Analog Devices Inc./Maxim Integrated MAX6374KA-T

Overview

MAX6374KA-T from Maxim Integrated is a pin-selectable watchdog timer IC designed to supervise microprocessor activity in safety-critical embedded systems. It features push-pull active-low watchdog output with 1ms pulse width, operates from +2.5V to +5.5V, draws only 10–22µA supply current over –40°C to +125°C, and supports startup delay and timeout periods selectable via SET0/SET1/SET2 pins - used in automotive control units and industrial PLCs for fail-safe reset signaling.

For engineers reviewing the MAX6374KA-T datasheet, MAX6374KA-T pinout, MAX6374KA-T application, or MAX6374KA-T equivalent, key selection criteria include its 1ms push-pull WDO pulse, first-edge startup mode capability, 30µs minimum watchdog timeout, AEC-Q100 qualification (via /V+ variant), and compatibility with noisy environments requiring robust μP supervision without external timing components.

Technical Context

The MAX6374KA-T implements a digital watchdog timer with three logic-controlled configuration pins (SET0/SET1/SET2) that determine both startup delay and normal timeout periods. Its internal transition detector monitors rising/falling edges on WDI ≥100ns wide, ignoring inputs during WDO assertion and a 300µs internal setup window after power-up or setting changes.

This device belongs to the MAX6369–MAX6374 family and specifically uses push-pull output architecture - unlike open-drain variants - enabling direct drive of reset inputs without pull-up resistors. It supports two extended startup modes (SET2=1, SET1=0/1, SET0=1/0) where the timer initiates only upon first valid WDI edge, eliminating fixed initialization time constraints.

Key Specifications

Pinout & Package

MAX6374KA-T is housed in an 8-pin SOT23 package (package code K8SN-1/K8SN+1), footprint-compatible with JEDEC MS-012AC, land pattern 90-0176, and rated for reflow up to +260°C (lead-free).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6374KA-T, MAX6374KA/V+T offers identical functionality with added automotive qualification, while TPS3823DBVR trades timing flexibility and push-pull drive for lower cost and simpler configuration - making it viable only where programmability and fast reset pulse are noncritical.

Availability

MAX6374KA-T is available at Aetrix Electronics and suitable for automotive engine control, industrial PLCs, medical infusion pumps, and railway signaling interfaces requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6374KA-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 high-reliability ICs for demanding industrial, automotive, and medical applications.

The MAX6369–MAX6374 family delivers configurable watchdog supervision targeting safety-critical embedded systems where deterministic reset timing, low power, and environmental ruggedness are essential.

FAQ

What is the watchdog output type and pulse width of the MAX6374KA-T?

The MAX6374KA-T features a push-pull, active-low watchdog output (WDO) with a guaranteed minimum pulse width of 1ms. This allows direct connection to microprocessor reset inputs without requiring an external pull-up resistor - unlike open-drain variants such as MAX6373KA-T. The 1ms duration ensures sufficient hold time for reliable reset assertion across voltage and temperature extremes, and is specified under all operating conditions from –40°C to +125°C.

Does the MAX6374KA-T support first-edge startup mode, and how is it configured?

Yes, the MAX6374KA-T supports first-edge startup mode - a feature unique to MAX6373/MAX6374 variants. It is enabled by setting SET2 = high, SET1 = low, SET0 = high (101) or SET2 = high, SET1 = high, SET0 = low (110). In this mode, the watchdog timer does not begin counting until the first valid WDI transition occurs, eliminating fixed startup delay assumptions. This is especially valuable in systems with variable or lengthy initialization sequences, and is fully documented in Table 1 of the MAX6374KA-T datasheet.

What are the minimum and maximum watchdog timeout periods supported by the MAX6374KA-T?

The MAX6374KA-T supports watchdog timeout periods ranging from 30µs to 10s, selected via the SET0/SET1/SET2 pins. Minimum values include 30µs (SET2=0, SET1=1, SET0=1), 3ms (SET2=0, SET1=0, SET0=0), and 1s (SET2=1, SET1=0, SET0=1); maximum values reach 10s (SET2=1, SET1=1, SET0=1). All timeout options are guaranteed over –40°C to +125°C and do not require recalibration - enabling precise fault-detection timing for real-time safety-critical applications.

Is the MAX6374KA-T AEC-Q100 qualified, and what does that mean for automotive use?

The MAX6374KA-T itself is not AEC-Q100 qualified; however, the functionally identical MAX6374KA/V+T variant is explicitly qualified per AEC-Q100 Rev H Grade 1 (–40°C to +125°C). Both share identical electrical specifications, pinout, and SOT23-8 packaging. For automotive production, MAX6374KA/V+T must be used to meet qualification requirements - including stress testing, failure analysis, and traceable lot documentation - while MAX6374KA-T remains suitable for industrial and medical prototyping where full automotive certification is not mandated.

How does the MAX6374KA-T handle noise immunity on the WDI input?

The MAX6374KA-T requires WDI transitions to be ≥100ns wide to register as valid, inherently filtering out sub-100ns glitches. Additionally, the device ignores WDI transitions during WDO assertion and for up to 300µs after power-up or timing-setting changes - preventing false timeouts during unstable states. For electrically noisy environments, Maxim recommends placing a 0.1µF ceramic bypass capacitor between VCC and GND within 0.2 inches of the MAX6374KA-T package, which suppresses supply rail noise that could otherwise couple into WDI through internal coupling paths.