Analog Devices Inc./Maxim Integrated MAX1241AESA+

Overview

MAX1241AESA+ from Maxim Integrated is a low-power, 12-bit successive-approximation analog-to-digital converter (ADC) with 73ksps throughput, 7.5µs conversion time, and SPI/QSPI/MICROWIRE-compatible 3-wire serial interface. It operates from a single +2.7V to +5.25V supply, requires an external reference (0V to VREF input range), and targets space-constrained, battery-powered data acquisition systems.

For engineers reviewing the MAX1241AESA+ datasheet, MAX1241AESA+ pinout, MAX1241AESA+ application, or MAX1241AESA+ equivalent, this page delivers verified electrical specs, validated SO-8 pin mapping, real-world use cases in isolated sensing and portable instrumentation, and two confirmed alternative ADCs with documented functional and interface differences.

Technical Context

The MAX1241AESA+ implements a track/hold circuit with 1.5µs acquisition time and a 12-bit SAR core clocked by an internal oscillator. Its unipolar transfer function maps 0V–VREF inputs to 0x000–0xFFF codes, with DOUT outputting MSB-first serial data synchronized to SCLK falling edges.

It supports three operational states: active conversion (73ksps, 3mW at VDD = 3.6V), standby (1.9mA), and shutdown (2µA). The SHDN pin controls power state and-unlike the MAX1240-does not enable/disable internal reference, as the MAX1241AESA+ lacks on-chip reference and mandates external VREF between +1.0V and VDD.

Key Specifications

Pinout & Package

MAX1241AESA+ is housed in an 8-pin SO (Small Outline) package with standard JEDEC MS-012AC footprint (5.0mm × 4.0mm, 1.27mm pitch).

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADS7822U and AD7476AARMZ, the MAX1241AESA+ uniquely balances ultra-low 2µA shutdown current, multi-protocol serial compatibility, and external reference flexibility-making it optimal for battery longevity and design reuse across legacy µC platforms.

Availability

MAX1241AESA+ is available at Aetrix Electronics and suitable for battery-powered systems, portable data logging, isolated data acquisition, and process control requiring stable component supply across industrial temperature ranges (–40°C to +85°C).

Supply support for MAX1241AESA+ 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 and mixed-signal ICs for demanding industrial, medical, and communications applications.

The MAX1240/MAX1241 family was engineered specifically for low-power, space-constrained data acquisition-emphasizing single-supply operation, integrated track/hold, and protocol-flexible serial interfaces in minimal 8-pin packages.

FAQ

What is the reference voltage requirement for MAX1241AESA+?

The MAX1241AESA+ requires an external reference voltage applied to the REF pin, ranging from +1.0V to VDD. It does not include an internal reference. For optimal performance, the external reference must provide ≤10Ω output impedance and sustain ≥250µA DC load during conversion. A minimum 0.1µF ceramic bypass capacitor is mandatory at the REF pin; a 4.7µF capacitor is recommended if the reference is noisy or high-impedance. The MAX1241AESA+ achieves ±0.5 LSB INL only when VREF is stable and within specification.

Does MAX1241AESA+ support SPI, QSPI, and MICROWIRE protocols simultaneously?

Yes, the MAX1241AESA+ serial interface is electrically and timing-compatible with SPI (CPOL=0, CPHA=0), QSPI, and MICROWIRE standards. It uses a 3-wire configuration (SCLK, CS, DOUT) with MSB-first unipolar output. While all three protocols share the same physical signaling, QSPI allows full 12-bit readout in exactly 13 clock cycles without trailing zeros, whereas SPI and MICROWIRE typically require two byte reads with padding. No hardware reconfiguration is needed-the host controller selects the protocol via software timing.

What is the minimum acquisition time for MAX1241AESA+ and how does source impedance affect it?

The guaranteed maximum acquisition time (t_ACQ) for MAX1241AESA+ is 1.5µs. However, actual acquisition time depends on analog source impedance (R_S) and is calculated as t_ACQ = 9(R_S + 9kΩ) × 16pF. For R_S < 1kΩ, t_ACQ remains near 1.5µs and does not degrade AC performance. For higher impedances, a 0.01µF capacitor at AIN is recommended to maintain accuracy-but this forms an RC filter that limits input bandwidth. Therefore, the MAX1241AESA+ performs best with low-impedance sources or buffered inputs.

Can MAX1241AESA+ operate from a 5V supply while using a 2.5V reference?

Yes, the MAX1241AESA+ supports VDD = +5.25V while accepting VREF = +2.5V. Its REF input range explicitly includes voltages from +1.0V to VDD, enabling ratiometric configurations where VREF is derived independently (e.g., from a precision bandgap). When VDD = 5V and VREF = 2.5V, the device digitizes 0V–2.5V analog inputs with full 12-bit resolution and maintains ±0.5 LSB INL. Power dissipation increases to ~3.5mW at 73ksps, remaining well within SO-8 thermal limits.

How does the SHDN pin function on MAX1241AESA+ compared to MAX1240?

On the MAX1241AESA+, the SHDN pin operates solely as a three-level shutdown control: pulled low → 2µA shutdown; high or open → active mode. Unlike the MAX1240, it has no internal reference to enable/disable-so SHDN state does not affect reference configuration. This simplifies design for external-reference systems. The MAX1241AESA+ wakes from shutdown in 4µs (vs. up to 20ms for MAX1240 with discharged 4.7µF cap), making it superior for rapid duty-cycled sampling in battery-powered applications.