Analog Devices Inc./Maxim Integrated MAX11643EEG+

Overview

MAX11643EEG+ from Maxim Integrated is a 8-bit, 16-channel successive-approximation ADC with integrated 2.5V reference, 16-entry FIFO, and SPI/QSPI/MICROWIRE-compatible 3-wire serial interface. It operates from 2.7V to 3.6V supply, achieves 300ksps sampling rate with external clock, and features AutoShutdown™, scan mode, and internal averaging. It is used in patient monitoring systems for multi-sensor analog signal digitization.

For engineers reviewing the MAX11643EEG+ datasheet, MAX11643EEG+ pinout, MAX11643EEG+ application, or MAX11643EEG+ equivalent, key selection considerations include unipolar 0–2.5V input range, 24-pin QSOP package compatibility, -40°C to +85°C industrial temperature operation, and FIFO-buffered burst acquisition without CPU bus contention.

Technical Context

The MAX11643EEG+ implements a SAR architecture with on-chip track-and-hold supporting single-ended inputs only. Its internal oscillator (±10% accuracy at 4.4MHz) enables autonomous conversions in clock modes 00/01/10, while clock mode 11 supports externally timed acquisitions up to 300ksps using SCLK ≤10MHz.

It integrates a 16-deep FIFO that stores full 16-bit result words (4 leading zeros + 8-bit data), enabling background scanning of up to 16 channels without serial bus occupation. Internal averaging (1–16 samples per result) and programmable scan depth (1–16 channels) are configured via dedicated setup and averaging registers.

Key Specifications

Pinout & Package

MAX11643EEG+ is housed in a 24-pin QSOP package (5.3mm × 7.2mm, 0.635mm pitch), optimized for high-density PCB layouts and reflow soldering. Pin functions are validated per Maxim's Rev 0 datasheet (19-6035).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 8-bit multichannel ADC applications.

Compared with ADS7822U and MAX11100ETE+, the MAX11643EEG+ uniquely combines 16-channel count, on-chip FIFO, and programmable scan/averaging - making it optimal for embedded systems needing autonomous, low-overhead analog monitoring without external logic.

Availability

MAX11643EEG+ is available at Aetrix Electronics and suitable for patient monitoring, industrial control systems, and data-logging applications requiring stable component supply, RoHS-compliant packaging, and guaranteed -40°C to +85°C operation.

Supply support for MAX11643EEG+ 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) is a semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for industrial, medical, and communications markets.

The MAX116xx family was designed for low-power, multi-channel system supervision in space- and energy-constrained applications - emphasizing integration (FIFO, reference, T/H), flexible timing, and robust industrial temperature operation.

FAQ

What is the maximum sampling rate achievable with MAX11643EEG+?

The MAX11643EEG+ achieves a maximum sampling rate of 300ksps when using an external clock (SCLK ≤10MHz, clock mode 11). In internally clocked modes (00/01/10), the effective rate is lower due to oscillator tolerance and conversion overhead; typical sustained throughput is ~200ksps for continuous FIFO reads. The MAX11643EEG+ datasheet specifies 300ksps as the absolute maximum under defined timing conditions.

Does MAX11643EEG+ support differential input configurations?

No, the MAX11643EEG+ supports single-ended analog inputs only, referenced to GND. Its internal architecture uses a true differential track-and-hold stage, but the negative input is hardwired to GND - resulting in unipolar 0–VREF operation. Differential signaling or bipolar input ranges are not supported; external signal conditioning is required for such use cases.

How does the FIFO function in MAX11643EEG+ during continuous scanning?

In MAX11643EEG+, the 16-entry FIFO stores full 16-bit result words (4 leading zeros + 8-bit data). During continuous scanning, new conversions overwrite the oldest unread result when the FIFO is full. After each CS low-to-high transition, the oldest available byte is presented at DOUT. This enables background acquisition while the host processor handles other tasks - reducing interrupt load and improving deterministic timing.

What is the purpose of the CNVST/AIN15 pin on MAX11643EEG+?

The CNVST/AIN15 pin on MAX11643EEG+ serves a dual role: as an active-low hardware conversion trigger (CNVST) or as the 16th analog input (AIN15). Configuration is controlled by the setup register (bit REFSEL0). When used as CNVST, it initiates conversions without serial bus activity - ideal for event-driven sampling. As AIN15, it extends the channel count to 16, matching the device's full specification.

Can MAX11643EEG+ operate with an external reference voltage?

Yes, the MAX11643EEG+ accepts an external reference voltage applied to the REF pin, ranging from 1.0V to VDD. When using an external reference, the internal 2.5V reference is disabled. This allows customization of full-scale range (e.g., 0–3.0V for 3.3V systems) and improved accuracy if a higher-precision external reference is available. The REF input current remains low (±0.1µA typical), minimizing loading effects.