Analog Devices Inc./Maxim Integrated MAX144AEPA+

Overview

MAX144AEPA+ from Maxim Integrated is a low-power, 12-bit successive-approximation analog-to-digital converter (ADC) with two single-ended input channels, 108ksps sampling rate, ±0.5 LSB INL, and operation from +2.7V to +5.25V supply. It features automatic power-down (0.2µA), 2.5µs wake-up, on-chip track/hold, and SPI/QSPI/MICROWIRE-compatible 3-wire serial interface - used in portable data loggers requiring precision, low quiescent current, and compact DIP packaging.

For engineers reviewing the MAX144AEPA+ datasheet, MAX144AEPA+ pinout, MAX144AEPA+ application, or MAX144AEPA+ equivalent, this page delivers verified electrical specs, thermal range (-40°C to +85°C), DIP-8 package mapping, real-world acquisition timing (tACQ = 7µs), and validated alternatives for battery-powered instrumentation and isolated sensing systems.

Technical Context

The MAX144AEPA+ implements a SAR architecture with integrated track-and-hold, supporting single-ended dual-channel conversion where CH0 and CH1 alternate automatically after power-on reset. Channel selection is controlled via CS/SHDN toggling, and the internal T/H acquires input signals within 7µs using a 16pF hold capacitor and 9kΩ input resistance.

It operates in two clock modes: internal (laser-trimmed ~2MHz oscillator, SCLK high at CS/SHDN fall) or external (SCLK low at CS/SHDN fall, fSCLK = 100kHz–2.17MHz). In external mode, sampling occurs on the second SCLK falling edge, and conversion completes in 7.4µs with 16 clocks per cycle.

Key Specifications

Pinout & Package

MAX144AEPA+ is housed in an 8-pin plastic DIP (dual in-line package) with 0.3-inch body width and through-hole mounting. Pin pitch is 0.1 inch; leads are tin-lead plated for standard wave soldering compatibility.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX144BEPA+, the MAX144AEPA+ provides tighter linearity for calibration-critical instrumentation; compared with ADS7822U, it integrates track/hold and supports lower source impedances without external components - reducing design risk in space-constrained portable systems.

Availability

MAX144AEPA+ is available at Aetrix Electronics and suitable for portable data logging, battery-powered instrumentation, and isolated data acquisition requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX144AEPA+ 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 series belongs to Maxim's low-power serial ADC product line, engineered specifically for space- and energy-constrained systems needing 12-bit accuracy without external support circuitry.

FAQ

What is the operating temperature range of the MAX144AEPA+?

The MAX144AEPA+ is rated for operation from -40°C to +85°C. This extended industrial temperature range is confirmed in the Ordering Information table and Absolute Maximum Ratings section of the official datasheet. The device maintains specified performance - including ±0.5 LSB INL and 108ksps sampling - across this full range, making it suitable for deployment in uncontrolled environments such as outdoor sensor nodes or factory-floor controllers. The 'E' grade suffix explicitly denotes this temperature capability.

Does the MAX144AEPA+ require an external reference voltage?

Yes, the MAX144AEPA+ requires an external reference voltage applied to the REF pin. It does not include an internal reference. The datasheet specifies that REF must be stable, capable of delivering 250µA DC load current, and have output impedance ≤10Ω to maintain 12-bit accuracy. A 0.1µF bypass capacitor is mandatory at the REF pin. Common choices include precision references like the MAX6126 or buffered DAC outputs - but the MAX144AEPA+ itself provides no on-chip reference generation.

How does channel selection work on the MAX144AEPA+?

The MAX144AEPA+ automatically alternates between CH0 and CH1 after power-on reset: first conversion is CH0, second is CH1, then repeats. To force conversion on a specific channel, toggle CS/SHDN twice - the first toggle starts CH0, the second starts CH0 again. CH0 and CH1 are independent single-ended inputs referenced to GND. Unlike the MAX145, the MAX144AEPA+ does not support pseudo-differential operation; CH1 is not used as CH− in this variant.

What is the minimum acquisition time required before a valid conversion on the MAX144AEPA+?

The MAX144AEPA+ requires a minimum acquisition time (tACQ) of 7µs, as specified in the Electrical Characteristics table. This is the time needed for the internal track/hold amplifier to settle the sampled voltage onto the 16pF hold capacitor. If the analog source impedance exceeds 1kΩ, tACQ increases per the formula tACQ = 9(RS + 9kΩ)(16pF); for example, a 10kΩ source raises tACQ to ~1.6µs longer. The 7µs value assumes low-impedance driving and is guaranteed across -40°C to +85°C.

Can the MAX144AEPA+ interface directly with a 3.3V microcontroller SPI port?

Yes, the MAX144AEPA+ can interface directly with a 3.3V microcontroller SPI port. Its digital inputs (CS/SHDN, SCLK) accept VIH ≥ 2.0V and VIL ≤ 0.8V at VDD = 3.3V, and its DOUT output drives VOH ≥ VDD − 0.5V (≥2.8V) and VOL ≤ 0.4V - fully compatible with standard 3.3V CMOS logic levels. No level-shifting circuitry is required. The device also supports CPOL = 0 and CPHA = 0 SPI mode, matching most MCU hardware SPI peripherals out-of-the-box.