Analog Devices Inc./Maxim Integrated MAX709MESA

Overview

MAX709MESA from Maxim Integrated is a precision power-supply monitor IC with active-low reset output, designed for +3.3V and +5V systems. It asserts RESET when VCC falls below 4.40V (±0.15V), holds reset for ≥140ms after VCC recovers, operates down to 1V supply, consumes only 65µA, and is housed in an 8-pin SO package. It ensures reliable microprocessor reset during power-up, brownout, and power-down events in embedded controllers.

For engineers reviewing the MAX709MESA datasheet, MAX709MESA pinout, MAX709MESA application, or MAX709MESA equivalent, key selection criteria include reset threshold accuracy (4.40V), guaranteed reset assertion at VCC ≥1V, 140ms minimum reset timeout, immunity to short negative VCC transients (<40µs at 100mV overdrive), and compatibility with 3.3V/5V logic interfaces.

Technical Context

The MAX709MESA integrates a precision voltage comparator with hysteresis and a monostable timer to generate a clean, glitch-immune reset pulse. Its internal reference is trimmed to ±1.5% over temperature, enabling stable operation across –40°C to +85°C without external components.

It features open-drain RESET output with guaranteed sink capability (1.2mA at VTH min) and source capability (500µA), supports bidirectional µP reset pins via series resistor buffering, and maintains valid logic state down to VCC = 1V - critical for low-voltage system sequencing and fail-safe shutdown.

Key Specifications

Pinout & Package

MAX709MESA is supplied in an 8-pin SO (Small Outline) package, 150mil width, with gull-wing leads and RoHS-compliant lead-free finish.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX706MESA and TPS3808G33DBVR, the MAX709MESA delivers optimal balance of industrial temperature support (–40°C to +85°C), proven noise immunity, and minimal external component count for cost-sensitive 3.3V/5V microcontroller reset supervision - without requiring manual reset or ultra-low-I_Q optimization.

Availability

MAX709MESA is available at Aetrix Electronics and suitable for industrial PLC controllers, medical diagnostic devices, automotive body control modules, and IoT edge sensor nodes requiring stable component supply and long-term lifecycle support.

Supply support for MAX709MESA 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 U.S.-based semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for industrial, automotive, and communications markets.

The MAX709 family was engineered specifically for robust, low-cost microprocessor reset supervision in harsh environments - delivering precision threshold detection, glitch immunity, and wide supply voltage operation without external trimming components.

FAQ

What is the exact reset threshold voltage of the MAX709MESA?

The MAX709MESA has a nominal reset threshold voltage of 4.40V, with a guaranteed range of 4.25V to 4.50V over the full operating temperature range (–40°C to +85°C). This threshold is factory-trimmed and specified in the Electrical Characteristics table of the official MAX709 datasheet. The 'M' suffix in MAX709MESA explicitly denotes the 4.40V version, distinguishing it from other variants like MAX709L (4.65V) or MAX709R (2.63V).

Does the MAX709MESA require external components to operate?

No, the MAX709MESA requires no external resistors, capacitors, or trimming components to perform its core reset supervision function. A 0.1µF ceramic bypass capacitor placed close to the VCC pin is recommended for transient immunity but is not strictly required for basic operation. The device integrates a precision voltage reference, comparator, and timing circuit - making it a true single-chip solution for power-on and brownout reset generation in MAX709MESA-based designs.

Can the MAX709MESA drive a standard microprocessor reset input directly?

Yes, the MAX709MESA can drive most standard microprocessor reset inputs directly. Its open-drain RESET output sinks up to 1.2mA at the minimum reset threshold voltage, which exceeds the typical 100µA–500µA input leakage requirements of CMOS/TTL reset pins. An external pull-up resistor (typically 10kΩ to VCC) is required to establish the high-impedance idle state. For µPs with bidirectional reset I/O (e.g., Motorola 68HC11), a 4.7kΩ series resistor between MAX709MESA and the µP is recommended to prevent contention.

What is the minimum supply voltage at which the MAX709MESA guarantees correct RESET output state?

The MAX709MESA guarantees correct RESET output state down to VCC = 1.0V. Below this voltage, the RESET output transitions to a high-impedance (open-circuit) state rather than an undefined level - a design feature that prevents erroneous logic states during deep brownout. This behavior is explicitly characterized in the Absolute Maximum Ratings and Electrical Characteristics sections of the MAX709 datasheet and applies to all versions including MAX709MESA.

Is the MAX709MESA pin-compatible with other members of the MAX709 family?

Yes, all MAX709 variants - including MAX709MESA, MAX709LESA, MAX709TESA, and MAX709RESA - share identical 8-pin SO package footprints and pinouts. The only differences are reset threshold voltage and temperature grade; electrical interface, timing, and DC characteristics (except threshold and supply current) are fully compatible. This allows direct substitution within the same package type without PCB changes, provided the application's voltage monitoring requirement matches the selected suffix.