Analog Devices Inc./Maxim Integrated MAX809MEUR+T

Overview

MAX809MEUR+T from Maxim Integrated is a 3-pin SOT23-packaged microprocessor supervisory circuit with push-pull active-low RESET output, 4.38V reset threshold (±2.5% over −40°C to +105°C), 140ms minimum reset timeout, and 12μA supply current at +25°C. It monitors +5V or +3.3V power rails in embedded controllers and portable systems to prevent erroneous code execution during power-up, brownout, or power-down.

For engineers reviewing the MAX809MEUR+T datasheet, MAX809MEUR+T pinout, MAX809MEUR+T application, or MAX809MEUR+T equivalent, this page delivers verified electrical parameters, thermal operating limits, reset timing behavior, package dimensions, and validated alternative parts for industrial and automotive-grade designs requiring reliable power-on reset assertion.

Technical Context

The MAX809MEUR+T implements a precision voltage comparator with hysteresis-free threshold detection referenced to an internal bandgap, guaranteeing valid reset assertion down to VCC = +1V. Its push-pull output drives CMOS logic directly without external pullup components and remains functional across full industrial temperature range (−40°C to +105°C).

Reset timeout is internally timed using a temperature-compensated RC oscillator, delivering ≥140ms minimum active period after VCC rises above threshold-guaranteed across voltage and temperature. The device rejects fast VCC transients up to 100mV overdrive for ≤20μs, eliminating false resets in noisy environments.

Key Specifications

Pinout & Package

MAX809MEUR+T uses a 3-pin SOT23 package (JEDEC MO-178AA, 1.3mm × 2.9mm × 1.0mm body height) with GND on Pin 1, RESET on Pin 2, and VCC on Pin 3. Thermal resistance θ_JA = 250°C/W; rated for 320mW continuous dissipation at +70°C (derates 4mW/°C above).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX809MEUR+T, TLV809MDBZR offers lower cost but sacrifices automotive qualification and high-temp reliability, while ADM809MARZ-REEL provides tighter initial accuracy but misaligns with the 4.38V threshold needed for robust +5V rail supervision-making MAX809MEUR+T the optimal choice for industrial and automotive applications demanding guaranteed reset timing across full temperature range.

Availability

MAX809MEUR+T is available at Aetrix Electronics and suitable for industrial PLC controllers, automotive body control modules, portable medical monitors, and smart energy meters requiring stable component supply, long-term lifecycle support, and AEC-Q100-compliant performance.

Supply support for MAX809MEUR+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) designs precision analog and mixed-signal ICs for industrial, automotive, communications, and computing markets, with emphasis on high-reliability power management and interface solutions.

The MAX809 series belongs to Maxim's microprocessor supervisory product line, engineered specifically for deterministic power-on reset generation in safety-critical embedded systems where supply rail integrity must be continuously verified across extreme temperature and noise conditions.

FAQ

What is the exact reset threshold voltage of the MAX809MEUR+T and how does it vary with temperature?

The MAX809MEUR+T has a nominal reset threshold of 4.38V, with guaranteed limits of 4.25V (min) to 4.50V (max) over −40°C to +85°C, and 4.20V to 4.56V over −40°C to +125°C. This 2.5% tolerance ensures consistent reset assertion before logic failure on +5V rails. The device exhibits ≤30ppm/°C tempco, minimizing drift across operating temperature.

Does the MAX809MEUR+T require an external pullup resistor on its RESET pin?

No, the MAX809MEUR+T features a push-pull active-low RESET output and does not require an external pullup resistor. It actively drives the output low during reset and high when released, providing direct CMOS-compatible logic levels. This eliminates BOM cost and layout complexity associated with open-drain alternatives like the MAX803.

What is the minimum VCC voltage at which the MAX809MEUR+T guarantees correct RESET output logic state?

The MAX809MEUR+T guarantees correct RESET output logic state down to VCC = +1V. Below this voltage, the output enters high-impedance state. This specification ensures deterministic reset behavior during deep brownout conditions, preventing metastability in connected microprocessors before power fully collapses.

Can the MAX809MEUR+T be used in automotive applications, and what qualification does it hold?

Yes, the MAX809MEUR+T is AEC-Q100 qualified for automotive applications. Its SOT23 package version (EUR) is rated for operation from −40°C to +105°C, making it suitable for under-hood and cabin modules including body control units, infotainment power sequencing, and ADAS sensor subsystems requiring robust reset supervision.

How long is the reset pulse width generated by the MAX809MEUR+T after VCC rises above the threshold?

The MAX809MEUR+T asserts RESET for a minimum of 140ms after VCC rises above the reset threshold. This timeout is guaranteed across temperature and supply voltage, with typical values ranging from 240ms to 560ms depending on conditions. The internal timing circuit ensures compliance with JEDEC and Intel power-on reset timing standards.