Analog Devices Inc./Maxim Integrated MAX6337US18D3+T

Overview

MAX6337US18D3+T from Maxim Integrated is an ultra-low-voltage, open-drain microprocessor supervisory circuit designed for 1.8V power supply monitoring in space-constrained embedded systems. It asserts an active-low RESET signal when VCC falls below 1.80V (±1.8% at +25°C) or when the debounced manual-reset input (MR) is asserted, with a guaranteed minimum reset timeout of 100ms and valid operation down to VCC = 1.0V. Used in portable equipment and automotive controllers where precise brownout detection and low quiescent current are critical.

For engineers reviewing the MAX6337US18D3+T datasheet, MAX6337US18D3+T pinout, MAX6337US18D3+T application, or MAX6337US18D3+T equivalent, key selection criteria include its 1.8V factory-trimmed reset threshold, 100ms minimum timeout, open-drain output architecture for bidirectional µP reset pin interfacing, and guaranteed functional validity at VCC ≥1.0V - all in a 4-pin SOT143 package.

Technical Context

The MAX6337US18D3+T implements a precision voltage comparator with factory-trimmed 1.80V reset threshold (±1.8% at +25°C, ±3% over –40°C to +125°C), immune to fast VCC transients up to 24µs at 10V/ms slew rate. Its internal MR input includes a 20kΩ pull-up resistor and supports debounced manual reset with 160µs minimum pulse width at VCC = 2.6V.

This device uses an open-drain RESET output requiring an external pull-up resistor, enabling direct interface with bidirectional microcontroller reset pins (e.g., Motorola 68HC11). Unlike push/pull variants, it does not guarantee RESET validity down to VCC = 0 due to reduced sinking capability below 1.0V.

Key Specifications

Pinout & Package

MAX6337US18D3+T is housed in a 4-pin SOT143 surface-mount package (3.0mm × 1.6mm × 0.9mm), optimized for high-density PCB layouts. The package features gull-wing leads and is available in lead-free format (+T suffix).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6336US18D3+T and MAX811TEUS+T, the MAX6337US18D3+T uniquely supports 1.8V rail supervision with open-drain flexibility, making it optimal for mixed-voltage systems and bidirectional µP interfaces - but requires external pull-up and does not guarantee reset validity below 1.0V.

Availability

MAX6337US18D3+T is available at Aetrix Electronics and suitable for portable/battery-powered equipment, automotive engine control units, and intelligent industrial instruments requiring stable component supply across extended temperature ranges and long production lifecycles.

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

The MAX6335/MAX6336/MAX6337 family delivers ultra-low-voltage, low-power microprocessor supervisory circuits targeting space-constrained, battery-sensitive applications where precision reset thresholds and minimal external components are essential.

FAQ

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

The MAX6337US18D3+T 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 laser-trimmed during production and specified in Table 1 of the datasheet; it ensures accurate brownout detection for 1.8V digital systems without external calibration.

Does MAX6337US18D3+T support manual reset, and how is it implemented?

Yes, MAX6337US18D3+T includes a debounced manual-reset input (MR) that requires no external components. A logic-low pulse on MR asserts RESET; the internal 20kΩ pull-up resistor holds MR high when unused. The minimum MR pulse width is 160µs at VCC = 2.6V, and the device guarantees proper reset assertion and timeout even during low-VCC conditions down to 1.0V.

Why does MAX6337US18D3+T use an open-drain output instead of push/pull?

The open-drain RESET output of MAX6337US18D3+T enables wired-OR configuration with other reset sources and direct interface with microcontrollers featuring bidirectional reset pins (e.g., Motorola 68HC11). It requires an external pull-up resistor but avoids output contention - a critical advantage in multi-source reset architectures where multiple devices share the same reset line.

What is the minimum supply voltage at which MAX6337US18D3+T guarantees correct RESET state?

MAX6337US18D3+T guarantees correct RESET assertion and deassertion down to VCC = 1.0V, unlike the MAX6335/MAX6336 variants which guarantee operation to 0.7V. Below 1.0V, sinking capability degrades and RESET may become indeterminate - so the device is not recommended for applications requiring valid reset signaling below 1.0V.

Is MAX6337US18D3+T pin-compatible with other members of the MAX633x family?

Yes, MAX6337US18D3+T shares identical 4-pin SOT143 pinout and footprint with MAX6335US18D3+T and MAX6336US18D3+T, as well as with MAX811/MAX812 and MAX6314/MAX6315 families. This allows drop-in replacement in existing layouts when switching between push/pull and open-drain output types - provided the external pull-up resistor is added for the MAX6337 variant.