Analog Devices Inc./Maxim Integrated MAX9911EWT+T

Overview

The MAX9911EWT+T from Maxim Integrated is a single-channel, rail-to-rail input/output operational amplifier optimized for ultra-low-power, precision battery-powered systems. It delivers 200kHz gain-bandwidth, 4µA supply current (typ), 1pA input bias current (typ), and operates from 1.8V to 5.5V - enabling use in portable medical sensors and glucose meters where microamp-level quiescent current and high-impedance signal conditioning are critical.

For engineers reviewing the MAX9911EWT+T datasheet, MAX9911EWT+T pinout, MAX9911EWT+T application, or MAX9911EWT+T equivalent, this page provides verified technical context, package-specific pin mapping, real-world application cards, and two validated alternative op amps with documented functional and interface differences.

Technical Context

The MAX9911EWT+T uses a CMOS input stage with parallel n- and p-channel transistors to achieve rail-to-rail input common-mode range extending 100mV beyond both supply rails and output swing within 5mV of rails under 100kΩ load. Its unity-gain stability supports capacitive loads up to 30pF directly, or up to 250pF at ≥10V/V gain.

It features an active-low shutdown pin (SHDN) that reduces supply current to 1nA (typ) and places the output in high-impedance state within 2µs (typ). Input offset voltage is ±200µV (typ), with ±5mV max over –40°C to +85°C, and PSRR reaches 95dB (typ) at 5.5V supply - enabling direct battery connection without regulation.

Key Specifications

Pinout & Package

The MAX9911EWT+T is housed in a 6-bump Wafer-Level Package (WLP), bottom-side marked "BQ", with 0.5mm pitch and 1.27mm × 0.87mm footprint. This ultra-compact package targets space-constrained PCBs in disposable or miniaturized medical sensors.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar precision low-power op amp applications.

Compared with MAX4477ASA+T and LTC2050CS5#TRMPBF, the MAX9911EWT+T uniquely combines shutdown capability, true rail-to-rail output, and sub-5µA supply current in a WLP - making it the only option for miniaturized, battery-limited medical sensors requiring both precision and aggressive power cycling.

Availability

The MAX9911EWT+T is available at Aetrix Electronics and suitable for portable medical devices, glucose meters, and handheld test equipment requiring stable component supply across long production lifecycles and temperature extremes.

Supply support for MAX9911EWT+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 MAX9910–MAX9913 family was engineered specifically for ultra-low-power, rail-to-rail signal conditioning in battery-operated medical and portable instrumentation - prioritizing microamp quiescent current, femtoamp input bias, and robust single-supply operation.

FAQ

What is the maximum capacitive load the MAX9911EWT+T can drive without external compensation?

The MAX9911EWT+T is unity-gain stable with capacitive loads up to 30pF when configured as a buffer (AV = 1V/V). For larger loads, an isolation resistor (RISO) is required - e.g., 6.2kΩ for 100pF - to prevent peaking or oscillation. At gains ≥10V/V, it supports up to 250pF directly. This behavior is confirmed in the Typical Operating Characteristics section of the MAX9911EWT+T datasheet, Figure toc15 and toc16.

Does the MAX9911EWT+T support true rail-to-rail output swing at 1.8V supply?

Yes. The MAX9911EWT+T achieves rail-to-rail output swing within 5mV of both VDD and VSS when loaded with 100kΩ, even at 1.8V supply. At 5kΩ load, output swing is within 60mV of the rails. This performance is specified in the Electrical Characteristics table under VOH and VOL parameters and validated across the full –40°C to +85°C range - critical for maximizing dynamic range in low-voltage portable medical devices using the MAX9911EWT+T.

How does the shutdown function affect the output state of the MAX9911EWT+T?

When SHDN is driven low, the MAX9911EWT+T enters shutdown mode, reducing supply current to 1nA (typ) and placing the output terminal in a high-impedance (Hi-Z) state - effectively disconnecting it from the downstream circuit. This prevents loading or back-driving of connected nodes (e.g., ADC inputs or filters). The output returns to active operation within 30µs (typ) after SHDN is pulled high. This behavior is explicitly defined in the Shutdown Mode section of the MAX9911EWT+T datasheet.

What is the input common-mode voltage range specification for the MAX9911EWT+T?

The MAX9911EWT+T features a rail-to-rail input stage with a common-mode voltage range of VSS – 0.1V to VDD + 0.1V at 25°C, guaranteed by CMRR testing. Over temperature (–40°C to +85°C), this tightens slightly to VSS – 0.05V to VDD + 0.05V. This extended range allows the device to accurately amplify signals that exceed the supply rails - essential for interfacing with biased electrochemical sensors or mismatched signal sources in portable medical equipment using the MAX9911EWT+T.

Is the MAX9911EWT+T RoHS-compliant and lead-free?

Yes. The "+T" suffix in MAX9911EWT+T indicates a lead(Pb)-free and RoHS-compliant package, per Maxim Integrated's ordering information table and Package Information section. The WLP package uses matte tin finish and complies with JEDEC J-STD-020 reflow profiles, with peak soldering temperature rated at +260°C for lead-free processes - confirmed in the Absolute Maximum Ratings table of the MAX9911EWT+T datasheet.