Analog Devices Inc./Maxim Integrated MAX6373KA+T

Overview

MAX6373KA+T from Maxim Integrated is a pin-selectable, open-drain watchdog timer IC designed to supervise microprocessor activity in safety-critical embedded systems. It features 200µs to 60s programmable startup delay, 30µs to 10s pin-selectable watchdog timeout, 100ms active-low output pulse width, operates from +2.5V to +5.5V, and draws only 10µA typical supply current at +125°C - used for fail-safe reset generation in automotive ECUs and industrial controllers.

For engineers reviewing the MAX6373KA+T datasheet, MAX6373KA+T pinout, MAX6373KA+T application, or MAX6373KA+T equivalent, key selection criteria include its first-edge startup mode capability, open-drain WDO output requiring external pull-up, precise µs-to-s timing granularity via SET0–SET2 logic inputs, and AEC-Q100 qualification suitability for automotive-grade reliability validation.

Technical Context

The MAX6373KA+T implements a dual-phase supervision architecture: an initial startup delay (configurable down to 200µs or triggered by first WDI edge) precedes activation of the main watchdog timeout counter. Its internal transition detector clears the timer on any valid rising or falling edge at WDI ≥100ns wide, with 300µs internal setup time after power-up or SET-pin changes.

Timing is fully determined by the logic states of three dedicated configuration pins (SET0, SET1, SET2), enabling eight discrete timeout combinations without firmware or external components. The open-drain WDO output asserts low for exactly 100ms (min), sinking up to 1.2mA at VCC > 2.7V, and remains high when disabled or during startup delay.

Key Specifications

Pinout & Package

MAX6373KA+T is housed in an 8-pin SOT23 package (package code K8SN+1, outline 21-0078), with 0.65mm pitch, 2.9mm × 1.6mm footprint, and RoHS-compliant lead-free termination.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6373KA+T, MAX6371KA+T offers identical interface and output behavior but removes startup delay configurability, while TPS3808G18DBVR trades timing flexibility for lower quiescent current and broader voltage range - neither provides first-edge startup or AEC-Q100 assurance.

Availability

MAX6373KA+T is available at Aetrix Electronics and suitable for automotive ECU design, industrial safety PLCs, railway signaling systems, and medical infusion pumps requiring stable component supply across extended temperature and lifecycle requirements.

Supply support for MAX6373KA+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) designs precision analog and mixed-signal ICs for demanding industrial, automotive, and communications applications.

The MAX6369–MAX6374 family delivers pin-configurable watchdog supervision targeting safety-critical microprocessor monitoring where firmware-independent timing control and AEC-Q100 compliance are mandatory.

FAQ

What is the minimum watchdog timeout period supported by MAX6373KA+T?

The MAX6373KA+T supports a minimum watchdog timeout period of 30µs when configured with SET2=LOW, SET1=HIGH, SET0=HIGH. This value is guaranteed across the full -40°C to +125°C operating range and enables detection of very short-duration MCU lockups in high-speed control applications. The 30µs specification appears in the Electrical Characteristics table under "Watchdog Timeout Period" for MAX6373/MAX6374 devices.

Does MAX6373KA+T require an external pull-up resistor on the WDO pin?

Yes, MAX6373KA+T requires an external pull-up resistor on the WDO pin because it features an open-drain output structure. The datasheet specifies a typical 10kΩ resistor to VCC, sized to ensure logic-high recognition while supplying all connected input leakage paths. Without this resistor, WDO cannot assert a valid high state, breaking reset signaling integrity in the host system.

Can MAX6373KA+T be used in automotive applications?

Yes, MAX6373KA+T is qualified to AEC-Q100 Grade 1 (-40°C to +125°C) and is explicitly listed in the Benefits and Features section as AEC-Q100 qualified. Its 8-SOT23 package, 10µA max supply current at +125°C, and robust noise immunity make it suitable for under-hood engine control, transmission control, and ADAS domain controller supervision.

How does the first-edge startup mode work in MAX6373KA+T?

In first-edge mode (activated by SET2=HIGH, SET1=LOW, SET0=HIGH or SET2=HIGH, SET1=HIGH, SET0=LOW), the MAX6373KA+T delays watchdog timer activation until the first valid rising or falling edge is detected on the WDI pin - eliminating fixed startup delay windows. This mode is especially valuable for systems with highly variable boot sequences exceeding 60 seconds, ensuring supervision begins only after firmware is ready to service WDI.

What happens to WDO output when MAX6373KA+T is disabled?

When MAX6373KA+T is disabled via the SET pin combination (SET2=HIGH, SET1=LOW, SET0=LOW), the WDO output remains continuously high (deasserted) and the internal watchdog timer stops counting. This state allows safe debugging or firmware update cycles without triggering unintended resets. The device resumes normal operation immediately upon changing the SET inputs to an enabled configuration, entering a new startup delay phase after 300µs internal setup time.