Analog Devices Inc./Maxim Integrated MAX157ACUA+T

Overview

MAX157ACUA+T from Maxim Integrated is a low-power, 10-bit successive-approximation analog-to-digital converter (SAR ADC) with two single-ended input channels, 108ksps sampling rate, ±0.5 LSB INL, and SPI/QSPI/MICROWIRE-compatible 3-wire serial interface - designed for battery-powered instrumentation and portable data logging where space and power are constrained.

For engineers reviewing the MAX157ACUA+T datasheet, MAX157ACUA+T pinout, MAX157ACUA+T application, or MAX157ACUA+T equivalent, this page delivers verified electrical specifications, µMAX-8 package mapping, channel-switching behavior, shutdown current (<0.2µA), and real-world interface timing constraints - all confirmed against Maxim's official 19-1388 Rev 0 datasheet.

Technical Context

The MAX157ACUA+T implements a SAR architecture with integrated track/hold, using an on-chip laser-trimmed oscillator for internal clock mode (±20% tolerance at ~2MHz) or supporting external SCLK up to 2.17MHz. It samples CH0 and CH1 alternately upon CS/SHDN toggling, with channel identification bit embedded in the 16-bit serial output stream.

Its analog front-end features 9kΩ input resistance, 16pF input capacitance, and supports source impedances ≤4kΩ without performance degradation. The device accepts 0V to VREF single-ended inputs, requires an external reference (0–VDD+50mV), and delivers 66dB SINAD at 10kHz with 70dB SFDR.

Key Specifications

Pinout & Package

MAX157ACUA+T is housed in an 8-pin µMAX package (3mm × 3mm, 0.5mm pitch), thermally enhanced with exposed pad, rated for 0°C to +70°C operation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 10-bit serial ADC applications.

Compared with MAX157ACUA+T, MAX144ACUA+ offers higher resolution at lower speed and greater power, while ADS7822U delivers higher throughput and resolution but lacks automatic shutdown and internal clock flexibility - making MAX157ACUA+T optimal for ultra-low-power, dual-channel, intermittently sampled systems.

Availability

MAX157ACUA+T is available at Aetrix Electronics and suitable for battery-powered data loggers, portable medical sensors, industrial process monitors, embedded system supervisors, and isolated data acquisition circuits requiring stable component supply across extended production lifecycles.

Supply support for MAX157ACUA+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) is a U.S.-based semiconductor company specializing in high-performance analog, mixed-signal, and power-management ICs for industrial, automotive, and communications markets.

The MAX157/MAX159 family was designed specifically for low-power, space-constrained data acquisition - emphasizing single-supply operation, integrated T/H, and flexible serial interfacing in miniature packages.

FAQ

What is the operating temperature range for MAX157ACUA+T?

The MAX157ACUA+T is specified for 0°C to +70°C ambient operation, as indicated by the 'C' suffix in the part number and confirmed in the Ordering Information table (Rev 0, p.2). This commercial-grade rating aligns with its target use in portable consumer and industrial instrumentation rather than extended-temperature environments.

Does MAX157ACUA+T support pseudo-differential input mode?

No, MAX157ACUA+T is the MAX157 variant and supports only two single-ended analog inputs (CH0 and CH1), both referenced to GND. Pseudo-differential operation is exclusive to the MAX159 family members (e.g., MAX159ACUA+). The datasheet explicitly distinguishes CH1 functionality: "CH1 (CH−)" is labeled "Analog Input, MAX157: Single-Ended (CH1)" in the Pin Description table (p.7).

What reference voltage is required for MAX157ACUA+T?

MAX157ACUA+T requires an external reference voltage applied to the REF pin, with a recommended value of 2.5V per the Electrical Characteristics tables. The device accepts 0V to (VDD + 50mV), but performance (e.g., noise floor, INL) degrades below 2.5V. A 0.1µF ceramic capacitor must be placed close to the REF pin for stability, and the reference source must supply ≥250µA DC load current with ≤10Ω output impedance.

How does channel selection work on MAX157ACUA+T?

MAX157ACUA+T alternates between CH0 and CH1 automatically: after power-on reset, it converts CH0 first; subsequent conversions toggle between CH0 and CH1 on each CS/SHDN falling edge. To convert the same channel repeatedly, assert and de-assert CS/SHDN twice per conversion cycle. The channel ID bit (CHID) is embedded in the serial output stream - '0' for CH0, '1' for CH1 - enabling firmware to identify source without external control lines.

Can MAX157ACUA+T operate with an internal clock, and what is its accuracy?

Yes, MAX157ACUA+T supports internal clock mode when SCLK is held high during the CS/SHDN falling edge. Its on-chip laser-trimmed oscillator runs at approximately 2MHz with ±20% tolerance (per Detailed Description, p.8), enabling conversion without an external clock source. This mode is mandatory for SCLK frequencies <100kHz or >2.17MHz and simplifies timing in microcontroller systems where precise clock generation is unavailable.