Analog Devices Inc./Maxim Integrated MAX11635EEE+

Overview

The MAX11635EEE+ from Maxim Integrated is a 12-bit, 300ksps successive-approximation ADC with true differential track/hold, internal 2.5V reference, and 4 single-ended / 2 differential input channels. It operates from a 2.7V–3.6V supply, features 16-entry FIFO, internal averaging, and SPI/QSPI/MICROWIRE-compatible 3-wire serial interface. It targets precision analog monitoring in compact industrial sensor nodes.

For engineers reviewing the MAX11635EEE+ datasheet, MAX11635EEE+ pinout, MAX11635EEE+ application, or MAX11635EEE+ equivalent, key selection criteria include its ±1 LSB INL/DNL accuracy over –40°C to +85°C, 71dB SINAD at 30kHz, low 1.2mA typical supply current at 300ksps (internal reference), and QSOP-16 package compatibility with space-constrained PCB layouts.

Technical Context

The MAX11635EEE+ implements a fully differential SAR architecture with on-chip track-and-hold supporting both unipolar (0 to VREF) and bipolar (±VREF/2) differential modes, plus single-ended GND-referenced operation. Its internal 2.5V reference exhibits ±30ppm/°C drift and 200µVRMS noise.

It supports four clock modes via CKSEL bits: mode 00 enables CNVST-triggered conversions; mode 01 allows per-channel CNVST control; mode 10 uses serial-register-initiated conversions; mode 11 enables externally clocked 300ksps sampling with SCLK up to 4.8MHz - disabling scan and averaging but maximizing throughput.

Key Specifications

Pinout & Package

MAX11635EEE+ is housed in a 16-pin QSOP (Quad Small Outline Package) with 0.154" body width and 0.025" lead pitch, optimized for automated assembly and thermal performance (θJA = 105°C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADS7953IRHBT and AD7476AARMZ, the MAX11635EEE+ uniquely integrates internal 2.5V reference, true differential track/hold, 16-entry FIFO, and AutoShutdown™ in a 4-channel device - optimizing BOM cost, layout area, and power efficiency for mid-channel-count industrial and medical monitoring.

Availability

MAX11635EEE+ is available at Aetrix Electronics and suitable for industrial process monitoring, patient vital sign acquisition, environmental data logging, and smart building HVAC control requiring stable component supply and long-term production continuity.

Supply support for MAX11635EEE+ 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 industrial, medical, and communications applications.

The MAX11634–MAX11637 product line delivers low-power, multichannel SAR ADCs with integrated reference and FIFO - engineered for high-accuracy sensor interfacing in space- and power-constrained embedded systems.

FAQ

What is the maximum sampling rate achievable with the MAX11635EEE+?

The MAX11635EEE+ achieves a maximum sampling rate of 300ksps when using an external clock in clock mode 11. This requires SCLK up to 4.8MHz with 50% duty cycle. Internally clocked modes support lower rates (e.g., ~250ksps nominal) due to oscillator tolerance. The 300ksps rate enables digitization of signals with up to 100kHz full-linear bandwidth, making MAX11635EEE+ suitable for dynamic sensor monitoring.

Does the MAX11635EEE+ require an external reference voltage?

No, the MAX11635EEE+ includes a factory-trimmed internal 2.50V reference with ±20mV initial accuracy and ±30ppm/°C temperature coefficient. External reference is optional via REF+ pin (1V to VDD range) and is only needed when higher precision or different reference voltage is required. Using the internal reference eliminates external components and simplifies layout - a key advantage of MAX11635EEE+ in cost-sensitive designs.

How does the FIFO buffer in the MAX11635EEE+ improve system performance?

The 16-entry FIFO in MAX11635EEE+ stores conversion results without CPU intervention, allowing continuous sampling while the host processor handles other tasks. This decouples acquisition from data readout, reducing firmware latency and preventing data loss during brief MCU sleep or interrupt service. Each FIFO entry holds a 16-bit result (MSB first), and overflow overwrites oldest data - enabling robust burst-mode operation in MAX11635EEE+ data loggers and real-time controllers.

Can the MAX11635EEE+ perform true differential measurements?

Yes, the MAX11635EEE+ supports true differential measurements using AIN0/AIN1 and AIN2/AIN3 input pairs. In differential mode, it samples the voltage difference between paired inputs, rejecting common-mode noise and DC offsets. The device supports both unipolar (0 to VREF) and bipolar (±VREF/2) differential ranges, with output in binary or two's complement format respectively. This capability makes MAX11635EEE+ ideal for bridge sensor and isolated signal conditioning applications.

What power-saving features does the MAX11635EEE+ offer for battery-powered applications?

The MAX11635EEE+ includes AutoShutdown™ mode, reducing supply current to ≤5µA during idle periods. It also supports configurable internal clock modes that minimize active time, and internal averaging that allows lower sampling rates without sacrificing SNR. With typical active current of 1.2mA at 300ksps (internal reference), MAX11635EEE+ enables multi-year battery life in environmental sensors and portable medical devices when combined with intelligent wake/sleep firmware.