Analog Devices Inc./Maxim Integrated MAX709TESA+

Overview

MAX709TESA+ from Maxim Integrated is a precision power-supply monitor IC with reset functionality for +3V systems, featuring a 3.08V nominal reset threshold, 140ms minimum power-on reset delay, guaranteed RESET assertion down to VCC = 1V, and low 35µA supply current. It serves as a system supervisory device in microprocessor-based embedded controllers requiring reliable brownout detection and clean power-up sequencing.

For engineers reviewing the MAX709TESA+ datasheet, MAX709TESA+ pinout, MAX709TESA+ application, or MAX709TESA+ equivalent, key selection criteria include reset threshold accuracy (±1.5% over temperature), immunity to short negative VCC transients (<40µs at 100mV overdrive), SO-8 package compatibility, and support for 0°C to +70°C or –40°C to +85°C operation depending on suffix.

Technical Context

The MAX709TESA+ integrates a precision voltage comparator with hysteresis and an internal timer to generate a monotonic, glitch-free active-low RESET signal. Its reset threshold is factory-trimmed to 3.08V ±1.5%, stable over –40°C to +85°C, and independent of supply rate-of-rise (up to 100V/µs).

It operates across a 1.0V–5.5V VCC range, sinks up to 1.2mA at RESET while maintaining <0.4V output voltage, and remains functional with VCC as low as 1V-ensuring deterministic reset behavior during deep brownout conditions before full system collapse.

Key Specifications

Pinout & Package

MAX709TESA+ is housed in an 8-pin SO (Small Outline) package per JEDEC MS-012, with 1.27mm lead pitch, gull-wing leads, and exposed pad not connected internally. Pin 1 is top-left corner (marking dot adjacent), pin numbering counterclockwise.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX706TESA+, MAX709TESA+ omits watchdog and manual reset but delivers identical reset timing and threshold accuracy in the same SO-8 footprint-reducing cost and complexity where those features are unused. Against TPS3808G30DBVR, MAX709TESA+ provides higher RESET sink current (1.2mA vs. 20mA max) and proven industrial temperature resilience, at the expense of higher quiescent current and larger package.

Availability

MAX709TESA+ is available at Aetrix Electronics and suitable for industrial control systems, medical handheld diagnostics, automotive body electronics, and smart utility metering requiring stable component supply and long-term lifecycle support.

Supply support for MAX709TESA+ 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, communications, and computing markets.

The MAX709 belongs to Maxim's µP Supervisory Circuits product line, designed specifically to replace discrete reset solutions in cost-sensitive, space-constrained microprocessor systems requiring reliable power-on, power-down, and brownout reset generation.

FAQ

What is the exact reset threshold voltage of the MAX709TESA+?

The MAX709TESA+ has a factory-trimmed nominal reset threshold voltage of 3.08V, with a tolerance of ±1.5% over the full operating temperature range (–40°C to +85°C). This value is specified in the Electrical Characteristics table under "RESET Threshold, VTH" for suffix 'T', and confirmed in the Ordering Information section of the official Maxim datasheet. The MAX709TESA+ is explicitly designated for +3V system supervision.

Does the MAX709TESA+ require external components to function?

No, the MAX709TESA+ requires no external components to perform its core power-supply monitoring and reset function. It integrates a precision voltage reference, comparator, and timing circuit on-die. A 0.1µF ceramic bypass capacitor on VCC (pin 2) is strongly recommended for noise immunity but is not strictly required for basic operation. No resistors, capacitors, or diodes are needed for threshold setting or delay timing.

What is the guaranteed minimum reset pulse width for the MAX709TESA+?

The MAX709TESA+ guarantees a minimum reset active timeout period of 140ms after VCC rises above the reset threshold. This is specified in the Electrical Characteristics table under "Reset Active Timeout Period" and applies across the full temperature range. The typical value is 280ms, and maximum is 560ms, but design-critical timing must be based on the 140ms minimum to ensure µP initialization completes reliably.

Can the MAX709TESA+ operate with VCC below 3V?

Yes, the MAX709TESA+ operates with VCC as low as 1.0V, and its RESET output is guaranteed to remain correctly asserted (low) down to VCC = 1V. Below 1V, RESET becomes high-impedance (open-circuit), so a pull-down resistor is recommended if valid logic state must be maintained all the way to 0V. This capability allows the MAX709TESA+ to supervise deeply undervolted rails and provide fail-safe reset during severe brownouts.

Is the MAX709TESA+ pin-compatible with other MAX709 variants like MAX709ESA+?

Yes, all MAX709 variants-including MAX709TESA+, MAX709ESA+, and MAX709CSA+-share identical pinout, package (SO-8), and terminal functions. The suffix denotes only temperature grade (E = –40°C to +85°C, C = 0°C to +70°C) and reset threshold (T = 3.08V, S = 2.93V, R = 2.63V, etc.). Therefore, MAX709TESA+ is a direct replacement for any other MAX709xSA+ variant in the same package, provided the 3.08V threshold meets system requirements.