Analog Devices Inc./Maxim Integrated MAX709MCSA+T

Overview

MAX709MCSA+T from Maxim Integrated is a precision power-supply monitor IC with active-low reset output, designed for +3.3V and +5V microprocessor systems. It asserts RESET when VCC falls below 4.40V (±2.5%), holds reset for ≥140ms after VCC recovers, operates down to VCC = 1V, and draws only 65µA typical supply current. Used in embedded controllers requiring reliable brownout detection and power-on sequencing.

For engineers reviewing the MAX709MCSA+T datasheet, MAX709MCSA+T pinout, MAX709MCSA+T application, or MAX709MCSA+T equivalent, key selection criteria include reset threshold accuracy (4.40V), guaranteed reset hold time (140ms min), low quiescent current (65µA), immunity to short VCC transients (<40µs at 100mV overdrive), and compatibility with SO-8 packaging for surface-mount production.

Technical Context

The MAX709MCSA+T integrates a precision voltage comparator, internal timing capacitor, and open-drain reset driver in a single SO-8 package. Its reset threshold is factory-trimmed to 4.40V with ±2.5% tolerance over –40°C to +85°C, and its 140ms reset timeout is temperature-stable across the full operating range.

It requires no external components for basic operation, supports bidirectional µP reset pins via series resistor interface, and maintains valid RESET state down to VCC = 1V - enabling robust reset assertion during deep brownout conditions without external pull-downs in most applications.

Key Specifications

Pinout & Package

MAX709MCSA+T is housed in an 8-pin SO (Small Outline) package, 150mil width, RoHS-compliant and lead-free (+T suffix). Pin 1 is top-left corner (notch-marked), with standard SO-8 pin numbering.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX706MESA+, MAX709MCSA+T provides identical reset accuracy and timing but omits manual reset and watchdog features - reducing cost and board space where those functions are unused. Versus TPS3808G33DBVR, MAX709MCSA+T delivers tighter threshold alignment for +5V systems and broader V_CC operating range (1.0V–5.5V vs. 0.8V–6.0V), though at higher quiescent current.

Availability

MAX709MCSA+T is available at Aetrix Electronics and suitable for industrial control systems, medical handheld devices, automotive body electronics, and smart energy meters requiring stable component supply and long-term lifecycle support.

Supply support for MAX709MCSA+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) is a fabless semiconductor company specializing in high-performance analog, mixed-signal, and power-management ICs for industrial, automotive, and communications markets.

The MAX709 family was designed specifically for cost-sensitive, high-reliability microprocessor supervisory applications - delivering precision reset thresholds, guaranteed timeout periods, and minimal external component count in compact packages.

FAQ

What is the exact reset threshold voltage for MAX709MCSA+T?

The MAX709MCSA+T has a nominal reset threshold voltage of 4.40V, with a guaranteed tolerance of ±2.5% over the full operating temperature range (–40°C to +85°C). This value is factory-trimmed and specified in the Electrical Characteristics table under "RESET Threshold, VTH" for suffix M. The device asserts RESET when VCC falls below this threshold and holds it active until VCC rises above the threshold and remains stable for ≥140ms.

Does MAX709MCSA+T require external components to function?

No, MAX709MCSA+T operates fully autonomously with no external components required for basic reset functionality. A 0.1µF ceramic bypass capacitor is recommended between VCC (pin 2) and GND (pin 3) to improve transient immunity, but it is not mandatory for DC operation. No resistors, capacitors, or trimming elements are needed to set threshold or timeout - both are internally fixed and calibrated.

What is the supply current consumption of MAX709MCSA+T?

The MAX709MCSA+T draws 65µA typical supply current (I_CC) at VCC = 5.5V and TA = +25°C, with a maximum of 200µA across the full temperature and voltage range. This value applies specifically to the L/M versions (including MAX709MCSA+T); R/S/T variants consume 35µA typical. The current remains stable regardless of RESET output state, enabling predictable power budgeting in low-power designs.

Can MAX709MCSA+T be used with microprocessors that have bidirectional reset pins?

Yes, MAX709MCSA+T can interface with bidirectional reset pins (e.g., Motorola 68HC11) using a 4.7kΩ series resistor between the MAX709MCSA+T RESET output and the µP reset I/O. This prevents contention when the µP attempts to drive the line while MAX709MCSA+T is asserting reset. The resistor value is noncritical but must be large enough to limit current yet small enough to avoid signal degradation - 4.7kΩ is the manufacturer-recommended value per Application Information section.

What package type and dimensions does MAX709MCSA+T use?

MAX709MCSA+T uses an 8-pin SO (Small Outline) package, 150mil body width, with lead pitch of 1.27mm (0.050"). Dimensions are 4.90mm × 3.91mm × 1.45mm (L × W × H), compliant with JEDEC MS-012. The "+T" suffix denotes lead-free, RoHS-compliant construction. Pin 1 is located at the top-left corner adjacent to the package notch, and all N.C. pins (1,4,5,6,8) must remain unconnected or tied to GND per layout guidelines.