Analog Devices Inc./Maxim Integrated MAX11638EEE+T

Overview

MAX11638EEE+T from Maxim Integrated is an 8-bit, 8-channel serial analog-to-digital converter (ADC) with integrated track-and-hold, 16-entry FIFO, internal 4.096V reference, and SPI/QSPI/MICROWIRE-compatible 3-wire interface. It operates from a +4.75V to +5.25V supply, achieves up to 300ksps sampling rate with external clocking, and delivers ±0.5 LSB INL/DNL accuracy over –40°C to +85°C. It is used in industrial control systems for real-time sensor voltage digitization.

For engineers reviewing the MAX11638EEE+T datasheet, MAX11638EEE+T pinout, MAX11638EEE+T application, or MAX11638EEE+T equivalent, key selection considerations include its unipolar 0–VREF input range, internal reference stability (±20 ppm/°C), FIFO buffering for burst acquisition, AutoShutdown™ current reduction to 0.2 µA, and QSOP-16 package compatibility with space-constrained PCB layouts.

Technical Context

The MAX11638EEE+T employs a successive-approximation register (SAR) architecture with on-chip track-and-hold, supporting single-ended unipolar inputs referenced to GND. Its internal 4.096V reference provides stable full-scale range without external components, and its 16-entry FIFO enables autonomous multi-sample acquisition without serial bus contention.

It supports four programmable clock modes via CKSEL bits: mode 00 uses CNVST/AIN7 as conversion trigger with internal timing; mode 01 enables per-channel conversion start; mode 10 initiates conversions via serial write; mode 11 enables externally clocked 300ksps operation at up to 10MHz SCLK - disabling scan/average but maximizing throughput.

Key Specifications

Pinout & Package

MAX11638EEE+T 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 8-bit multichannel ADC applications.

Compared with ADS7822U and MAX11100ETE+, the MAX11638EEE+T uniquely combines 8-channel count, internal 4.096V reference, 16-deep FIFO, and 5V operation - making it optimal for cost-sensitive, space-constrained industrial controllers requiring autonomous multi-sample acquisition without external support components.

Availability

MAX11638EEE+T is available at Aetrix Electronics and suitable for industrial control systems, data-acquisition systems, and patient monitoring devices requiring stable component supply, RoHS-compliant packaging, and long-term production continuity.

Supply support for MAX11638EEE+T 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 precision analog, mixed-signal, and power management ICs for industrial, medical, and communications applications.

The MAX11638EEE+T belongs to Maxim's low-power, multichannel ADC product line designed for system supervision and embedded data acquisition where integration, small size, and supply flexibility are critical.

FAQ

What is the maximum sampling rate achievable with the MAX11638EEE+T?

The MAX11638EEE+T achieves a maximum sampling rate of 300ksps when using an external clock in clock mode 11 (CKSEL = 11). This requires SCLK up to 10MHz with 40–60% duty cycle and disables scan mode and internal averaging. At lower rates, internal clocking supports autonomous operation with FIFO buffering - a key advantage of the MAX11638EEE+T in resource-constrained systems.

Does the MAX11638EEE+T require an external reference voltage?

No, the MAX11638EEE+T includes an internal 4.096V reference with ±0.7% initial accuracy and ±20 ppm/°C temperature coefficient, eliminating the need for external reference components. The REF pin must still be bypassed with a 0.1µF capacitor to GND. An external reference (1V to VDD) can be used instead, but doing so disables the internal reference and forfeits its stability benefits - a trade-off not required for most MAX11638EEE+T deployments.

How does the FIFO function in the MAX11638EEE+T improve system design?

The 16-entry FIFO in the MAX11638EEE+T stores complete 16-bit conversion results (4 leading zeros + 8-bit code) without host intervention, enabling burst acquisition sequences. This decouples sampling from serial readout - reducing MCU interrupt frequency by up to 16× and simplifying real-time scheduling. When the FIFO fills, new results overwrite oldest entries, ensuring continuous data flow in logging or monitoring applications using the MAX11638EEE+T.

What are the valid supply voltage ranges for the MAX11638EEE+T?

The MAX11638EEE+T operates from a single +4.75V to +5.25V supply, as confirmed in the Ordering Information table and Electrical Characteristics section. This 5V-compatible range distinguishes it from the MAX11639EEE+T (2.7–3.6V) and ensures interoperability with legacy 5V logic and power domains. Operation outside this range risks damage or specification violation - the absolute maximum rating is +6V, but functional operation is guaranteed only within the 4.75–5.25V window for the MAX11638EEE+T.

Can the MAX11638EEE+T perform differential measurements?

No, the MAX11638EEE+T supports only single-ended unipolar analog inputs (0 to VREF) referenced to GND, as explicitly stated in the "Unipolar" section and Functional Diagram. Its input architecture uses a single T/H with positive input tied to AINx and negative input fixed to GND - it lacks true differential input pairs or programmable gain instrumentation amplifier stages. For differential measurement requirements, a separate signal conditioning stage or alternative ADC such as the MAX11610 would be necessary; the MAX11638EEE+T is optimized for cost-effective single-ended sensor interfacing.