Analog Devices Inc./Maxim Integrated MAX6371KA

Overview

MAX6371KA from Maxim Integrated is a pin-selectable watchdog timer supervisor IC designed to monitor microprocessor activity in safety-critical embedded systems. It features open-drain active-low WDO output with 100ms minimum pulse width, fixed 60s startup delay, and pin-selectable watchdog timeout periods from 1ms to 60s. It operates from +2.5V to +5.5V, draws only 8µA supply current, and is housed in an 8-pin SOT23 package for industrial controller and automotive monitoring applications.

For engineers reviewing the MAX6371KA datasheet, MAX6371KA pinout, MAX6371KA application, or MAX6371KA equivalent, this page delivers verified timing parameters, confirmed pin functions, exact package mapping (SOT23-8), and two validated alternative parts - all directly traceable to Maxim's official documentation and electrical characteristics table.

Technical Context

The MAX6371KA implements a precision analog/digital watchdog timer with three logic-controlled SET pins (SET0–SET2) that configure timing without power cycling. Its fixed 60s startup delay ensures full µP initialization before supervision begins, while its eight selectable timeout options (1ms–60s) are determined solely by SET pin states - no external components required.

It uses an internal edge-detection circuit on WDI to clear the watchdog timer on any valid rising or falling transition ≥100ns wide. The open-drain WDO output requires an external pull-up and asserts low for ≥100ms upon timeout, enabling direct reset or interrupt signaling to microcontrollers in telecom and networking equipment.

Key Specifications

Pinout & Package

MAX6371KA is packaged in an 8-pin SOT23-8 surface-mount package with standard footprint and thermal profile for high-density PCB layouts.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar watchdog timer applications.

Compared with MAX6371KA, MAX6370KA and MAX6372KA provide push-pull WDO outputs for improved noise margin and faster signal rise/fall, while retaining identical pin-selectable timing and 60s startup delay - making them drop-in alternatives only when open-drain drive is not required.

Availability

MAX6371KA is available at Aetrix Electronics and suitable for industrial PLC monitoring, automotive body control modules, and telecom base station controllers requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6371KA 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, mixed-signal, and power management ICs for demanding industrial, automotive, and communications applications.

The MAX6369–MAX6374 family was engineered specifically for reliable µP supervision in harsh environments - delivering pin-configurable timing, ultra-low power, and robust ESD/EMI performance without external components.

FAQ

What is the watchdog timeout range supported by MAX6371KA?

The MAX6371KA supports eight pin-selectable watchdog timeout periods ranging from 1ms to 60s. These intervals are configured using the logic states of SET0, SET1, and SET2 pins - for example, SET2=0/SET1=0/SET0=0 yields 1ms, while SET2=1/SET1=1/SET0=1 selects 60s. All values are minimum guaranteed durations per Maxim's Electrical Characteristics table.

Does MAX6371KA require an external pull-up resistor on the WDO pin?

Yes, MAX6371KA requires an external pull-up resistor on the WDO pin because it features an open-drain output. A 10kΩ resistor to VCC (≤+5.5V) is recommended per the datasheet to ensure proper logic-high level while accommodating leakage and load currents. Without this pull-up, WDO cannot assert a valid high state between pulses.

Can the MAX6371KA watchdog be disabled without power cycling?

Yes, the MAX6371KA watchdog can be disabled dynamically without power cycling by setting SET2=VCC, SET1=0, and SET0=0. This configuration halts watchdog supervision while maintaining power and allowing safe firmware debugging. To re-enable, simply change the SET pin states to any enabled combination - the device enters a new startup phase after a 300µs internal setup time.

What is the purpose of the fixed 60s startup delay in MAX6371KA?

The fixed 60s startup delay in MAX6371KA ensures the monitored microprocessor completes full power-on initialization, bootloader execution, and peripheral configuration before watchdog supervision begins. This prevents spurious timeouts during boot - a critical requirement in automotive and industrial systems where µP startup sequences exceed typical watchdog windows.

How does MAX6371KA handle noisy WDI signals in electrically harsh environments?

MAX6371KA requires a 0.1µF bypass capacitor placed between VCC and GND within 0.2 inches of the package to suppress supply noise. Additionally, its WDI input ignores transitions during the 60s startup delay and for up to 300µs after power-up or SET pin changes - reducing susceptibility to glitches during power transients or configuration updates.