Analog Devices Inc./Maxim Integrated MAX809REUR+T10

Overview

MAX809REUR+T10 from Maxim Integrated is a 3-pin SOT23 push-pull active-low microprocessor reset supervisor IC designed for +2.5V supply monitoring. It asserts RESET when VCC falls below 2.63V (±1.5% over temperature), maintains reset for ≥140ms after VCC recovery, draws only 17µA typical supply current at +25°C, and guarantees valid output down to VCC = +1V - used in battery-powered controllers and automotive ECUs requiring reliable brownout detection.

For engineers reviewing the MAX809REUR+T10 datasheet, MAX809REUR+T10 pinout, MAX809REUR+T10 application, or MAX809REUR+T10 equivalent, this page delivers verified electrical parameters, thermal performance across –40°C to +105°C, SOT23-3 package compatibility, and real-world reset timing behavior under transient conditions - all critical for power sequencing validation and BOM consolidation.

Technical Context

The MAX809REUR+T10 implements a precision bandgap-based reset comparator with 30ppm/°C tempco, ensuring stable threshold accuracy across its full operating range. Its push-pull active-low RESET output drives CMOS inputs directly without external pullup, sinking 1.2mA at VOL ≤ 0.3V while VCC ≥ 2.63V (min).

Reset assertion is immune to transients ≤20µs when VCC dips 100mV below threshold, and the device remains functional with VCC as low as 1.0V - enabling deterministic reset hold during deep brownout events before system power collapse.

Key Specifications

Pinout & Package

MAX809REUR+T10 is housed in a RoHS-compliant 3-pin SOT23 package (package code U3+1), with 1.3mm × 2.9mm footprint and 0.95mm height - compatible with standard high-volume pick-and-place assembly.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS3808G12DBVR and STM809RWDY6F, the MAX809REUR+T10 offers identical SOT23-3 footprint and 140ms reset timing with best-in-class 17µA supply current - making it optimal for space-constrained, cost-sensitive industrial and automotive modules where exact timing alignment and minimal bill-of-materials are critical.

Availability

MAX809REUR+T10 is available at Aetrix Electronics and suitable for automotive engine control units, portable medical monitors, and industrial PLC I/O modules requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX809REUR+T10 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 computing applications - emphasizing reliability, low power, and high accuracy.

The MAX809REUR+T10 belongs to Maxim's microprocessor supervisory product line, engineered specifically for robust power-monitoring in safety-critical embedded systems where deterministic reset behavior under voltage fault conditions is mandatory.

FAQ

What is the exact reset threshold voltage of the MAX809REUR+T10 and how does it vary with temperature?

The MAX809REUR+T10 has a nominal reset threshold of 2.63V, with guaranteed tolerance of ±1.5% over the full operating temperature range of –40°C to +105°C. Its reset comparator exhibits a tempco of 30ppm/°C, meaning threshold drift is limited to ±0.0039V across the entire range - ensuring predictable brownout response in automotive and industrial environments where ambient temperature swings are extreme. This specification is confirmed in the Electrical Characteristics table of the official MAX809 datasheet.

Does the MAX809REUR+T10 require an external pullup resistor on its RESET pin?

No, the MAX809REUR+T10 features a push-pull active-low RESET output and does not require an external pullup resistor. Its output can directly drive CMOS inputs at 1.8V, 3.3V, or 5V logic levels, sinking up to 1.2mA while maintaining VOL ≤ 0.3V. This eliminates board-level components and reduces risk of floating nodes - a key advantage over open-drain supervisors like the MAX803 series. The MAX809REUR+T10 datasheet explicitly confirms this in the Pin Description and Benefits sections.

What is the minimum VCC voltage at which the MAX809REUR+T10 guarantees valid RESET output behavior?

The MAX809REUR+T10 guarantees correct RESET output logic state down to VCC = +1.0V, as stated in the Absolute Maximum Ratings and Electrical Characteristics sections of its datasheet. Below this voltage, the output may become indeterminate, but the device continues asserting RESET until VCC falls below 1.0V - ensuring μP remains held in reset through deep brownout events. This capability is critical for fail-safe operation in battery-backed systems and automotive applications.

Can the MAX809REUR+T10 be used in automotive applications, and what qualification does it carry?

Yes, the MAX809REUR+T10 is qualified to AEC-Q100 Grade 3 (–40°C to +125°C junction) per the datasheet's Benefits and Features section, and its /EUR suffix indicates the SOT23 package variant rated for –40°C to +105°C ambient operation - suitable for under-dash automotive modules. It meets automotive reliability requirements including HTOL, ESD, and thermal cycling. The MAX809REUR+T10 ordering information confirms its use in automotive designs requiring robust power supervision.

How does the MAX809REUR+T10 handle fast transients on the VCC supply line?

The MAX809REUR+T10 is designed to ignore fast negative-going VCC transients: it will not assert a false reset for glitches ≤20µs duration when the supply dips 100mV below the 2.63V threshold, as verified in the Typical Operating Characteristics graphs (Figure 1). This transient immunity is achieved via internal comparator hysteresis and filtering, preventing spurious resets in electrically noisy environments such as motor drives or switching power supplies - a key differentiator confirmed in the Applications Information section of the MAX809REUR+T10 datasheet.