Analog Devices Inc./Maxim Integrated MAX6369KA-T

Overview

MAX6369KA-T 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 and watchdog timeout periods selectable via SET0/SET1/SET2 pins - used in automotive engine control units to detect firmware lockup and trigger safe reset.

For engineers reviewing the MAX6369KA-T datasheet, MAX6369KA-T pinout, MAX6369KA-T application, or MAX6369KA-T equivalent, key selection criteria include its 100ms watchdog output pulse width, 8-pin SOT23 package, AEC-Q100 qualification (for /V variants), pin-selectable timing (1ms–60s), and open-drain output requiring external pull-up - all critical for fail-safe μP monitoring in harsh environments.

Technical Context

The MAX6369KA-T implements a precision analog/digital hybrid watchdog timer with three logic-controlled SET inputs that configure both startup delay and normal timeout periods independently. Its internal transition detector validates rising/falling edges on WDI ≥100ns wide, and ignores input during WDO assertion or 300µs internal setup time after power-up or setting changes.

It uses BiCMOS process technology (1500 transistors) and features a dedicated watchdog disable mode (SET2=1, SET1=0, SET0=1), enabling runtime reconfiguration without power cycling. The open-drain WDO output sinks up to 1.2mA at 0.3V low-level voltage, requiring an external pull-up resistor (e.g., 10kΩ) to any supply ≤+5.5V.

Key Specifications

Pinout & Package

MAX6369KA-T is housed in an 8-pin SOT23 package (package code K8SN-1/K8SN+1, outline 21-0078), measuring 2.9mm × 1.6mm × 1.1mm, with RoHS-compliant lead-free plating (+ suffix). Pin 3 is N.C. and must remain unconnected.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6369KA-T, MAX6371KA-T offers fixed startup timing but identical supervision behavior and pin compatibility, while TPS3808G33DBVR trades timing configurability and voltage range for lower power and faster reset - making MAX6369KA-T optimal for automotive and industrial designs requiring field-programmable timing and wide supply tolerance.

Availability

MAX6369KA-T is available at Aetrix Electronics and suitable for automotive engine control units, industrial PLC safety monitors, and medical infusion pump controllers requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for MAX6369KA-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 high-performance analog, mixed-signal, and power management ICs for demanding industrial, automotive, and communications applications.

The MAX6369–MAX6374 family was designed specifically for hardware-level microprocessor supervision in safety-critical systems where firmware-based watchdogs are insufficient - emphasizing configurability, low power, and rugged operation.

FAQ

What is the watchdog output type and drive capability of the MAX6369KA-T?

The MAX6369KA-T features an open-drain, active-low watchdog output (WDO) capable of sinking ≥1.2mA while maintaining V_OL ≤0.3V at VCC > 2.7V. This requires an external pull-up resistor (typically 10kΩ) to a logic rail ≤+5.5V. Unlike push-pull variants (e.g., MAX6370), it does not source current - enabling wired-OR configurations and voltage-level translation in mixed-supply systems. The 100–300ms pulse width ensures reliable reset assertion across diverse μP reset input thresholds.

How do the SET0, SET1, and SET2 pins configure timing on the MAX6369KA-T?

On the MAX6369KA-T, the logic states (VCC or GND) applied to SET0, SET1, and SET2 determine both startup delay and watchdog timeout periods from eight possible combinations. For example, SET2=0/SET1=0/SET0=0 yields 1ms for both delays, while SET2=1/SET1=1/SET0=1 selects 60s. The pattern SET2=1/SET1=0/SET0=1 disables the watchdog entirely. These pins may be hardwired or driven dynamically - allowing runtime reconfiguration without power cycling. All timing values are guaranteed over -40°C to +125°C.

Is the MAX6369KA-T qualified for automotive applications?

The MAX6369KA-T itself is not AEC-Q100 qualified; only the /V variants (e.g., MAX6369KA/V+T) carry AEC-Q100 Grade 1 (-40°C to +125°C) certification. However, the MAX6369KA-T shares identical electrical specifications, package, and operating temperature range (-40°C to +125°C), making it suitable for non-certified automotive subsystems such as infotainment gateways or body control modules where formal qualification is not mandated. For ASIL-B or higher systems, the /V+ variant must be specified.

What is the minimum valid watchdog input pulse width for the MAX6369KA-T?

The MAX6369KA-T requires a minimum WDI pulse width of 100ns for reliable edge detection. Transitions (rising or falling) narrower than this are ignored by the internal transition detector. This specification holds across the full operating temperature range and supply voltage (2.5V–5.5V). Additionally, WDI transitions are masked during WDO assertion and for up to 300µs after power-up or timing configuration changes - ensuring robust operation during system initialization and dynamic reprogramming.

Does the MAX6369KA-T require external passive components to operate?

No, the MAX6369KA-T requires no external timing components - all watchdog timing is generated internally using precision analog circuitry and digital logic. Only two external elements are recommended: a 0.1µF ceramic bypass capacitor between VCC and GND (placed ≤0.2 inches from the device) for noise immunity, and a pull-up resistor on WDO (e.g., 10kΩ to 3.3V or 5V) to establish the logic-high state. No capacitors, resistors, or crystals are needed for core watchdog functionality - reducing BOM cost and PCB footprint.