Analog Devices Inc./Maxim Integrated MAX809JEUR

Overview

MAX809JEUR from Maxim Integrated is a 3-pin SOT23-packaged microprocessor supervisory circuit with push-pull active-low RESET output, 4.00V ±3% reset threshold (at +25°C), 140ms minimum reset timeout, 12μA typical supply current, and guaranteed operation down to VCC = +1V. It monitors +5V digital systems to prevent erroneous code execution during power-up, brownout, or power-down events in industrial controllers and portable instrumentation.

For engineers reviewing the MAX809JEUR datasheet, MAX809JEUR pinout, MAX809JEUR application, or MAX809JEUR equivalent, this page delivers verified electrical parameters, thermal performance across –40°C to +105°C, SOT23 package compatibility, and validated alternatives for reset supervision in battery-powered and automotive-qualified designs.

Technical Context

The MAX809JEUR implements a precision bandgap-based voltage comparator with 30ppm/°C tempco to detect VCC falling below 4.00V, asserting RESET low until VCC rises above threshold and remains stable for ≥140ms. Its push-pull output drives CMOS inputs directly without external pullup resistors.

Designed for immunity to fast transients, it ignores negative-going VCC glitches ≤20μs when overdriven by 100mV below threshold, and guarantees valid RESET logic state for VCC as low as +1V-enabling reliable reset assertion even during deep brownout conditions.

Key Specifications

Pinout & Package

MAX809JEUR is housed in a 3-pin SOT23 package (package code U3+1), with 1.3mm × 2.9mm footprint, 0.95mm height, and gull-wing leads compatible with standard reflow profiles (peak 260°C).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS3808G33DBVR and STM6823RWDY6F, the MAX809JEUR uniquely combines +5V-system-optimized 4.00V threshold, 140ms factory-trimmed timeout, and full –40°C to +105°C qualification in a minimal 3-pin SOT23 footprint-making it optimal for space-constrained industrial and automotive reset supervision where timing precision and thermal robustness are critical.

Availability

MAX809JEUR is available at Aetrix Electronics and suitable for industrial controllers, portable medical instruments, and automotive body control modules requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX809JEUR 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, and communications applications, with emphasis on reliability, integration, and low-power operation.

The MAX809JEUR belongs to Maxim's microprocessor supervisory product line, engineered specifically to replace discrete reset solutions in +5V digital systems-delivering guaranteed reset timing, high noise immunity, and minimal board space usage.

FAQ

What is the reset threshold voltage of the MAX809JEUR and how does it vary with temperature?

The MAX809JEUR has a nominal reset threshold of 4.00V at +25°C, with ±3% initial accuracy. Over the full operating range of –40°C to +105°C, the threshold varies between 3.80V and 4.20V, exhibiting a tempco of 30ppm/°C. This tight drift ensures predictable brownout detection across industrial ambient conditions without requiring system-level recalibration. The MAX809JEUR maintains this specification without external components.

Does the MAX809JEUR require an external pullup resistor on its RESET pin?

No, the MAX809JEUR features a push-pull active-low RESET output and does not require an external pullup resistor. Unlike open-drain variants such as the MAX803, its output actively drives both high and low states, enabling direct interface with standard CMOS reset inputs. This simplifies PCB layout, reduces BOM count, and improves noise immunity compared to pullup-dependent configurations.

What is the minimum VCC voltage at which the MAX809JEUR guarantees correct RESET logic state?

The MAX809JEUR guarantees valid RESET logic state down to VCC = +1V. Below this level, the output may become indeterminate-but since most microprocessors cease functional operation below 1V, this specification ensures deterministic reset behavior throughout the entire usable supply range. For applications requiring validity down to 0V, external pull-down resistors are recommended per Maxim's application guidance.

How does the MAX809JEUR handle fast transients on the VCC supply line?

The MAX809JEUR incorporates comparator hysteresis and internal filtering to reject fast VCC transients: it ignores negative-going glitches ≤20μs wide when the supply dips 100mV below the 4.00V threshold. This immunity prevents false resets caused by switching regulator noise or ESD events. A 0.1μF bypass capacitor placed near the VCC pin further enhances robustness against higher-frequency disturbances.

Is the MAX809JEUR qualified for automotive applications?

The MAX809JEUR is not explicitly AEC-Q100 qualified-the /V automotive-grade variants (e.g., MAX809JEUR/V+) carry that qualification. However, the MAX809JEUR operates over –40°C to +105°C and meets all electrical specifications required for many non-safety-critical automotive subsystems, including body control modules and infotainment power sequencing. For ASIL-B or higher compliance, the /V+ suffix version must be selected.