Analog Devices Inc./Maxim Integrated MAX6369KA

Overview

MAX6369KA 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 minimum pulse width, selectable startup delay (1ms–60s), selectable watchdog timeout (1ms–60s), and operates from +2.5V to +5.5V supply. It is used to reset or interrupt µP systems upon code execution failure in industrial controllers and automotive ECUs.

For engineers reviewing the MAX6369KA datasheet, MAX6369KA pinout, MAX6369KA application, or MAX6369KA equivalent, key selection criteria include its 8-pin SOT23 package, 8µA supply current, pin-configurable timing without power cycling, and compatibility with noisy environments requiring bypass capacitor support.

Technical Context

The MAX6369KA implements a precision analog/digital hybrid watchdog timer with three logic-controlled SET pins (SET0/SET1/SET2) that jointly determine both startup delay and timeout period. Its internal transition detector monitors WDI edges (≥100ns wide), ignores inputs during WDO assertion and 300µs internal setup time, and clears the timer on every valid rising or falling edge.

It uses BiCMOS process technology (1500 transistors) and supports dynamic timing reconfiguration: changing SET pin states while WDO is deasserted initiates new timing immediately after 300µs setup; if asserted, it completes the prior timeout before entering new startup phase. The open-drain WDO requires external pull-up and sinks ≥1.2mA at VCC > 2.7V.

Key Specifications

Pinout & Package

MAX6369KA is housed in an 8-pin SOT23-8 package (top mark AADC), with 0.65mm pitch, 2.9mm × 2.8mm footprint, and thermal pad not connected. Pin 3 is NC and must remain unconnected.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6370KA and TPS3823-33DBVR, the MAX6369KA uniquely combines open-drain output compatibility, full pin-selectable timing (startup + timeout), and dual-voltage operation - making it the only option among the three suitable for industrial systems requiring flexible reset signaling and 2.5V–5.5V interoperability.

Availability

MAX6369KA is available at Aetrix Electronics and suitable for industrial PLC controllers, automotive engine control units, and telecom base station controllers requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6369KA 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 U.S.-based semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for industrial, automotive, and communications markets.

The MAX6369–MAX6374 family was designed specifically for robust µP supervision in harsh environments - emphasizing low power, timing configurability, and noise-immune operation without external components.

FAQ

What is the maximum supply voltage rating for MAX6369KA?

The MAX6369KA has an absolute maximum VCC rating of +6V, but its specified operating range is +2.5V to +5.5V. Operation above +5.5V risks permanent damage or parametric shift, and the device is not guaranteed to meet timing or logic thresholds beyond this range. Always limit VCC to ≤+5.5V in production designs using MAX6369KA.

Does MAX6369KA require an external pull-up resistor on the WDO pin?

Yes, MAX6369KA features an open-drain WDO output and requires an external pull-up resistor. A 10kΩ resistor to VCC (≤+5.5V) is recommended per the datasheet to ensure proper logic-high level while sinking ≥1.2mA during assertion. Omitting the pull-up will prevent WDO from reaching valid high state, causing system reset failure.

Can the watchdog timeout period of MAX6369KA be changed during normal operation?

Yes, the watchdog timeout period of MAX6369KA can be changed dynamically by altering the logic states of SET0, SET1, and SET2 pins without power cycling. After change, a 300µs internal setup time occurs; if WDO is deasserted, the new timing starts immediately post-setup; if asserted, the prior timeout completes first. This enables adaptive supervision in MAX6369KA-based systems.

What is the minimum pulse width of the WDO output on MAX6369KA?

The WDO output on MAX6369KA has a minimum pulse width of 100ms when asserted low. This value is guaranteed across temperature and supply voltage (–40°C to +85°C, +2.5V to +5.5V) and ensures sufficient duration to trigger standard µP reset circuits or interrupt controllers. Shorter pulses are not guaranteed and may result in unreliable reset assertion.

How does the MAX6369KA handle noise on the WDI input line?

The MAX6369KA requires WDI transitions to be ≥100ns wide to register as valid edges, providing inherent noise immunity. Additionally, the datasheet recommends a 0.1µF bypass capacitor between VCC and GND placed within 5mm of the device to suppress supply noise. WDI transitions are ignored during WDO assertion and the 300µs setup period - further reducing susceptibility to transient-induced false clears in MAX6369KA deployments.