Analog Devices Inc./Maxim Integrated MAX806TMJA

Overview

MAX806TMJA from Maxim Integrated is a precision 3.3V/3.0V microprocessor supervisory circuit with active-high open-drain RESET output, 3.075V reset threshold (T-suffix), -55°C to +125°C military-grade CERDIP package, 200ms reset timeout, and integrated watchdog timer (1.6s timeout). It monitors VCC, provides battery switchover (VBATT > VCC supported), power-fail warning (PFI/PFO), and manual reset - used in ruggedized embedded controllers and aerospace-grade battery-backed RAM systems.

For engineers reviewing the MAX806TMJA datasheet, MAX806TMJA pinout, MAX806TMJA application, or MAX806TMJA equivalent, key selection criteria include guaranteed RESET assertion down to VCC = 1V, ±2% reset threshold accuracy, 40µA VCC supply current, battery leakage <5µA, and CERDIP packaging for extended temperature operation in mission-critical environments.

Technical Context

The MAX806TMJA implements a dual-threshold reset comparator with 10mV typical hysteresis, ensuring stable reset assertion during VCC brownouts without oscillation. Its internal PMOS VCC-to-VOUT switch (3Ω typical on-resistance) and NMOS VBATT-to-VOUT switch (140Ω typical) enable seamless, low-dropout backup power switchover at VSW = 2.40V (VBATT > VCC).

It integrates a non-disableable watchdog timer cleared only by WDI edges or RESET assertion, with 1.6s timeout tolerance of ±40%. The PFI input features 1.237V threshold with ±20mV hysteresis and sub-500nA input current over full temperature range, supporting precise external supply monitoring.

Key Specifications

Pinout & Package

MAX806TMJA is housed in an 8-pin CERDIP (Ceramic Dual In-line Package) with hermetic sealing and gold-plated leads, rated for high-reliability, extended-temperature operation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar microprocessor supervisory applications.

Compared with MAX806TEPA and MAX806TESA, the MAX806TMJA uniquely delivers hermetic CERDIP packaging and -55°C to +125°C qualification - essential for systems where moisture ingress, thermal shock, or extended temperature operation invalidates plastic or SOIC alternatives.

Availability

MAX806TMJA is available at Aetrix Electronics and suitable for avionics data recorders, downhole oilfield sensors, ruggedized industrial PLCs, and military handheld radios requiring stable component supply under extended temperature and high-reliability constraints.

Supply support for MAX806TMJA 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) designs precision analog and mixed-signal ICs for demanding industrial, automotive, and communications applications.

The MAX806TMJA belongs to Maxim's high-reliability microprocessor supervisory family, engineered specifically for mission-critical systems requiring guaranteed reset behavior, battery-backed memory retention, and operation across extreme temperature ranges.

FAQ

What is the reset threshold voltage of the MAX806TMJA and how tightly is it specified?

The MAX806TMJA has a nominal reset threshold of 3.075V, with a tolerance of ±2% over the full -55°C to +125°C temperature range. This tight specification ensures consistent brownout detection across extreme environments, and is tighter than the ±4% found in earlier MAX690-series devices. The threshold applies to both rising and falling VCC transitions, with built-in hysteresis preventing chatter near the trip point. This value is confirmed in the Electrical Characteristics table of the official Maxim datasheet for MAX806TMJA.

Does the MAX806TMJA support battery voltages higher than VCC, and what is the maximum allowed VBATT?

Yes, the MAX806TMJA explicitly supports VBATT exceeding VCC - a key feature enabling direct connection of standard 3.6V lithium batteries without diodes or regulators. The absolute maximum rating for VBATT is +6.0V, and the internal switchover circuit activates when VCC falls below 2.40V (VSW) while VBATT remains higher. This capability is validated in the "Battery-Backup Power Switching" section and Absolute Maximum Ratings table of the MAX806TMJA datasheet.

What is the function of the RESET pin on the MAX806TMJA, and how does it differ from the RESET pin on other MAX80x devices?

The RESET pin on the MAX806TMJA is an active-high, open-drain output - the logical inverse of the active-low RESET found on MAX690/MAX704 devices. It requires an external pull-up resistor to VCC and is designed to interface directly with µPs that accept active-high reset signals. This distinction is clearly documented in the Pin Description table and Block Diagram of the MAX806TMJA datasheet, and differentiates it from the MAX802/MAX804 families which use active-low outputs.

Can the watchdog timer on the MAX806TMJA be disabled, and what triggers its timeout?

No, the watchdog timer on the MAX806TMJA cannot be disabled - it is always active per the datasheet. Timeout occurs if the WDI pin remains static (high or low) for 1.6 seconds (1.12–2.24s over temperature). The timer resets on any edge (rising or falling) at WDI, or while RESET is asserted. This behavior is confirmed in the "Watchdog Input" section and Electrical Characteristics table, and distinguishes MAX806TMJA from older MAX690 variants where watchdog disable was possible.

What package type and temperature grade does the MAX806TMJA use, and why is this significant for design?

The MAX806TMJA uses an 8-pin CERDIP (ceramic dual in-line) package rated for -55°C to +125°C operation. This hermetic, military-grade construction provides superior moisture resistance, thermal cycling endurance, and long-term reliability compared to plastic DIP or SOIC packages. It is essential for applications in aerospace, defense, and oilfield electronics where environmental stress would compromise plastic encapsulants - a key differentiator confirmed in the Ordering Information and Package Outline sections of the MAX806TMJA datasheet.