Analog Devices Inc./Maxim Integrated MAX9120ESA

Overview

MAX9120ESA from Analog Devices is a nanopower, open-drain comparator in an 8-pin SO package, designed for ultra-low-power battery-monitoring systems. It operates down to +1.6V supply voltage, draws only 350nA supply current, features Beyond-the-Rails™ input range (VEE −0.2V to VCC +0.2V), and delivers rail-to-rail output swing with ±5mA drive capability - ideal for 2-cell battery management in portable medical instruments and telemetry systems.

For engineers reviewing the MAX9120ESA datasheet, MAX9120ESA pinout, MAX9120ESA application, or MAX9120ESA equivalent, key selection criteria include its open-drain output architecture enabling mixed-voltage logic translation, guaranteed operation at 1.6V, internal hysteresis (4mV), sub-µA quiescent current, and compatibility with ground- or supply-line sensing topologies.

Technical Context

The MAX9120ESA uses a break-before-make output stage that eliminates crowbar-current surges during switching, minimizing supply glitches and dynamic power consumption. Its input stage supports common-mode voltages beyond the rails by ±200mV and exhibits ±0.15nA typical input bias current within rail limits.

This device lacks an integrated reference (unlike MAX9117/MAX9118) and relies on external threshold setting. Its open-drain output allows pull-up to voltages up to +6V relative to VEE, supporting bidirectional logic-level translation between 3V and 5V domains without level-shifter ICs.

Key Specifications

Pinout & Package

The MAX9120ESA is housed in an 8-pin SO (Small Outline) package (S8-2 footprint), RoHS-compliant, with 1.27mm lead pitch and 3.9mm × 4.9mm body size.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLV3691IDBVR and MAX40002ANSR, the MAX9120ESA uniquely combines sub-µA current, true Beyond-the-Rails™ input, and open-drain output - making it the only choice for ground-sensing battery monitors requiring logic-level translation without added components.

Availability

MAX9120ESA is available at Aetrix Electronics and suitable for 2-cell battery monitoring, telemetry sensor interfaces, portable medical instruments, and logic-level translation applications requiring stable component supply across long production lifecycles.

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

Analog Devices is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets.

The MAX9117–MAX9120 family was engineered specifically for ultra-low-power, rail-aware sensing in battery-constrained systems - emphasizing nanopower operation, input flexibility, and robust output interfacing without external support components.

FAQ

What is the operating supply voltage range for the MAX9120ESA?

The MAX9120ESA operates from +1.6V to +5.5V. This wide low-voltage range allows direct connection to two-series alkaline, NiMH, or lithium primary cells without regulation. Operation at 1.6V is fully specified over the full −40°C to +85°C temperature range, ensuring reliability in cold-weather telemetry and portable medical devices where battery voltage sags under load.

Does the MAX9120ESA have an integrated voltage reference?

No, the MAX9120ESA does not include an internal voltage reference. Unlike the MAX9117/MAX9118 variants, it is designed for external threshold configuration. This reduces quiescent current to 350nA and avoids reference-related errors, making MAX9120ESA optimal when precise external references or resistor-divider thresholds are used - such as in battery cell voltage monitoring where accuracy depends on known divider ratios.

What is the function of pins 1, 4, 5, and 8 on the MAX9120ESA?

Pins 1, 4, 5, and 8 on the MAX9120ESA are No Connection (N.C.) terminals - they are not bonded internally and must remain unconnected on the PCB. These pins exist due to the shared 8-pin SO package footprint with other members of the MAX9117–MAX9120 family (e.g., MAX9117ESA+). Routing traces or applying solder to these pins may cause mechanical stress or unintended coupling but has no electrical effect on MAX9120ESA operation.

Can the MAX9120ESA output drive a 3V logic input when powered from a 5V supply?

Yes, the MAX9120ESA can drive a 3V logic input while powered from 5V. Its open-drain output allows the external pull-up resistor to be connected to the 3V domain. When the output transistor is off, the pull-up raises the line to 3V; when on, it pulls the line to VEE (typically ground). This provides clean, glitch-free level translation without risk of overvoltage - a key advantage confirmed in the MAX9120ESA Typical Application Circuit for logic-level translation.

What is the maximum allowable pull-up voltage on the MAX9120ESA output?

The MAX9120ESA output can be pulled up to a maximum of +6V relative to VEE. For example, if VEE = 0V (ground), the pull-up voltage may be as high as +6V; if VEE = −1V, the absolute maximum is +5V. This rating is explicitly defined in the Absolute Maximum Ratings table and enables interoperability with higher-voltage subsystems while maintaining safe operation - critical for industrial sensor nodes interfacing with 5V PLC inputs.