Analog Devices Inc./Maxim Integrated MAX1249AEPE+

Overview

MAX1249AEPE+ from Maxim Integrated is a 10-bit, 4-channel serial analog-to-digital converter (ADC) with integrated track/hold, multiplexer, and SPI/QSPI/MICROWIRE-compatible 4-wire interface. It operates from a single +2.7V to +5.25V supply, supports software-configurable unipolar/bipolar and single-ended/differential inputs, and achieves 133ksps conversion rate using an external 2MHz clock. It is used in portable data loggers requiring low-power, high-accuracy digitization of sensor signals.

For engineers reviewing the MAX1249AEPE+ datasheet, MAX1249AEPE+ pinout, MAX1249AEPE+ application, or MAX1249AEPE+ equivalent, this page delivers verified technical context, real-world design meaning for key specs, validated QSOP-16 pin functions, confirmed alternative parts with documented differences, and supply support details for industrial and battery-powered systems.

Technical Context

The MAX1249AEPE+ uses successive-approximation architecture with an internal track/hold circuit that acquires input signals in ≤1.5µs and supports pseudo-differential sampling across CH0–CH3. Its analog front-end accepts inputs from AGND to VDD in single-ended mode or ±VREF/2 in bipolar differential mode, with COM pin serving as common-mode reference.

It features dual clock modes: external clock (2MHz max, drives conversion timing) and internal clock (self-timed, enables flexible readout). The device requires an external 2.500V reference applied at VREF and includes a REFADJ-adjustable reference buffer with ±1.5% voltage tuning range and ±30ppm/°C temperature coefficient.

Key Specifications

Pinout & Package

MAX1249AEPE+ is housed in a 16-pin QSOP package (5.3mm × 10.0mm 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 MAX1248AEPE+, MAX1249AEPE+ trades integrated reference for external reference flexibility and lower active current; compared with ADS7822U, it offers configurable input modes and reference tuning at the cost of 2-bit resolution - making it optimal for multi-sensor, battery-aware, and calibration-sensitive applications.

Availability

MAX1249AEPE+ is available at Aetrix Electronics and suitable for portable data logging, medical instrumentation, and battery-powered instrumentation requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.

Supply support for MAX1249AEPE+ 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 portable applications.

The MAX1248/MAX1249 product line was designed for low-power, multi-channel data acquisition in space- and energy-constrained systems, emphasizing software configurability, small footprint, and robust serial interfacing without external logic.

FAQ

What is the reference requirement for MAX1249AEPE+?

The MAX1249AEPE+ requires an external 2.500V reference applied to the VREF pin. It does not include an internal reference - unlike the MAX1248AEPE+. The reference must be stable within ±0.030V and capable of sourcing up to 150µA. The REFADJ pin allows ±1.5% fine adjustment of the reference buffer gain, enabling system-level calibration. This external reference architecture supports shared reference schemes and improves noise immunity versus supply-referred designs.

Does MAX1249AEPE+ support differential input mode?

Yes, the MAX1249AEPE+ supports pseudo-differential input mode via software configuration. Setting SGL/DIF = 0 in the control byte selects differential operation, allowing measurements across CH0/CH1 or CH2/CH3 pairs. In this mode, the positive input (IN+) is sampled while the negative input (IN−) serves as a stable common-mode reference; IN− must remain within ±0.5LSB of AGND during conversion. A 0.1µF capacitor from IN− to AGND is recommended to maintain stability.

What is the minimum acquisition time for MAX1249AEPE+?

The guaranteed minimum acquisition time (tACQ) for MAX1249AEPE+ is 1.5µs. This is the shortest time required for the internal track/hold circuit to settle after the last bit of the control byte is clocked in. For source impedances above 3kΩ, tACQ increases per tACQ = 7.6 × (RS + 9kΩ) × 16pF. If the total conversion interval exceeds 120µs, T/H droop may degrade accuracy - so internal clock mode is recommended for low or interrupted SCLK frequencies.

How does the SHDN pin function on MAX1249AEPE+?

The SHDN pin on MAX1249AEPE+ is a three-level control: pulled low → full power-down (1µA); left floating → external compensation mode for REFADJ; pulled high → internal compensation mode. Unlike simple on/off shutdown, this pin also configures the reference buffer's compensation network. In all states, asserting CS low automatically powers up the device, and the quick turn-on time (<1µs) permits powering down between individual conversions to minimize average current.

Which serial protocols is MAX1249AEPE+ compatible with?

The MAX1249AEPE+ is natively compatible with SPI, QSPI, and MICROWIRE protocols via its 4-wire interface (SCLK, DIN, DOUT, CS). It requires CPOL = 0 and CPHA = 0 for SPI. The SSTRB output enables direct connection to TMS320-family DSPs. No external logic is needed - the interface handles control byte framing, 10-bit result alignment, and tri-state control automatically. Data is clocked MSB-first on SCLK falling edges, with DOUT high-Z when CS is high.