Analog Devices Inc./Maxim Integrated MAX9120ESA+

Overview

MAX9120ESA+ from Maxim Integrated is an open-drain nanopower comparator without internal reference, designed for ultra-low-power battery monitoring and mixed-voltage interface applications. It operates from +1.6V to +5.5V, draws only 350nA supply current at 25°C, features Beyond-the-Rails™ inputs extending 200mV beyond VEE and VCC, and delivers rail-to-rail output swing with ±5mA sink capability - enabling direct use in 2-cell Li-ion or alkaline systems.

For engineers reviewing the MAX9120ESA+ datasheet, MAX9120ESA+ pinout, MAX9120ESA+ application, or MAX9120ESA+ equivalent, key selection criteria include its open-drain output architecture for level translation, guaranteed sub-2µs propagation delay at 100mV overdrive, input offset voltage ≤10mV over temperature, and SC70-5 package compatibility with space-constrained portable designs.

Technical Context

The MAX9120ESA+ implements a break-before-make output stage that eliminates crowbar current during switching, minimizing supply glitches and dynamic power surges. Its input stage supports common-mode voltages from VEE −0.2V to VCC +0.2V and includes internal hysteresis (4mV) to prevent oscillation on slow or noisy signals.

Unlike push-pull comparators, the open-drain output allows pull-up to a voltage rail independent of VCC - up to +6V referenced to VEE - making it suitable for bidirectional logic-level translation (e.g., 5V-to-3V or 3V-to-5V) and wire-OR bus configurations without external level shifters.

Key Specifications

Pinout & Package

MAX9120ESA+ is housed in an 8-pin SO (SOIC-N) package with lead-free finish (+ suffix). Pin 1 is marked by a beveled corner or dot; pin numbering follows standard SOIC convention (counterclockwise from pin 1).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar nanopower open-drain comparator applications.

Compared with TLV3691IDBVR and MAX40006ETA+, the MAX9120ESA+ uniquely combines open-drain output, Beyond-the-Rails™ input range, and internal hysteresis at 350nA - making it optimal for battery-monitoring and ground-referenced sensing where layout simplicity and rail flexibility are critical.

Availability

MAX9120ESA+ is available at Aetrix Electronics and suitable for 2-cell battery monitoring, ultra-low-power telemetry, and logic-level translation requiring stable component supply across industrial, medical, and portable electronics programs.

Supply support for MAX9120ESA+ 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, automotive, and communications applications.

The MAX9117–MAX9120 family was engineered specifically for nanopower, rail-flexible threshold detection in battery-constrained systems - emphasizing supply current minimization, input range extension, and glitch-free switching behavior.

FAQ

What is the maximum allowable voltage on the MAX9120ESA+ output pin?

The MAX9120ESA+ output pin (pin 1) is open-drain and rated for voltages up to +6V referenced to VEE (GND). This allows safe pull-up to higher rails such as 5V while VCC = 3.3V - a key enabler for bidirectional logic-level translation. Exceeding +6V relative to VEE risks permanent damage per Absolute Maximum Ratings.

Does the MAX9120ESA+ require an external reference for basic comparator operation?

No. The MAX9120ESA+ does not include an internal reference - unlike the MAX9117/MAX9118 variants. It functions as a standalone comparator requiring an external reference or threshold voltage applied to IN− or IN+. This simplifies design when a system already provides a stable reference or uses resistor-divider thresholds.

Can the MAX9120ESA+ operate from a single 1.6V supply?

Yes. The MAX9120ESA+ is fully specified down to +1.6V supply voltage, with functional operation confirmed across −40°C to +85°C. At 1.6V, supply current remains ≤1.2µA, propagation delay increases modestly (tPD− = 16µs), and output swing maintains rail-to-rail capability with ≥100mV margin - validated in Electrical Characteristics tables.

How does the MAX9120ESA+ handle input overvoltage conditions beyond the supply rails?

The MAX9120ESA+ input stage includes ESD protection diodes to VCC and VEE. When input voltage exceeds VCC +0.3V or falls below VEE −0.3V, these diodes conduct - limiting fault current to ±20mA per Absolute Maximum Ratings. For sustained overvoltage, external series resistors are recommended to keep current within safe limits.

Is the MAX9120ESA+ pin-compatible with other devices in the MAX9117–MAX9120 family?

No. The MAX9120ESA+ uses an 8-pin SO package, while the SC70-5 variants (e.g., MAX9120EXK-T) use a 5-pin footprint. Even within SO packages, pinouts differ: MAX9120ESA+ has N.C. on pins 4, 6, and 8, whereas MAX9117ESA+ routes REF to pin 4. Direct PCB replacement requires layout revision.