Analog Devices Inc./Maxim Integrated MAX812LEUS

Overview

MAX812LEUS from Maxim Integrated is an active-high microprocessor supervisory circuit in a 4-pin SOT143 package, designed to monitor 5V power supplies with a precision 4.63V reset threshold. It asserts RESET for ≥140ms after VCC rises above threshold, features 6µA supply current, and includes a debounced manual reset input (MR) for system-level control in embedded controllers and portable equipment.

For engineers reviewing the MAX812LEUS datasheet, MAX812LEUS pinout, MAX812LEUS application, or MAX812LEUS equivalent, this device serves as a low-power, temperature-stable voltage monitor for reliable µP reset generation during power-up, brownout, and manual intervention-critical for industrial controllers, battery-powered instruments, and computing peripherals requiring deterministic reset timing and transient immunity.

Technical Context

The MAX812LEUS implements a precision bandgap-based voltage comparator with internal hysteresis to detect VCC drops below 4.63V ±1.5%, triggering an active-high RESET output. Its internal timer ensures minimum 140ms reset assertion after VCC recovery, independent of supply ramp rate.

It integrates a 20kΩ internal MR pull-up resistor, accepts TTL/CMOS-compatible logic levels on MR, and provides guaranteed RESET validity over –40°C to +85°C with <30ppm/°C reset threshold tempco-enabling robust operation in thermally varying environments without external calibration.

Key Specifications

Pinout & Package

MAX812LEUS is housed in a 4-pin SOT143 package (4.0 × 2.0 × 1.75 mm), optimized for high-density PCB layouts and reflow compatibility. The package features gull-wing leads and exposed die pad for thermal performance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS3808G15DBVR and ADM6710LAKSZ-REEL7, the MAX812LEUS delivers fixed 140ms reset timing with minimal external components and proven transient immunity-ideal for cost-sensitive, space-constrained applications where deterministic reset behavior without configurability is preferred.

Availability

MAX812LEUS is available at Aetrix Electronics and suitable for industrial controllers, portable medical devices, and embedded computing peripherals requiring stable component supply, long-term lifecycle support, and consistent parametric performance across temperature.

Supply support for MAX812LEUS 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 power, sensing, interface, and reliability-critical applications.

The MAX812LEUS belongs to Maxim's µP supervisory product line, engineered specifically for deterministic power-on reset generation in resource-constrained embedded systems using 5V rails-prioritizing low quiescent current, tight threshold accuracy, and robust noise immunity.

FAQ

What is the reset threshold voltage of the MAX812LEUS?

The MAX812LEUS has a nominal reset threshold voltage of 4.63V with a guaranteed tolerance of ±1.5% over the full operating temperature range (–40°C to +85°C). This value is laser-trimmed at wafer test and does not require external calibration. The threshold remains stable with a tempco of 30ppm/°C, making it suitable for 5V ±5% power supply monitoring in industrial and computing applications where precise brownout detection is essential.

Does the MAX812LEUS provide manual reset capability?

Yes, the MAX812LEUS includes a dedicated manual reset input (MR) pin that is active-low and internally pulled up to VCC with a 20kΩ resistor. Driving MR low asserts the active-high RESET output for the duration of the low signal plus a guaranteed 140ms timeout after MR returns high. This eliminates the need for external pull-up resistors or debounce circuitry-enabling direct connection to a momentary switch or logic controller for field-service or test-mode reset initiation.

What is the supply current consumption of the MAX812LEUS?

The MAX812LEUS draws only 6µA of supply current at +25°C, with typical values remaining below 10µA across the full –40°C to +85°C temperature range. This ultra-low quiescent current is achieved through optimized CMOS design and enables continuous power-supply monitoring in battery-powered applications such as portable medical instruments and remote sensors-supporting multi-year operational life on primary cells without compromising reset timing accuracy.

How does the MAX812LEUS handle power supply transients?

The MAX812LEUS incorporates inherent immunity to short-duration negative-going VCC transients: it rejects glitches ≤40µs wide when the supply dips ≥125mV below the 4.63V reset threshold. This is achieved via comparator hysteresis and internal filtering-eliminating false resets caused by switching regulator noise, ESD coupling, or cable-induced spikes. For enhanced immunity, a 0.1µF ceramic capacitor placed close to the VCC pin is recommended per the datasheet layout guidelines.

Is the MAX812LEUS pin-compatible with other members of the MAX811/MAX812 family?

Yes, the MAX812LEUS shares identical pinout, package (SOT143), and functional interface with all MAX812 variants (e.g., MAX812MEUS, MAX812TEUS) and MAX811 variants. The only differences between family members are reset threshold voltage (determined by suffix letter L/M/T/S/R) and RESET polarity (MAX811 = active-low, MAX812 = active-high). Therefore, substituting MAX812LEUS for another MAX812 variant requires no PCB changes-only verification that the 4.63V threshold meets the target system's supply tolerance requirements.