Analog Devices Inc./Maxim Integrated MAX709SCUA

Overview

MAX709SCUA from Maxim Integrated is a precision power-supply monitor IC with active-low reset output, designed for +3V systems requiring reliable brownout detection and 140ms minimum power-on reset delay. It features a 2.93V nominal reset threshold, operates down to 1V supply, consumes only 35µA typical supply current, and is housed in an 8-pin µMAX package.

For engineers reviewing the MAX709SCUA datasheet, MAX709SCUA pinout, MAX709SCUA application, or MAX709SCUA equivalent, key selection criteria include reset threshold accuracy (±1.5% over temperature), immunity to short VCC transients (<40µs at 100mV overdrive), guaranteed RESET state down to VCC = 1V, and compatibility with microprocessor reset inputs requiring open-drain or push-pull drive.

Technical Context

The MAX709SCUA integrates a precision voltage reference, comparator, and timer circuit to generate a clean, glitch-immune reset signal during power-up, power-down, and brownout events. Its internal reset timeout is fixed at 140ms min after VCC rises above the 2.93V threshold, with no external components required.

It uses a bandgap-based reference and hysteresis-free comparator architecture to ensure monotonic reset assertion/deassertion. The RESET output is open-drain compatible and sinks up to 1.2mA at VCC ≥ reset threshold min, supporting direct interface to CMOS and TTL microprocessor reset inputs.

Key Specifications

Pinout & Package

MAX709SCUA is supplied in an 8-pin µMAX package (3mm × 3mm, 0.5mm pitch), with exposed pad for thermal enhancement and ground connection. Pin 1 is top-left corner (dot-marked), pin numbering follows standard counter-clockwise convention.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar power-supply monitor applications.

Compared with MAX709SCUA, MAX706S offers identical electrical behavior in a larger SO-8 package, while TPS3808G30 trades fixed timing and simplicity for ultra-low current and configurability-making MAX709SCUA optimal for cost-sensitive, space-constrained +3V systems requiring proven, no-component reset assurance.

Availability

MAX709SCUA is available at Aetrix Electronics and suitable for industrial PLC controllers, portable medical sensors, automotive body control modules, and smart energy meters requiring stable component supply and long-term lifecycle support.

Supply support for MAX709SCUA 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) is a semiconductor company specializing in analog, mixed-signal, and power-management ICs for industrial, communications, and consumer applications.

The MAX709 family was designed specifically for microprocessor supervisory functions in cost-sensitive, space-constrained embedded systems requiring precise, low-power, single-chip reset solutions across +3V, +3.3V, and +5V rails.

FAQ

What is the exact reset threshold voltage of the MAX709SCUA?

The MAX709SCUA has a nominal reset threshold voltage of 2.93V, with a guaranteed range of 2.85V (min) to 3.00V (max) over the full operating temperature range (-40°C to +85°C). This value is laser-trimmed at wafer test and specified in the Electrical Characteristics table of the official MAX709 datasheet. The 'S' suffix in MAX709SCUA explicitly denotes the 2.93V variant.

Does the MAX709SCUA require any external components to function?

No, the MAX709SCUA requires no external resistors, capacitors, or timing components to perform its core power-supply monitoring and reset generation function. A 0.1µF ceramic bypass capacitor is recommended between VCC (pin 2) and GND (pin 3) for noise immunity, but this is a standard decoupling practice-not a functional requirement for reset operation.

Can the MAX709SCUA be used with a +3.3V microprocessor supply rail?

Yes, the MAX709SCUA is fully compatible with +3.3V systems. Its 2.93V reset threshold provides appropriate margin below the +3.3V nominal rail (typically ±5%), ensuring reset assertion occurs before the µP enters undefined operation. The device operates correctly across VCC = 1.0V to 5.5V and maintains valid RESET output down to VCC = 1V.

What is the power-on reset delay time of the MAX709SCUA?

The MAX709SCUA provides a guaranteed minimum power-on reset delay of 140ms after VCC rises above the 2.93V reset threshold. This fixed timeout is internally generated and does not require external timing components. The actual delay is typically 280ms and can extend up to 560ms over temperature and process variation, ensuring robust µP initialization across all conditions.

Is the MAX709SCUA pin-compatible with other MAX709 variants like MAX709R or MAX709L?

Yes, all MAX709 variants-including MAX709SCUA, MAX709R, MAX709L, MAX709M, and MAX709T-are fully pin-compatible within the same package type (e.g., µMAX, SO, DIP). They share identical pinout, electrical interface, and timing behavior; only the reset threshold voltage differs per suffix. Therefore, MAX709SCUA can be substituted for other MAX709 variants on the same PCB without layout changes, provided the system's voltage monitoring requirement matches the 2.93V threshold.