Analog Devices Inc./Maxim Integrated MAX1281BEUP+T

Overview

The MAX1281BEUP+T from Maxim Integrated is a 12-bit, 300ksps successive-approximation analog-to-digital converter (ADC) with integrated 8-channel multiplexer, track/hold, and SPI/QSPI/MICROWIRE-compatible 4-wire serial interface. It operates from a single +2.7V to +3.6V supply, features an internal +2.5V reference (±1.5% adjustable), supports software-configurable unipolar/bipolar and single-ended/pseudo-differential inputs, and delivers ±1 LSB INL over –40°C to +85°C - ideal for battery-powered medical instruments and portable data loggers.

For engineers reviewing the MAX1281BEUP+T datasheet, MAX1281BEUP+T pinout, MAX1281BEUP+T application, or MAX1281BEUP+T equivalent, this page provides verified technical context, real-world design meaning of key specs, validated pin functions, confirmed alternative parts with documented differences, and supply-chain support tailored for industrial embedded and low-power sensing designs.

Technical Context

The MAX1281BEUP+T implements a successive-approximation register (SAR) architecture with on-chip track/hold and 8-channel analog multiplexer. Its conversion timing is fully synchronous to an external serial clock (f_SCLK = 4.8MHz max), requiring 16 clock cycles per 12-bit result, with acquisition time fixed at 625ns and aperture jitter <50ps.

It supports four software-selectable power modes (normal, reduced-power, fast power-down, full power-down) and one hard-wired SHDN pin. Internal reference buffer gain is 2.05 V/V, REFADJ threshold is VDD1 − 1V, and analog input range is ±VREF/2 (bipolar) or 0 to VREF (unipolar), referenced to COM - all configurable without external components.

Key Specifications

Pinout & Package

MAX1281BEUP+T is housed in a 20-pin TSSOP package (4.4mm × 6.5mm, 0.65mm pitch) with exposed pad for thermal performance. Pin numbering follows standard top-view orientation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 12-bit SAR ADC applications.

Compared with ADS7822U and AD7490BRUZ, the MAX1281BEUP+T uniquely balances low 2.5mA active current, integrated reference, 20-pin TSSOP fit, and guaranteed ±1 LSB INL over –40°C to +85°C - making it optimal for compact, battery-sensitive, and thermally demanding measurement nodes where BOM simplicity and long-term accuracy are prioritized over raw speed or channel count.

Availability

MAX1281BEUP+T is available at Aetrix Electronics and suitable for portable data logging, medical instruments, and battery-powered instruments requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX1281BEUP+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 industrial, medical, and communications applications.

The MAX1280/MAX1281 product line delivers low-power, single-supply 12-bit SAR ADCs with integrated multiplexers and references - engineered specifically for portable, battery-constrained, and thermally rugged measurement systems where accuracy, size, and supply flexibility are critical.

FAQ

What is the maximum sampling rate of the MAX1281BEUP+T?

The MAX1281BEUP+T achieves a maximum sampling rate of 300ksps under specified conditions: VDD1 = VDD2 = +2.7V to +3.6V, fSCLK = 4.8MHz, and 16 clock cycles per conversion. This rate is guaranteed across the full –40°C to +85°C operating temperature range and supports accurate digitization of signals up to 150kHz full-linear bandwidth.

Does the MAX1281BEUP+T require an external reference voltage?

No, the MAX1281BEUP+T includes an internal +2.500V reference with ±15ppm/°C temperature coefficient and ±1.5% adjustment range via REFADJ. An external reference (1V to VDD1) may be used by disabling the internal buffer - but it is not required. The internal reference meets ±1 LSB INL specification across temperature without additional components.

How does the power-down functionality work on the MAX1281BEUP+T?

The MAX1281BEUP+T supports four power modes controlled by PD1/PD0 bits in the control byte: normal (2.5mA), reduced-power (1.3mA), fast power-down (0.9mA), and full power-down (2µA). Additionally, the SHDN pin provides hardware-initiated shutdown. Serial interface access automatically wakes the device, and turn-on time is short enough to allow power-down between consecutive conversions.

Can the MAX1281BEUP+T perform pseudo-differential measurements?

Yes, the MAX1281BEUP+T supports pseudo-differential operation on four channel pairs: CH0/CH1, CH2/CH3, CH4/CH5, and CH6/CH7. In this mode, only the positive input (IN+) is sampled; the negative input (IN−) must remain stable within ±0.5LSB relative to GND during conversion. This architecture enables differential-like rejection while retaining single-ended simplicity and lower power than true differential SAR ADCs.

What package type and RoHS status does the MAX1281BEUP+T use?

The MAX1281BEUP+T is supplied in a 20-pin TSSOP package (4.4mm × 6.5mm, 0.65mm pitch) with exposed pad for thermal dissipation. It is lead(Pb)-free and RoHS-compliant, as indicated by the "+" suffix in the part number. The device meets JEDEC J-STD-020 moisture sensitivity level 1 (MSL-1) for unlimited floor life at ≤30°C/60% RH.