Analog Devices Inc./Maxim Integrated MAX157ACPA+

Overview

MAX157ACPA+ 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 differential nonlinearity, and SPI/QSPI/MICROWIRE-compatible 3-wire serial interface - designed for battery-powered instrumentation and portable data logging systems.

For engineers reviewing the MAX157ACPA+ datasheet, MAX157ACPA+ pinout, MAX157ACPA+ application, or MAX157ACPA+ equivalent, this page delivers verified technical context, real-world design meaning of key specs, validated pin functions, and confirmed alternative options for space-constrained, low-power signal acquisition.

Technical Context

The MAX157ACPA+ implements a SAR architecture with integrated track/hold, operating from a single +2.7V to +5.25V supply. It supports internal clock mode (laser-trimmed ~2MHz oscillator) and external clock mode (100kHz–2.17MHz), with automatic power-down (<0.2µA) triggered by CS/SHDN high.

Its analog front-end accepts 0V to VREF single-ended inputs on CH0 and CH1, features 16pF input capacitance, 9kΩ input resistance, and 2.25MHz small-signal bandwidth - enabling accurate digitization of transients while maintaining <50ps aperture jitter and 66dB SINAD at 10kHz.

Key Specifications

Pinout & Package

MAX157ACPA+ is housed in an 8-pin µMAX package (3mm × 3mm, 0.8mm height), thermally enhanced with exposed paddle, 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 SAR ADC applications.

Compared with MAX144ACPA+, MAX157ACPA+ trades 2 bits of resolution for 8% higher throughput and 40% lower active current; versus ADS7822U, it offers integrated T/H and wider supply range but at lower speed and different package geometry.

Availability

MAX157ACPA+ is available at Aetrix Electronics and suitable for battery-powered data loggers, portable medical sensors, industrial process monitors, test equipment front-ends, and isolated data acquisition systems requiring stable component supply and long-term lifecycle support.

Supply support for MAX157ACPA+ 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 MAX157ACPA+ belongs to Maxim's low-power SAR ADC product line, engineered specifically for space- and energy-constrained signal acquisition where integration, accuracy, and ease of interface are critical.

FAQ

What is the maximum sampling rate of the MAX157ACPA+?

The MAX157ACPA+ achieves a maximum sampling rate of 108ksps under specified conditions (VDD = +3.6V, fSCLK = 2.17MHz, 16 clocks/conversion). This rate is sustained with full 10-bit accuracy and meets DNL and INL specifications across the 0°C to +70°C temperature range. At lower throughput rates, the device automatically reduces current consumption - e.g., 100µA at 10ksps - making MAX157ACPA+ adaptable to variable-speed acquisition tasks.

Does the MAX157ACPA+ include an internal track/hold circuit?

Yes, the MAX157ACPA+ integrates a track/hold (T/H) circuit optimized for its SAR architecture. The T/H enters tracking mode on the falling edge of CS/SHDN and acquires the analog input within 2.5µs (tACQ). This eliminates the need for external T/H components, reducing bill-of-materials cost and PCB area - a key advantage in compact systems like handheld medical instruments where MAX157ACPA+ is commonly deployed.

What reference voltage options are supported by the MAX157ACPA+?

The MAX157ACPA+ requires an external reference voltage applied to the REF pin, supporting 0V to (VDD + 50mV) with a minimum input resistance of 18kΩ. For optimal performance, a stable 2.5V reference with ≤10Ω output impedance and a 0.1µF ceramic bypass capacitor is recommended. The MAX157ACPA+ does not support internal reference operation - all conversions scale linearly relative to the externally supplied VREF.

How does the MAX157ACPA+ handle channel selection between CH0 and CH1?

The MAX157ACPA+ alternates between CH0 and CH1 automatically after each conversion: CH0 is sampled first upon power-up or CS/SHDN assertion, followed by CH1, then back to CH0. Channel selection is controlled solely by toggling CS/SHDN - no register writes or command sequences are needed. If only one channel is used, CH0 and CH1 may be tied together, though the output data retains the channel ID bit, ensuring MAX157ACPA+ maintains deterministic behavior in all configurations.

Is the MAX157ACPA+ compatible with standard microcontroller SPI peripherals?

Yes, the MAX157ACPA+ is fully compatible with standard SPI, QSPI, and MICROWIRE interfaces. It operates with CPOL = 0 and CPHA = 0, and DOUT transitions on the falling edge of SCLK while data is sampled on the rising edge. The 16-bit serial frame (three leading ones, CHID, 10-bit data, two sub-LSBs) can be read in two 8-bit transfers - confirming seamless integration with common MCUs such as PIC16, ARM Cortex-M0+, and MSP430 without custom firmware overhead for MAX157ACPA+.