Analog Devices Inc./Maxim Integrated MAX1249BEEE+

Overview

MAX1249BEEE+ from Maxim Integrated is a 10-bit, 4-channel serial analog-to-digital converter (ADC) with integrated track/hold, software-configurable unipolar/bipolar and single-ended/differential inputs, and SPI/QSPI/MICROWIRE-compatible 4-wire interface. It operates from a single +2.7V to +5.25V supply, consumes only 54µA at 1ksps (+3V), and supports external reference input at VREF pin. It is used in portable data loggers and battery-powered medical instrumentation where low power and compact size are critical.

For engineers reviewing the MAX1249BEEE+ datasheet, MAX1249BEEE+ pinout, MAX1249BEEE+ application, or MAX1249BEEE+ equivalent, this page delivers verified technical context, real-world design meaning for key specs, validated QSOP-16 pin functions, confirmed alternative parts with documented functional differences, and supply-chain support details specific to OEM and embedded design use cases.

Technical Context

The MAX1249BEEE+ uses successive-approximation architecture with an internal track/hold circuit that acquires input signals in ≤1.5µs and supports both internal clock mode (7.5µs max conversion time) and external clock mode (15 clocks/conversion at 2MHz). Its analog front-end accepts up to four single-ended or two differential inputs, with COM pin serving as common-mode reference and configurable via control byte bits SEL2–SEL0 and SGL/DIF.

It requires an external 2.500V reference applied to the VREF pin, features a reference-buffer amplifier with ±1.5% adjustment range via REFADJ, and provides SHDN pin for three-level shutdown control (low = full power-down, high = internal compensation, float = external compensation). Digital interface timing complies with SPI (CPOL=0, CPHA=0), QSPI, and MICROWIRE protocols without external logic.

Key Specifications

Pinout & Package

MAX1249BEEE+ is housed in a 16-pin QSOP package (5.3mm × 10.2mm footprint, same board area as 8-pin SO), optimized for space-constrained portable designs.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 10-bit serial ADC applications.

Compared with MAX1249BEEE+, MAX1248BEEE+ trades external reference flexibility for integration and higher active current, while ADS7822U offers greater resolution but removes programmable input configuration and low-power shutdown - making MAX1249BEEE+ optimal for battery-powered, multi-mode sensing where reference stability and ultra-low standby current are essential.

Availability

MAX1249BEEE+ is available at Aetrix Electronics and suitable for portable data logging, battery-powered medical instrumentation, and industrial system supervision requiring stable component supply across production lifecycles.

Supply support for MAX1249BEEE+ 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 demanding industrial, medical, and portable applications.

The MAX1248/MAX1249 product line delivers low-power, multi-channel serial ADCs optimized for space- and energy-constrained embedded systems requiring flexible input configuration and robust reference handling.

FAQ

What is the reference voltage requirement for MAX1249BEEE+?

The MAX1249BEEE+ requires an external 2.500V reference applied to the VREF pin. Unlike the MAX1248 variant, it does not include an internal reference. The reference must be stable within ±0.030V (±1.2%) and sourced with ≤0.2mA load; the REFADJ pin allows ±1.5% fine adjustment when the internal buffer is enabled, but for MAX1249BEEE+, the buffer is typically disabled by tying REFADJ to VDD.

How does the SHDN pin function on MAX1249BEEE+?

The SHDN pin on MAX1249BEEE+ provides three-level control: pulled low → full power-down (1µA supply current); pulled high → internal compensation mode for reference buffer; left floating → external compensation mode. This enables precise power-state management without external logic, supporting rapid wake-up (<1.5µs acquisition time) and configurable reference buffering depending on external circuit needs.

Can MAX1249BEEE+ operate in differential input mode?

Yes, MAX1249BEEE+ supports pseudo-differential input mode using CH0/CH1 or CH2/CH3 pairs. In this mode, the voltage difference |IN+ − IN−| is sampled, with IN− required to remain stable within ±0.5LSB relative to AGND. A 0.1µF capacitor from the selected IN− channel to AGND is mandatory to maintain accuracy; the control byte's SGL/DIF bit (bit 2) must be set to '0' to enable differential operation.

What serial interface protocols does MAX1249BEEE+ support?

MAX1249BEEE+ supports SPI (CPOL=0, CPHA=0), QSPI, and MICROWIRE protocols natively via its 4-wire interface (SCLK, DIN, DOUT, CS). No external logic is needed for protocol translation. The SSTRB pin also enables direct interfacing with TMS320-family DSPs. Data is clocked MSB-first, with DOUT valid on SCLK falling edges and DIN sampled on rising edges - matching standard master-slave timing conventions.

What is the maximum sampling rate of MAX1249BEEE+ and what limits it?

The MAX1249BEEE+ achieves a maximum sampling rate of 133ksps using a 2.0MHz external serial clock with 15 clocks per conversion cycle. This rate is limited by the internal successive-approximation algorithm timing and the 1.5µs minimum track/hold acquisition time. At lower clock frequencies (<100kHz), internal clock mode must be used to avoid conversion droop; in that mode, the effective rate drops to ~130ksps due to fixed 7.5µs conversion time.