Analog Devices Inc./Maxim Integrated MAX6370KA/V+T

Overview

MAX6370KA/V+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, 1ms–60s pin-selectable startup delay and timeout periods, and operates from +2.5V to +5.5V over –40°C to +125°C. It is used to reset or interrupt μP upon code execution failure in automotive and industrial controllers.

For engineers reviewing the MAX6370KA/V+T datasheet, MAX6370KA/V+T pinout, MAX6370KA/V+T application, or MAX6370KA/V+T equivalent, key selection criteria include its AEC-Q100 qualification, push-pull WDO output timing, pin-configurable timeout granularity, and operation across extended temperature and supply voltage ranges without external components.

Technical Context

The MAX6370KA/V+T implements a digital watchdog timer with three logic-controlled SET pins (SET0/SET1/SET2) that configure both startup delay and normal timeout periods independently. Its internal transition detector clears the timer on any valid rising or falling edge at WDI, with 100ns minimum pulse width requirement and 300μs internal setup time after power-up or setting changes.

This device uses BiCMOS process technology and integrates 1500 transistors. Unlike open-drain variants (e.g., MAX6369), it delivers a push-pull WDO output capable of sourcing/sinking current without external pull-up, enabling direct interface to μP reset inputs or interrupt lines with 1ms guaranteed assertion time.

Key Specifications

Pinout & Package

Package: 8-pin SOT23 (K8SN+1), RoHS-compliant lead(Pb)-free, tape-and-reel packaging (2500 pcs/reel).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6372KA+T, MAX6370KA/V+T offers full pin-selectable startup and timeout timing, enabling adaptation to variable boot sequences; compared with TLV809E33DBZR, it provides true runtime code-execution supervision rather than static power-on reset only.

Availability

MAX6370KA/V+T is available at Aetrix Electronics and suitable for automotive ECU, industrial PLC, medical infusion pump, railway signaling, and telecom base station applications requiring stable component supply across extended temperature and voltage ranges.

Supply support for MAX6370KA/V+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 and mixed-signal ICs for demanding industrial, automotive, and communications applications.

The MAX6369–MAX6374 family was developed specifically for high-reliability microprocessor supervision in safety-critical systems where deterministic watchdog timing and AEC-Q100 compliance are mandatory.

FAQ

What is the watchdog output type and pulse width of the MAX6370KA/V+T?

The MAX6370KA/V+T features a push-pull active-low watchdog output (WDO) with a guaranteed minimum pulse width of 1ms. This eliminates the need for an external pull-up resistor and allows direct interfacing with microprocessor reset inputs or interrupt controllers. The 1ms duration ensures robust latching in downstream logic, even under marginal voltage or capacitive loading conditions. Unlike open-drain variants such as MAX6369, the MAX6370KA/V+T drives both high and low states actively.

Does the MAX6370KA/V+T support AEC-Q100 qualification?

Yes, the MAX6370KA/V+T is AEC-Q100 qualified (Grade 0), rated for operation from –40°C to +125°C. The "/V" suffix explicitly denotes automotive qualification, and the "+T" indicates lead(Pb)-free tape-and-reel packaging. This qualification covers stress testing for temperature cycling, humidity, mechanical shock, and ESD - confirming suitability for engine control, transmission, and ADAS applications where reliability under thermal and electrical stress is critical. The MAX6370KA/V+T shares this qualification with MAX6374KA/V+T but not with non-/V variants.

How are startup delay and watchdog timeout configured on the MAX6370KA/V+T?

Startup delay and watchdog timeout on the MAX6370KA/V+T are configured using three logic inputs: SET0 (pin 4), SET1 (pin 5), and SET2 (pin 6). Each pin is hardwired to either VCC or GND to select one of eight timing combinations - e.g., SET2=0, SET1=0, SET0=0 yields 1ms startup delay and 1ms timeout, while SET2=1, SET1=1, SET0=1 selects 60s for both. These settings are sampled at power-up and after any change, with a 300μs internal setup time before new timing takes effect. No firmware or serial interface is required.

Can the MAX6370KA/V+T watchdog be disabled without power cycling?

Yes, the MAX6370KA/V+T watchdog function can be disabled dynamically by setting SET2=VCC, SET1=GND, and SET0=GND - a configuration that halts timer operation and holds WDO high. This mode is fully reversible: changing any SET pin re-enables the watchdog with the new timing parameters after the 300μs setup time. Disabling is useful during firmware debugging, factory test modes, or safe maintenance windows. Importantly, WDO remains deasserted (high) in disable mode, avoiding unintended system resets.

What is the supply current and operating voltage range of the MAX6370KA/V+T?

The MAX6370KA/V+T draws only 8µA typical supply current (ICC) at +25°C and operates across a wide +2.5V to +5.5V supply range. At full temperature range (–40°C to +125°C), ICC remains below 22µA. This ultra-low quiescent current enables use in battery-backed or energy-constrained systems, while the broad voltage range supports direct connection to unregulated 3.3V or 5V rails - eliminating the need for dedicated LDOs in many designs. The device also tolerates VCC slew rates down to 0.05V/μs, preventing false resets during slow power ramps.