Analog Devices Inc./Maxim Integrated MAX1081BCUP+

Overview

MAX1081BCUP+ from Maxim Integrated is a 10-bit, 300ksps serial analog-to-digital converter with integrated 8-channel multiplexer, track/hold, and internal +2.5V reference. It operates from a single +2.7V to +3.6V supply, supports software-configurable unipolar/bipolar and single-ended/pseudo-differential inputs, and delivers ±0.5 LSB INL and 60dB SINAD in battery-powered data acquisition systems.

For engineers reviewing the MAX1081BCUP+ datasheet, MAX1081BCUP+ pinout, MAX1081BCUP+ application, or MAX1081BCUP+ equivalent, key selection criteria include its 300ksps sampling rate at 2.5mA supply current, TSSOP-20 package compatibility with space-constrained portable instruments, and SPI/QSPI/MICROWIRE interface readiness for microcontroller integration without level-shifting logic.

Technical Context

The MAX1081BCUP+ employs successive-approximation register (SAR) architecture with an on-chip track/hold circuit that acquires input signals in ≤625ns. Its pseudo-differential input structure allows four differential channel pairs (CH0/CH1 through CH6/CH7), while maintaining single-ended operation via COM reference-both modes configurable via 8-bit control word.

It features four programmable power modes (normal, REDP, FASTPD, FULLPD), enabling dynamic current scaling from 2.5mA down to 2µA. The internal reference buffer provides ±1.5% adjustment range via REFADJ, and supports external reference input from 1.0V to VDD1 when disabled.

Key Specifications

Pinout & Package

The MAX1081BCUP+ is housed in a 20-pin Thin Shrink Small Outline Package (TSSOP) with 0.65mm pitch, 6.5mm × 4.4mm body, and exposed pad for thermal enhancement. Pin 1 is marked by a dot; pin numbering follows standard counter-clockwise orientation from top-left corner.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADS7822U and AD7490BRUZ, the MAX1081BCUP+ offers optimal balance of integrated functionality (reference, power modes, pseudo-differential support), compact TSSOP-20 packaging, and 300ksps throughput at 2.5mA-making it ideal for cost- and size-constrained portable instrumentation where 10-bit resolution meets system requirements.

Availability

MAX1081BCUP+ is available at Aetrix Electronics and suitable for portable data logging, battery-powered instruments, and medical devices requiring stable component supply with guaranteed long-term availability and traceable sourcing.

Supply support for MAX1081BCUP+ 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 MAX1080/MAX1081 product line targets low-power, multi-channel data acquisition in space- and energy-constrained systems-emphasizing integrated signal conditioning, flexible interface compatibility, and robust performance across temperature.

FAQ

What is the maximum sampling rate of the MAX1081BCUP+ and what clock frequency is required?

The MAX1081BCUP+ achieves a maximum sampling rate of 300ksps, which requires a serial clock (SCLK) frequency of 4.8MHz with 50% duty cycle. Each conversion consumes 16 clock cycles, so the SCLK period directly determines throughput. Operating below 4.8MHz reduces sampling rate proportionally, enabling flexible trade-offs between speed and power consumption in the REDP and power-down modes.

Does the MAX1081BCUP+ support true differential input operation?

No, the MAX1081BCUP+ implements pseudo-differential input architecture: only the positive input (IN+) is actively sampled by the track/hold circuit, while the negative input (IN−) remains static during conversion. In pseudo-differential mode, IN− is selected from paired channels (e.g., CH0/CH1), but it must remain stable within ±0.5 LSB relative to GND to avoid conversion error-unlike true differential ADCs that sample both inputs simultaneously.

How does the internal reference of the MAX1081BCUP+ behave under varying supply voltage?

The internal reference of the MAX1081BCUP+ maintains a nominal 2.500V output with ±15ppm/°C temperature coefficient and ±0.5mV variation over the +2.7V to +3.6V supply range, as confirmed by Figure MAX1080/1-09 in the datasheet. This stability eliminates supply-rail tracking errors in ratiometric sensor measurements and ensures consistent full-scale definition independent of VDD fluctuations.

Can the MAX1081BCUP+ operate with an external reference, and how is it configured?

Yes, the MAX1081BCUP+ supports external reference voltages from 1.0V to VDD1. To enable this mode, connect REFADJ to VDD1 to disable the internal reference buffer, then apply the external reference to the REF pin. The device retains full functionality-including unipolar/bipolar configuration and power modes-but relies on external reference accuracy and noise performance for overall system precision.

What are the thermal considerations for the MAX1081BCUP+ in continuous operation?

The MAX1081BCUP+ in TSSOP-20 has a junction-to-ambient thermal resistance (θ_JA) of 120°C/W. At 2.5mA supply current and 3.3V supply, power dissipation is ~8.25mW, resulting in <1°C junction rise above ambient-well within the −40°C to +85°C operating range. No heatsinking is required, but layout best practices (solid ground plane, thermal vias under exposed pad) ensure reliability in sealed enclosures.