Analog Devices Inc./Maxim Integrated MAX11205BEUB+T

Overview

MAX11205BEUB+T from Maxim Integrated is a 16-bit, single-channel, ultra-low-power delta-sigma ADC optimized for high-dynamic-range sensor measurement in 4–20mA industrial loops. It delivers 720nV_RMS noise, 3ppm INL, and 13.75sps output rate with internal 2.2528MHz oscillator - all in a 10-pin µMAX (FMAX) package operating from -40°C to +85°C.

For engineers reviewing the MAX11205BEUB+T datasheet, MAX11205BEUB+T pinout, MAX11205BEUB+T application, or MAX11205BEUB+T equivalent, key selection considerations include its 2-wire serial interface timing, differential analog/reference inputs, on-demand self-calibration, sleep-mode current <0.1µA, and 50/60Hz line-noise rejection exceeding 144dB.

Technical Context

The MAX11205BEUB+T implements a third-order delta-sigma modulator followed by an on-chip SINC4 digital filter, enabling 16-bit noise-free resolution at 13.75sps. Its fully differential analog input (AINP/AINN) and reference inputs (REFP/REFN) support bipolar ±V_REF operation with common-mode range from GND to AVDD.

Internal clock generation eliminates external crystal requirements; the 2.2528MHz oscillator is trimmed for stability across temperature and supply voltage. The 2-wire interface uses only SCLK and RDY/DOUT pins, with data readout triggered by falling-edge detection and MSB-first two's complement format.

Key Specifications

Pinout & Package

Package: 10-pin µMAX (FMAX), RoHS-compliant, lead(Pb)-free, dimensions 3.0mm × 3.0mm × 0.8mm.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar delta-sigma ADC applications.

Compared with ADS1118IRUGT and AD7792BRUZ, the MAX11205BEUB+T uniquely balances ultra-low sleep current (<0.1µA), 2-wire simplicity, and 144dB line-noise rejection - making it optimal for space- and power-constrained single-sensor nodes where minimal external components are critical.

Availability

MAX11205BEUB+T is available at Aetrix Electronics and suitable for industrial sensor interfaces, loop-powered transmitters, and portable instrumentation requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MAX11205BEUB+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 MAX11205BEUB+T belongs to Maxim's ultra-low-power delta-sigma ADC family, engineered specifically for high-accuracy, low-power sensor digitization in harsh industrial environments and battery-operated equipment.

FAQ

What is the maximum sampling rate of the MAX11205BEUB+T?

The MAX11205BEUB+T operates at a fixed output data rate of 13.75 samples per second (sps), as defined by its B-grade variant designation. This rate is internally set and not user-programmable; it corresponds to the 2.2528MHz internal oscillator frequency and SINC4 filter configuration optimized for high line-noise rejection and low power.

Does the MAX11205BEUB+T require external passive components for basic operation?

No, the MAX11205BEUB+T requires no external passive components for core operation: its 2.2528MHz internal oscillator eliminates the need for crystals or resonators, and the 2-wire interface needs only pull-up resistors on RDY/DOUT if open-drain behavior is used. However, 0.1µF bypass capacitors on AVDD and DVDD are mandatory for specified PSRR and noise performance.

How does the MAX11205BEUB+T achieve 144dB 50/60Hz rejection?

The MAX11205BEUB+T achieves 144dB 50/60Hz rejection through synchronized sampling and a SINC4 digital filter whose notch frequency is precisely aligned to line frequencies when operating at its native 13.75sps output rate. This architecture rejects both common-mode and normal-mode interference without external hardware, as confirmed in the device's electrical characteristics table under NMR50/NMR60.

Can the MAX11205BEUB+T interface directly with a 1.8V microcontroller?

Yes, the MAX11205BEUB+T supports independent digital supply (DVDD) from 1.7V to 3.6V, allowing direct connection to 1.8V logic. Its SCLK input thresholds (V_IL = 0.3×VDVDD, V_IH = 0.7×VDVDD) and RDY/DOUT output levels (V_OH = 0.9×VDVDD) ensure reliable 1.8V-compatible signaling without level shifters.

What is the purpose of the 25th and 26th SCLK pulses in the MAX11205BEUB+T interface?

The 25th SCLK pulse pulls the RDY/DOUT pin back to its idle high state after reading 16 bits of conversion data. The 26th SCLK pulse initiates an on-demand offset and gain self-calibration cycle - a feature unique to the MAX11205BEUB+T that corrects for thermal drift and supply variations without host processor involvement.