistance and 16pF input capacitance, requiring ≤10Ω reference output impedance and 0.1µF REF bypass. The device achieves 70dB SINAD at 10kHz, 80dB SFDR, and 2.25MHz small-signal bandwidth - enabling undersampling of periodic signals beyond its Nyquist limit.

Key Specifications

Pinout & Package

MAX145AEUA+T is housed in an 8-pin µMAX package (U8-1), measuring 3mm × 3mm × 0.8mm with exposed pad for thermal enhancement and compatible with fine-pitch reflow assembly.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADS7816U and AD7476ARTZ-REEL7, the MAX145AEUA+T uniquely combines pseudo-differential input capability, integrated track-and-hold, and µMAX-8 packaging - making it irreplaceable in space-limited, noise-sensitive, isolated acquisition channels without layout changes.

Availability

MAX145AEUA+T is available at Aetrix Electronics and suitable for portable data logging, isolated data acquisition, and medical instruments requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX145AEUA+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 MAX144/MAX145 family was engineered specifically for low-power, high-accuracy data acquisition in battery-operated and space-constrained systems - emphasizing integration, temperature stability, and serial interface simplicity.

FAQ

What is the maximum sampling rate supported by the MAX145AEUA+T?

The MAX145AEUA+T supports a maximum sampling rate of 108ksps under specified conditions (VDD = +2.7V to +5.25V, fSCLK = 2.17MHz, 16 clocks/conversion). This rate is achievable in external clock mode and corresponds to a 7.4µs conversion time. At lower throughput rates, automatic power-down reduces current draw proportionally - e.g., 100µA at 10ksps and 10µA at 1ksps - without sacrificing resolution or linearity.

Does the MAX145AEUA+T require an external reference voltage?

Yes, the MAX145AEUA+T requires an external reference voltage applied to the REF pin. It accepts 0V to VDD + 50mV, with optimal performance at 2.5V. The device draws up to 250µA during conversion, so the reference source must have ≤10Ω output impedance and be bypassed with a 0.1µF capacitor. Internal reference is not provided - unlike some competing ADCs, MAX145AEUA+T relies entirely on external precision references for full-scale accuracy.

How does the pseudo-differential input of the MAX145AEUA+T differ from true differential operation?

The MAX145AEUA+T uses pseudo-differential input: only CH+ (Pin 2) is actively sampled, while CH− (Pin 3) serves as a stable reference return that must remain within ±0.5LSB of GND. Unlike true differential ADCs, it does not compute (CH+ − CH−) internally. Instead, CH− acts as a quiet analog ground reference - requiring a 0.1µF capacitor to GND to maintain stability. This architecture simplifies front-end design versus fully differential solutions while retaining noise rejection benefits in single-ended signal chains.

What are the power supply requirements for the MAX145AEUA+T?

The MAX145AEUA+T operates from a single +2.7V to +5.25V supply on VDD (Pin 1), with no separate analog or digital rail required. At +3.0V and 108ksps, supply current is 0.9mA; at 1ksps, it drops to 10µA; and in shutdown (CS/SHDN = VDD), it falls to 0.2µA. The device exhibits ±0.15mV power-supply rejection, meaning VDD variations induce minimal offset shift - critical for stable measurements in systems with noisy or unregulated supplies.

Which serial interface standards is the MAX145AEUA+T compatible with?

The MAX145AEUA+T is fully compatible with SPI, QSPI, and MICROWIRE 3-wire serial interfaces. It uses CPOL = 0 and CPHA = 0 timing, with DOUT transitioning on the SCLK falling edge and data latched on the rising edge. The 16-bit output stream includes three leading ones, channel ID, and 12-bit MSB-first data. No level-shifting or protocol translation is needed when interfacing with standard microcontroller SPI peripherals - including PIC16/17 SSP modules and ARM Cortex-M series.