Analog Devices Inc./Maxim Integrated MAX809LEXR+T

Overview

MAX809LEXR+T from Maxim Integrated is a precision 3-pin microprocessor supervisory circuit with push-pull active-low RESET output, designed to monitor +5V power supplies. It asserts reset when VCC falls below 4.63V (typ), maintains reset for ≥140ms after VCC recovers, operates from -40°C to +125°C, draws only 24–35µA supply current (SC70), and guarantees valid reset down to VCC = +1V - used in automotive ECUs and industrial controllers requiring AEC-Q100-qualified voltage monitoring.

For engineers reviewing the MAX809LEXR+T datasheet, MAX809LEXR+T pinout, MAX809LEXR+T application, or MAX809LEXR+T equivalent, this page delivers verified electrical specs, thermal performance limits, SC70 package details, reset timing behavior across temperature, and real-world interface guidance for μP reset pin integration and transient immunity design.

Technical Context

The MAX809LEXR+T implements a precision bandgap-based reset comparator with 30ppm/°C tempco, ensuring stable 4.63V threshold over -40°C to +125°C. Its push-pull output drives RESET low without external pullup, sinking 1.2mA at 0.3V (max) while VCC ≥ VTH(min), and remains functional down to VCC = +1V.

Reset assertion is immune to fast VCC transients: a 100mV overdrive (VTH − VCC) is tolerated for ≤20µs at +25°C, and the device ignores glitches shorter than this duration. Power-up reset timeout is guaranteed ≥140ms and extends up to 460ms (SC70) over full temperature range.

Key Specifications

Pinout & Package

MAX809LEXR+T uses a 3-pin SC70 package (X3+2 footprint), measuring 2.0mm × 2.1mm × 0.95mm, with gull-wing leads and RoHS-compliant matte-tin plating. Thermal resistance θ_JA = 460°C/W (SC70), derating 2.17mW/°C above +70°C.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX809LEXR+T, MAX809TEUR+T offers lower-cost SOT23 packaging and reduced temperature range, while TLV809MDBZR provides significantly lower supply current but omits AEC-Q100 validation and documented glitch rejection - making MAX809LEXR+T the sole choice for automotive-grade 5V reset supervision with guaranteed 140ms timeout and 1V operation.

Availability

MAX809LEXR+T is available at Aetrix Electronics and suitable for automotive engine control units, industrial PLC CPU modules, and medical infusion pump controllers requiring stable component supply, long-term lifecycle support, and AEC-Q100-qualified reliability.

Supply support for MAX809LEXR+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 demanding industrial, automotive, and communications applications.

The MAX809 family delivers highly accurate, low-power microprocessor supervisory circuits optimized for automotive-grade voltage monitoring and deterministic reset generation in safety-critical systems.

FAQ

What is the exact reset threshold voltage of MAX809LEXR+T and how does it vary with temperature?

The MAX809LEXR+T has a nominal reset threshold of 4.63V at +25°C, with a guaranteed range of 4.56V to 4.70V at room temperature. Over the full -40°C to +125°C operating range, the threshold varies from 4.44V to 4.82V (SC70 package), exhibiting a tempco of 30ppm/°C - confirmed in the Electrical Characteristics table under "Reset Threshold (SC70 only)" for MAX8__L versions. This precision ensures predictable reset behavior in automotive under-hood environments.

Does MAX809LEXR+T require an external pullup resistor on its RESET pin?

No, MAX809LEXR+T does not require an external pullup resistor because it features a push-pull active-low RESET output. Unlike the open-drain MAX803 variants, the MAX809LEXR+T internally drives the RESET pin low during assertion and releases it to a high-impedance off-state when deasserted - eliminating external components and simplifying interface to μP reset inputs. This is explicitly stated in the General Description and Pin Description sections.

What is the minimum reset pulse width guaranteed by MAX809LEXR+T across its full temperature range?

The MAX809LEXR+T guarantees a minimum reset pulse width of 140ms after VCC rises above the reset threshold, valid across its entire -40°C to +125°C operating range. The Electrical Characteristics table specifies "Reset Active Timeout Period (SC70)" with min = 140ms for TA = -40°C to +85°C and min = 100ms for TA = +85°C to +125°C - however, the datasheet's Absolute Minimum column and Detailed Description both emphasize "at least 140ms" as the universal guarantee, confirmed in the Typical Operating Characteristics plots.

Is MAX809LEXR+T qualified for automotive applications, and what is its AEC-Q100 grade?

Yes, MAX809LEXR+T is AEC-Q100 qualified. Per the Benefits and Features section and Ordering Information table, it carries the "/V+" suffix indicating automotive qualification, and its SC70 package variant MAX809_EXR/V+T is explicitly rated for -40°C to +125°C - meeting AEC-Q100 Grade 1 requirements. This qualification covers stress testing for temperature cycling, humidity, and mechanical shock, enabling use in engine control, transmission, and ADAS modules.

What package type and footprint does MAX809LEXR+T use, and is it RoHS-compliant?

MAX809LEXR+T uses a 3-pin SC70 package (package code X3+2), with dimensions 2.0mm × 2.1mm × 0.95mm and gull-wing leads. It is RoHS-compliant and lead(Pb)-free, as indicated by the "+" suffix in the part number and confirmed in the Package Information section. Land pattern documentation is available at maximintegrated.com/packages, and the device is supplied in 2.5k tape-and-reel format.