Analog Devices Inc./Maxim Integrated MAX1249AEEE+T

Overview

MAX1249AEEE+T 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 with 1.2mA supply current at +3V - enabling high-precision data acquisition in battery-powered medical instruments and portable data loggers.

For engineers reviewing the MAX1249AEEE+T datasheet, MAX1249AEEE+T pinout, MAX1249AEEE+T application, or MAX1249AEEE+T equivalent, this page delivers verified technical context, real-world timing behavior, reference-buffer configuration constraints, and validated alternative options for low-power, multi-channel ADC selection in space-constrained QSOP-16 designs.

Technical Context

The MAX1249AEEE+T 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 SCLK cycles per conversion). Its analog front-end accepts up to ±VREF/2 differential or 0V–VREF single-ended inputs, with COM pin serving as zero-code reference and requiring stability within ±0.5LSB.

Unlike the MAX1248, the MAX1249AEEE+T requires an external reference voltage applied to VREF (2.500V typical), and its REFADJ pin enables ±1.5% adjustment of the reference buffer gain only when the internal buffer is enabled - but the MAX1249's internal buffer must be disabled by tying REFADJ to VDD, making REFADJ functionally inactive in standard operation.

Key Specifications

Pinout & Package

MAX1249AEEE+T is housed in a 16-pin QSOP package (5.3mm × 10.2mm footprint, same board area as 8-pin SO), optimized for compact portable instrumentation layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX1248ACEE+, the MAX1249AEEE+T trades integrated reference convenience for guaranteed external reference stability and reduced internal drift sensitivity; versus ADS7822U, it offers superior input flexibility and deterministic strobe signaling at the cost of 2-bit resolution.

Availability

MAX1249AEEE+T is available at Aetrix Electronics and suitable for portable data logging, battery-powered instrumentation, and medical device design requiring stable component supply, long-term lifecycle support, and RoHS-compliant QSOP packaging.

Supply support for MAX1249AEEE+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) designs precision analog, mixed-signal, and power-management ICs for demanding industrial, medical, and communications applications.

The MAX1249AEEE+T belongs to Maxim's low-power serial ADC product line, engineered specifically for space-constrained, battery-operated systems requiring configurable multi-channel digitization without sacrificing AC performance or supply efficiency.

FAQ

What is the reference configuration requirement for MAX1249AEEE+T?

The MAX1249AEEE+T requires an external 2.500V reference applied directly to the VREF pin. Unlike the MAX1248, it does not include an internal reference; its REFADJ pin must be tied to VDD to disable the reference buffer, making it non-adjustable. This configuration ensures stable, low-drift reference performance independent of VDD variation.

Does MAX1249AEEE+T support both unipolar and bipolar input modes?

Yes, the MAX1249AEEE+T supports both unipolar (0V to VREF) and bipolar (–VREF/2 to +VREF/2) input ranges, selected dynamically via the UNI/BIP bit in the 8-bit control byte. In bipolar mode, the COM pin serves as the mid-scale reference point, and system layout must ensure COM stability within ±0.5LSB to maintain DC accuracy.

What is the minimum acquisition time for MAX1249AEEE+T, and how does source impedance affect it?

The MAX1249AEEE+T specifies a minimum acquisition time (tACQ) of 1.5µs. For higher source impedances, tACQ increases per tACQ = 7.6 × (RS + 9kΩ) × 16pF. Source impedances below 3kΩ have negligible impact on AC performance; above that, a 0.01µF capacitor per input is recommended to maintain bandwidth and reduce settling error.

Can MAX1249AEEE+T operate in internal clock mode, and what are the timing implications?

Yes, MAX1249AEEE+T supports internal clock mode (PD1/PD0 = 10), generating its own conversion clock. Conversion completes within 7.5µs (SHDN = FLOAT), and SSTRB goes low at start and high at completion. During this time, SCLK must remain low for optimal noise immunity; data is clocked out afterward at any rate ≤2MHz, enabling flexible host processor scheduling.

How is differential mode implemented on MAX1249AEEE+T, and what are the channel pairings?

Differential mode on MAX1249AEEE+T uses two fixed channel pairs: CH0/CH1 and CH2/CH3 - selected by SGL/DIF = 0 and appropriate SEL2–SEL0 bits. The architecture is pseudo-differential: only the positive input (IN+) is actively sampled, while the negative input (IN–) must remain stable within ±0.5LSB relative to AGND, typically enforced with a 0.1µF capacitor to AGND on the IN– line.