Analog Devices Inc./Maxim Integrated MAX6337US18D3

Overview

MAX6337US18D3 from Maxim Integrated is an ultra-low-voltage, open-drain microprocessor supervisory circuit designed to monitor 1.8V power supplies and assert a reliable active-low reset signal during brownout, power-up, or manual reset events. It features a factory-trimmed 1.80V reset threshold (±1.8% at +25°C, ±3% over -40°C to +125°C), 100ms minimum reset timeout, 3.3µA supply current at 1.8V, and guaranteed operation down to VCC = 1.0V. It is used in portable battery-powered equipment requiring robust power monitoring with minimal quiescent power.

For engineers reviewing the MAX6337US18D3 datasheet, MAX6337US18D3 pinout, MAX6337US18D3 application, or MAX6337US18D3 equivalent, key selection criteria include its open-drain RESET output for bidirectional µP interface compatibility, 1.8V threshold accuracy across temperature, 100ms reset pulse width, low 3.3µA ICC at 1.8V, and SOT143 package suitability for space-constrained embedded designs.

Technical Context

The MAX6337US18D3 implements a precision bandgap-based voltage comparator with hysteresis to detect VCC falling below 1.80V, coupled with a monostable timeout circuit that holds RESET asserted for ≥100ms after VCC recovery or MR deassertion. Its open-drain output enables wired-OR configuration and direct interfacing with bidirectional reset pins (e.g., Motorola 68HC11), requiring only an external pull-up resistor.

Reset assertion is immune to fast transients ≤24µs at 10V/ms slew rate, and the internal 20kΩ MR pull-up eliminates need for external components. The device operates across -40°C to +125°C and maintains valid RESET output down to VCC = 1.0V - unlike push/pull variants which guarantee validity to 0.7V.

Key Specifications

Pinout & Package

MAX6337US18D3 is housed in a 4-pin SOT143 package (3.0mm × 1.6mm × 0.9mm), optimized for high-density PCB layouts in portable and automotive applications. The package is RoHS-compliant and available in both leaded (-T) and lead-free (+T) variants.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6336US18D3-T and MAX6315US18D3-T, the MAX6337US18D3 offers unique open-drain flexibility for shared reset buses and bidirectional µP interfaces, while maintaining identical threshold accuracy and timeout - making it optimal for space-constrained, multi-device reset architectures where wiring simplicity and interoperability outweigh the need for push/pull drive.

Availability

MAX6337US18D3 is available at Aetrix Electronics and suitable for portable medical sensors, automotive body control modules, industrial IoT edge nodes, and smart meter data loggers requiring stable component supply with guaranteed long-term availability.

Supply support for MAX6337US18D3 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) is a semiconductor company specializing in high-performance analog, mixed-signal, and power-management ICs for industrial, automotive, communications, and computing applications.

The MAX633x family was designed specifically for ultra-low-voltage microprocessor supervision in battery-powered and harsh-environment systems, emphasizing precision threshold accuracy, sub-µA quiescent current, and robust transient immunity.

FAQ

What is the factory-trimmed reset threshold voltage for MAX6337US18D3?

The MAX6337US18D3 has a factory-trimmed reset threshold of 1.80V, with ±1.8% tolerance at +25°C and ±3% over the full operating temperature range of -40°C to +125°C. This value is confirmed in Table 1 of the official datasheet and applies specifically to the "US18" suffix variant. The MAX6337US18D3 uses this exact threshold to supervise 1.8V power rails without external calibration.

Does MAX6337US18D3 support manual reset functionality?

Yes, the MAX6337US18D3 includes a dedicated MR (manual reset) input (Pin 3) that asserts reset when pulled low. It features internal 20kΩ pull-up resistance, so the pin can be left unconnected if unused. A normally open momentary switch between MR and GND provides fully debounced manual reset - no external RC network is required. This behavior is explicitly documented in the Applications Information section of the MAX6337US18D3 datasheet.

What is the minimum supply voltage at which MAX6337US18D3 guarantees correct reset output behavior?

The MAX6337US18D3 guarantees correct RESET output behavior down to VCC = 1.0V, as stated in the General Description and Absolute Maximum Ratings sections of its datasheet. This is distinct from the MAX6335/MAX6336 variants, which guarantee operation to 0.7V. Below 1.0V, the open-drain output may lose sinking capability, so system design must ensure critical reset actions complete before VCC falls further.

What package type and dimensions does MAX6337US18D3 use?

The MAX6337US18D3 is packaged in a 4-pin SOT143 (also referenced as SOT-143) with dimensions of 3.0mm × 1.6mm × 0.9mm. This compact surface-mount package is specified in the Package Information section and shown in the Pin Configuration diagram. It is available in both leaded (-T) and lead-free (+T) versions, with top-mark code KAAY for traceability.

How does the open-drain output of MAX6337US18D3 differ from push/pull outputs in the same family?

The MAX6337US18D3 features an open-drain RESET output (Pin 2), requiring an external pull-up resistor to define the high state - enabling wired-OR configurations and direct interface with bidirectional µP reset pins like those on the Motorola 68HC11. In contrast, MAX6335/MAX6336 variants use push/pull outputs that actively drive both high and low. This structural difference makes the MAX6337US18D3 uniquely suited for multi-master reset buses where multiple devices share one reset line.