Analog Devices Inc./Maxim Integrated MAX6373KA+

Overview

MAX6373KA+ from Maxim Integrated is a pin-selectable watchdog timer IC designed to supervise microprocessor activity in safety-critical embedded systems. It features open-drain active-low WDO output with 100ms pulse width, operates from +2.5V to +5.5V, draws only 8–22µA supply current, and supports startup delay from 200µs to 60s and watchdog timeout from 30µs to 10s - used to reset or interrupt μP upon code execution failure.

For engineers reviewing the MAX6373KA+ datasheet, MAX6373KA+ pinout, MAX6373KA+ application, or MAX6373KA+ equivalent, key selection criteria include its pin-configurable timing (SET0/SET1/SET2), first-edge startup mode, open-drain output requiring external pullup, and operation across –40°C to +125°C for automotive and industrial reliability validation.

Technical Context

The MAX6373KA+ implements a precision analog/digital hybrid watchdog circuit with BiCMOS process technology (1500 transistors). Its internal timer clears on every valid rising or falling edge at WDI (≥100ns pulse width) and asserts WDO low after timeout - with no external components required.

Startup delay and watchdog timeout are independently controlled via three logic inputs (SET0/SET1/SET2), enabling eight discrete timing configurations. Two modes support "first edge" startup (SET2=1, SET1=0, SET0=1 or SET2=1, SET1=1, SET0=0), where the timer begins only upon first WDI transition - eliminating fixed initialization windows.

Key Specifications

Pinout & Package

MAX6373KA+ is housed in an 8-pin SOT23 package (package code K8SN+1, outline 21-0078), with 0.65mm pitch, footprint per land pattern 90-0176, and RoHS-compliant lead(Pb)-free construction.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6373KA+, MAX6371KA+ offers identical output behavior but sacrifices startup flexibility, while TPS3808G33DBVR reduces pin count and cost at the expense of configurability, voltage range, and first-edge capability - making MAX6373KA+ optimal for complex, multi-phase boot systems demanding precise, field-adjustable supervision.

Availability

MAX6373KA+ is available at Aetrix Electronics and suitable for automotive ECU, industrial PLC, medical device, telecom infrastructure, and battery-powered embedded systems requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for MAX6373KA+ 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 markets.

The MAX6369–MAX6374 family was designed specifically for robust, pin-configurable microprocessor supervision in harsh environments - emphasizing low power, wide temperature operation, and flexible timing without firmware intervention.

FAQ

What is the watchdog timeout range supported by MAX6373KA+?

The MAX6373KA+ supports a pin-selectable watchdog timeout range from 30µs to 10s, determined by the logic states of SET0, SET1, and SET2. Specific values include 3ms, 3s, 1s, 10s, and others per Table 1 in the datasheet. This range enables precise alignment with firmware loop durations in both real-time and long-cycle applications - critical for reliable supervision in the MAX6373KA+ design.

Does MAX6373KA+ support first-edge startup mode, and how is it configured?

Yes, MAX6373KA+ supports first-edge startup mode, which delays watchdog activation until the first valid WDI transition - ideal for systems requiring >60s initialization. It is enabled by setting SET2 = high, SET1 = low, SET0 = high (101) or SET2 = high, SET1 = high, SET0 = low (110). This mode is unique to MAX6373/MAX6374 variants and is explicitly documented for MAX6373KA+ in the datasheet's Table 1 and Detailed Description sections.

What is the WDO output structure of MAX6373KA+, and what external components are required?

MAX6373KA+ features an open-drain, active-low WDO output requiring an external pullup resistor (e.g., 10kΩ to VCC). The output sinks ≥1.2mA at 0.3V and provides a 100–300ms pulse on timeout. No other external components are needed - the MAX6373KA+ integrates all timing circuitry, eliminating capacitors or resistors for basic operation while maintaining compatibility with mixed-voltage systems up to +5.5V.

Can MAX6373KA+ be disabled during operation without power cycling?

Yes, MAX6373KA+ can be disabled during operation by setting SET2 = high, SET1 = low, SET0 = low (100), which places the device in watchdog disable mode. In this state, WDO remains high and the internal timer is halted. Re-enabling supervision requires changing the SET inputs to a valid timing configuration, followed by a 300µs internal setup time - all without power interruption. This capability is confirmed for MAX6373KA+ in the Applications Information section.

What is the supply current specification of MAX6373KA+ across temperature and voltage?

MAX6373KA+ draws 8–22µA supply current, with 8µA typical at +25°C and VCC = +3V. Over full operating conditions (–40°C to +125°C, VCC = +2.5V to +5.5V), ICC is guaranteed 10–22µA. This ultra-low quiescent current enables continuous supervision in energy-constrained applications - a core specification verified in the Electrical Characteristics table for MAX6373KA+.