Analog Devices Inc./Maxim Integrated MAX812SEUS

Overview

MAX812SEUS from Maxim Integrated is an active-high microprocessor supervisory circuit in a 4-pin SOT143 package, designed to monitor 3V power supplies with a nominal reset threshold of 2.93V. It asserts RESET when VCC falls below threshold, maintains reset for ≥140ms after recovery, and features a debounced manual reset input (MR) with internal 20kΩ pull-up. Used in portable battery-powered equipment for reliable power-on/brownout reset control.

For engineers reviewing the MAX812SEUS datasheet, MAX812SEUS pinout, MAX812SEUS application, or MAX812SEUS equivalent, key selection criteria include reset threshold accuracy (±1.5% over temperature), guaranteed RESET validity during VCC > 1V, MR glitch immunity (≤100ns), and ultra-low 6µA supply current at +25°C.

Technical Context

The MAX812SEUS implements a precision bandgap-based voltage comparator with fixed 2.93V threshold optimized for 3V systems, paired with a monostable timer that enforces minimum 140ms reset pulse width after VCC recovery. Its active-high RESET output drives loads up to 1.2mA while sinking ≤0.4V at VCC = VTH(MIN).

Manual reset is initiated by pulling MR low; RESET remains asserted for tRP = 140–560ms after MR returns high. The device ignores transients ≤100ns and exhibits ±30ppm/°C reset threshold tempco, ensuring stable operation across –40°C to +85°C.

Key Specifications

Pinout & Package

Package: 4-pin SOT143 (3.5mm × 1.75mm × 1.0mm body, 0.95mm max height), surface-mount, lead-free compatible.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS3123E18DBVR and ADM6710LAKSZ-RL, the MAX812SEUS uniquely combines 2.93V threshold, integrated MR with internal pull-up, 4-pin SOT143 footprint, and guaranteed 140ms reset pulse-making it optimal for space-constrained 3V portable designs requiring manual reset capability.

Availability

MAX812SEUS is available at Aetrix Electronics and suitable for portable medical devices, industrial PLC controllers, and smart energy meters requiring stable component supply with guaranteed long-term availability.

Supply support for MAX812SEUS 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, automotive, and communications markets.

The MAX811/MAX812 family was designed specifically for low-power microprocessor supervision in battery-operated and space-constrained systems, emphasizing minimal external components and robust transient immunity.

FAQ

What is the exact reset threshold voltage for MAX812SEUS?

The MAX812SEUS has a nominal reset threshold voltage of 2.93V, with ±1.5% accuracy over the full –40°C to +85°C temperature range. This value is laser-trimmed at wafer test and specified in the Electrical Characteristics table under VTH parameter for the 'S' suffix variant. The threshold ensures reliable reset assertion before downstream 3V logic ICs fall outside their guaranteed operating range.

Does MAX812SEUS support manual reset functionality, and how is it implemented?

Yes, MAX812SEUS supports manual reset via its MR pin, which is active-low with an internal 20kΩ pull-up resistor. Pulling MR to GND initiates a reset, and RESET remains asserted for 140–560ms after MR returns high. No external components are needed-just a normally open momentary switch between MR and GND provides fully debounced manual reset, eliminating PCB space and BOM cost.

What is the maximum supply voltage the MAX812SEUS can tolerate on VCC?

The MAX812SEUS has an absolute maximum VCC rating of 6.0V, but its functional operating range is 1.2V to 5.5V. Operation above 5.5V risks permanent damage, while operation below 1.2V may result in undefined RESET behavior. For 3V systems using the MAX812SEUS, VCC should be maintained within 2.7V–3.6V to ensure proper reset threshold margin and timing compliance.

How does MAX812SEUS handle power supply transients, and what is its immunity specification?

The MAX812SEUS rejects short-duration negative-going VCC transients up to 100ns wide, as confirmed in the Electrical Characteristics table under "MR Glitch Immunity." For a 2.93V threshold device (S suffix), transients ≤20µs duration and ≤125mV below VTH will not trigger a reset. This immunity is achieved through internal comparator hysteresis and filtering, making MAX812SEUS suitable for noisy industrial power rails.

Is the MAX812SEUS pin-compatible with other members of the MAX811/MAX812 family?

Yes, all MAX811/MAX812 variants-including MAX812SEUS-are pin-compatible in the 4-pin SOT143 package. VCC, MR, RESET, and GND assignments are identical across L/M/T/S/R suffixes and between MAX811 (active-low) and MAX812 (active-high) versions. Only the reset threshold voltage and output polarity differ; PCB layout requires no changes when substituting within the same package and function type.