Analog Devices Inc./Maxim Integrated MAX11040GUU+

Overview

MAX11040GUU+ from Maxim Integrated is a 24-bit, 4-channel, simultaneous-sampling sigma-delta ADC with cascading capability for up to 32 synchronized channels, 117dB SNR at 1ksps, ±2.2V differential input range using internal 2.5V reference, and ±6V overvoltage protection on all analog inputs - deployed in precision energy metering and multiphase power monitoring systems.

For engineers reviewing the MAX11040GUU+ datasheet, MAX11040GUU+ pinout, MAX11040GUU+ application, or MAX11040GUU+ equivalent, this page delivers verified technical context, exact pin functions, real-world application mappings, and two validated alternative parts - all grounded in the official MAX11040K/MAX11060 datasheet (Rev 4, 5/15) and Maxim's published electrical characteristics.

Technical Context

The MAX11040GUU+ integrates four independent sigma-delta modulators with dedicated digital decimation filters, each supporting fully differential analog inputs and programmable sampling phase delay (0–333μs in 1.33μs steps) for compensation of external signal-path phase shifts. Its internal crystal oscillator (24.576MHz) or external clock drives a fixed ÷8 modulator clock, enabling precise timing control across cascaded devices.

It implements a SPI/QSPI/MICROWIRE/DSP-compatible 4-wire serial interface with single-CS daisy-chain support for up to eight devices, where CASCIN/CASCOUT coordinate data transfer sequencing, and SYNC enables periodic alignment of conversion timing across distributed units using a remote source.

Key Specifications

Pinout & Package

MAX11040GUU+ is housed in a 38-pin TSSOP package (JEDEC MO-153), with separate analog/digital ground planes (AGND/DGND), dual supply rails (AVDD, DVDD), and dedicated buffered reference outputs per channel (REF0–REF3).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-accuracy simultaneous-sampling ADC applications.

Compared with MAX11060GUU+, the MAX11040GUU+ provides 22dB higher SNR for harmonic-rich power waveforms, while AD7606C-24BSTZ offers double the channel count but lacks integrated phase compensation and hardware cascade control - making MAX11040GUU+ optimal for synchronized, high-fidelity multi-phase energy measurement.

Availability

MAX11040GUU+ is available at Aetrix Electronics and suitable for power-protection relay equipment, multiphase power systems, and industrial data-acquisition systems requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MAX11040GUU+ 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 industrial, automotive, and communications applications, with emphasis on high-reliability, low-power, and system-level integration.

The MAX11040GUU+ belongs to Maxim's high-accuracy energy measurement ADC family, engineered specifically for revenue-grade metering, protective relaying, and power quality analyzers demanding simultaneous sampling, phase coherence, and robust field survivability.

FAQ

What is the maximum number of MAX11040GUU+ devices that can be cascaded, and how does it affect the serial interface?

Up to eight MAX11040GUU+ devices can be cascaded using CASCIN/CASCOUT signals, allowing synchronized sampling across 32 analog channels. The serial interface behaves as a single logical device: one CS assertion and a single command sequence reads data from all cascaded units. No additional chip selects or address decoding are required - the daisy-chain eliminates software overhead and ensures deterministic timing alignment across the entire chain.

Does MAX11040GUU+ support external reference voltage, and what are the valid input specifications?

Yes, MAX11040GUU+ supports external reference via the REFIO pin, accepting 2.3V to 2.7V with ±200µA sink/source capability and 10pF input capacitance. When using external reference, the internal 2.5V buffer is disabled. This mode is used when higher initial accuracy or lower drift than the internal reference (50ppm/°C) is required - for example, when paired with a precision 2.5V reference IC like the ADR4525.

How does the programmable sampling phase in MAX11040GUU+ improve measurement accuracy in transformer-coupled systems?

The MAX11040GUU+ allows per-channel sampling phase adjustment from 0 to 333μs in 1.33μs steps. In transformer-coupled systems, this compensates for fixed group delay introduced by CT/PT windings and anti-aliasing filters - restoring phase coherence between voltage and current waveforms. Without this, phase errors >0.1° would degrade power factor and reactive power calculations, especially at harmonic frequencies.

What is the function of the FAULT and OVRFLW pins on MAX11040GUU+, and how are they electrically implemented?

FAULT is an open-drain output that goes low when any analog input exceeds ±2.25V/∓2.65V thresholds; OVRFLW goes low on data overflow or when FAULT asserts. Both include 30kΩ internal pullups, enabling wire-NOR fault aggregation across multiple MAX11040GUU+ devices. This simplifies system-level fault detection - a single MCU GPIO can monitor combined status without discrete OR gates or additional logic.

Can MAX11040GUU+ operate without an external crystal, and what are the clocking options?

Yes, MAX11040GUU+ can operate without an external crystal. It supports two clock sources: (1) internal crystal oscillator (enabled via XTALEN bit) with 24.576MHz crystal between XIN/XOUT, or (2) external CMOS clock applied directly to XIN (XOUT left unconnected). The modulator clock is always derived as f_XIN/8, so external clock must be 24.576MHz for nominal 3.072MHz modulator rate and 16ksps output data rate.