Analog Devices Inc./Maxim Integrated MAX6371KA-T

Overview

MAX6371KA-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, 60s fixed startup delay, and pin-selectable watchdog timeout periods from 1ms to 60s. It operates from +2.5V to +5.5V and draws only 8–22µA supply current over –40°C to +125°C, making it suitable for automotive and industrial controller monitoring.

For engineers reviewing the MAX6371KA-T datasheet, MAX6371KA-T pinout, MAX6371KA-T application, or MAX6371KA-T equivalent, key selection criteria include its fixed 60s startup delay, open-drain WDO output requiring external pullup, pin-selectable timeout via SET0–SET2 logic inputs, and AEC-Q100 qualification (per MAX6371KA/V+T variant - not applicable to MAX6371KA-T).

Technical Context

The MAX6371KA-T implements a dual-phase supervision architecture: a fixed 60s startup delay precedes activation of the pin-configurable watchdog timeout counter. The internal timer clears on every valid rising or falling edge at WDI (≥100ns wide), and asserts WDO low for 100ms if no transition occurs before timeout expiration.

Timing configuration is achieved exclusively through static logic levels on three dedicated pins (SET0, SET1, SET2), enabling eight distinct timeout options without firmware or power cycling. Its open-drain output requires an external pullup resistor and sinks ≥1.2mA at VCC > 2.7V when asserted.

Key Specifications

Pinout & Package

MAX6371KA-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 gull-wing leads. This miniature footprint supports high-density PCB layouts in space-constrained applications such as automotive ECUs and industrial sensors.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6372KA+T, MAX6371KA-T provides longer WDO pulse width for robust reset assertion but lacks push-pull drive; compared with TPS3823-33DBVR, it offers voltage flexibility and timing configurability at higher unit cost and design complexity.

Availability

MAX6371KA-T is available at Aetrix Electronics and suitable for automotive engine control units, industrial PLC main controllers, railway signaling interface modules, and medical infusion pump controllers requiring stable component supply across extended temperature ranges and long production lifecycles.

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

The MAX6369–MAX6374 family delivers pin-configurable watchdog supervision targeting safety-critical embedded systems where software reliability must be enforced by hardware-level monitoring.

FAQ

What is the watchdog startup delay for MAX6371KA-T?

The MAX6371KA-T has a fixed 60-second startup delay before the watchdog timer begins counting its timeout period. This delay is not configurable and starts upon power-up or after any SET pin change. It ensures the microprocessor completes full initialization before supervision commences, preventing false resets during boot. The MAX6371KA-T does not support first-edge or variable startup delay modes - those are exclusive to MAX6373/MAX6374 variants.

Does MAX6371KA-T support pin-selectable watchdog timeout periods?

Yes, MAX6371KA-T supports eight pin-selectable watchdog timeout periods ranging from 1ms to 60s. These are configured using logic levels (VCC or GND) applied to the SET0, SET1, and SET2 pins. For example, SET2=0, SET1=0, SET0=0 yields 1ms timeout, while SET2=1, SET1=1, SET0=1 yields 60s. The timeout selection table is explicitly defined in the MAX6371 datasheet and applies identically to MAX6371KA-T.

What type of output does MAX6371KA-T provide on the WDO pin?

MAX6371KA-T provides an open-drain, active-low watchdog output on the WDO pin. It requires an external pullup resistor (typically 10kΩ) to a voltage rail up to +5.5V. When asserted, WDO sinks ≥1.2mA at VCC > 2.7V and holds low for a minimum of 100ms. This differs from push-pull variants like MAX6372KA+T, which drive high/low actively and deliver only 1ms pulses.

Can MAX6371KA-T be used in automotive applications?

MAX6371KA-T is rated for –40°C to +125°C operation and meets automotive environmental stress requirements, but it is not AEC-Q100 qualified. Only the MAX6371KA/V+T variant carries AEC-Q100 qualification. For production automotive applications requiring formal qualification, MAX6371KA/V+T must be selected; MAX6371KA-T may be used in prototyping, non-safety-critical subsystems, or industrial applications sharing similar temperature and reliability demands.

How does the WDI input function on MAX6371KA-T?

The WDI input on MAX6371KA-T resets the internal watchdog timer on each valid rising or falling edge (≥100ns wide). Transitions are ignored during the 60s startup delay, while WDO is asserted, and for up to 300µs after power-up or SET pin changes. To ensure reliable clearing, the microprocessor must toggle WDI at least once within the selected timeout window - for example, every 10ms if configured for 10ms timeout - and avoid sustained high/low states.