Analog Devices Inc./Maxim Integrated MAX1249BEPE+

Overview

MAX1249BEPE+ 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 and battery-powered medical instruments requiring low power and compact size.

For engineers reviewing the MAX1249BEPE+ datasheet, MAX1249BEPE+ pinout, MAX1249BEPE+ application, or MAX1249BEPE+ 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 MAX1249BEPE+ uses successive-approximation architecture with an internal track/hold circuit that acquires input signals in ≤1.5µs and supports both internal clock (7.5µs max conversion time) and external clock (15-cycle, 2MHz) modes. Its analog front-end allows pseudo-differential sampling across CH0–CH3 with COM as reference, and features ±0.5LSB COM stability requirement for accurate conversions.

It implements a three-level SHDN pin enabling full power-down (1µA), fast power-down (54µA at 1ksps), or operational mode, while its REFADJ-controlled reference buffer supports ±1.5% adjustment of external VREF - critical for precision calibration in portable instrumentation where supply voltage varies.

Key Specifications

Pinout & Package

MAX1249BEPE+ is housed in a 16-pin QSOP package (5.3mm × 10.2mm footprint), occupying the same board area as an 8-pin SOIC - enabling space-constrained upgrades without layout redesign.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX1248BEPE+, the MAX1249BEPE+ trades integrated reference for external reference flexibility and tighter gain error control, while ADS7822U offers higher speed at lower resolution and lacks power management features essential for battery operation.

Availability

MAX1249BEPE+ is available at Aetrix Electronics and suitable for portable data logging, battery-powered medical instrumentation, and industrial system supervision requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for MAX1249BEPE+ 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 applications.

The MAX1248/MAX1249 product line was designed for low-power, multi-channel data acquisition in space- and energy-constrained portable systems - emphasizing software configurability, minimal external components, and robust serial interfacing.

FAQ

What is the reference configuration requirement for MAX1249BEPE+?

The MAX1249BEPE+ requires an external 2.500V reference applied to the VREF pin; it does not include an internal reference. The REFADJ pin allows ±1.5% adjustment of the reference buffer gain (2.00 V/V), enabling fine calibration against system-level tolerances. A 4.7µF capacitor must be placed at VREF for stability, and the reference must remain within ±50mV of 2.500V for specified accuracy. This differs from the MAX1248BEPE+, which integrates the 2.5V reference.

Does MAX1249BEPE+ support differential input mode, and how is it configured?

Yes, MAX1249BEPE+ supports pseudo-differential input mode across two channel pairs: CH0/CH1 and CH2/CH3. Configuration is done via the 8-bit control byte written to DIN: setting SGL/DIF = 0 selects differential mode, and SEL2–SEL0 bits choose the pair (e.g., 001 = CH0/CH1). During conversion, only the positive input (IN+) is sampled, while the negative input (IN-) must remain stable within ±0.5LSB relative to AGND - typically achieved with a 0.1µF capacitor from IN- to AGND.

What power-down modes does MAX1249BEPE+ offer, and how are they activated?

MAX1249BEPE+ offers two power-down modes controlled by the PD1/PD0 bits in the control byte: full power-down (PD1=0, PD0=0) draws 1µA, and external clock mode (PD1=1, PD0=1) enables active conversion. The SHDN pin provides hardware-level control: pulling it low forces full shutdown regardless of software state. Unlike the MAX1248, the MAX1249BEPE+ does not support fast power-down mode (PD1=0, PD0=1), as that feature is exclusive to the MAX1248 variant with internal reference.

Can MAX1249BEPE+ interface directly with a TMS320-family DSP, and what signal is required?

Yes, MAX1249BEPE+ can interface directly with TMS320-family DSPs using the SSTRB (serial strobe) output. In external clock mode, SSTRB pulses high for one SCLK period before the MSB appears on DOUT, providing precise timing for DSP capture. In internal clock mode, SSTRB goes low at conversion start and high at completion - enabling the DSP to poll or interrupt on SSTRB transition. No external logic or level shifters are needed, satisfying TI's serial port timing requirements for QSPI-compatible operation.

What is the maximum source impedance supported for accurate acquisition on MAX1249BEPE+?

The MAX1249BEPE+ specifies a minimum acquisition time (tACQ) of 1.5µs, calculated as tACQ = 7.6 × (RS + 9kΩ) × 16pF. For RS ≤3kΩ, AC performance remains unaffected; above that, acquisition time increases linearly. To maintain accuracy with higher source impedances (e.g., 10kΩ), a 0.01µF capacitor must be placed at each analog input to form an RC filter - though this limits input bandwidth. The COM node must also remain stable within ±0.5LSB, requiring low-impedance grounding.