Analog Devices Inc./Maxim Integrated MAX6370KA+T

Overview

MAX6370KA+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. Used in automotive and industrial controllers to detect software hangs and trigger system reset or interrupt.

For engineers reviewing the MAX6370KA+T datasheet, MAX6370KA+T pinout, MAX6370KA+T application, or MAX6370KA+T equivalent, key selection criteria include its push-pull WDO output timing, SET0–SET2 programmable timing configuration, low 8µA supply current, -40°C to +125°C operating range, and SOT23-8 package compatibility with space-constrained PCB layouts.

Technical Context

The MAX6370KA+T implements a dual-phase supervision architecture: an initial startup delay (programmable via SET0–SET2) precedes activation of the main watchdog timeout counter. The internal timer clears on every valid WDI edge (rising or falling ≥100ns), and asserts WDO low for exactly 1ms if no transition occurs before timeout expiration.

Its push-pull output eliminates external pull-up requirements, supports direct interface to µP reset inputs or interrupt controllers, and guarantees VOL ≤0.4V at ISINK = 6mA. Timing parameters are fully determined by static logic levels on SET0/SET1/SET2 - no configuration registers or I²C/SPI interface required.

Key Specifications

Pinout & Package

MAX6370KA+T is housed in an 8-pin SOT23 package (package code K8SN+1), measuring 2.9mm × 1.6mm × 1.1mm, with RoHS-compliant lead-free finish. 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 MAX6369KA+T, MAX6370KA+T eliminates pull-up dependency and shortens reset pulse for faster recovery; compared with MAX6372KA+T, it offers full timing configurability at the cost of slightly higher design effort for SET pin routing.

Availability

MAX6370KA+T is available at Aetrix Electronics and suitable for automotive ECUs, industrial PLCs, and medical infusion pumps requiring stable component supply, long-term lifecycle support, and AEC-Q100-aligned reliability.

Supply support for MAX6370KA+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 delivers hardware-based system supervision with pin-configurable timing - engineered specifically for µP monitoring in safety-critical embedded systems where firmware-only watchdogs pose unacceptable risk.

FAQ

What is the watchdog output type and drive capability of the MAX6370KA+T?

The MAX6370KA+T features a push-pull active-low watchdog output (WDO) capable of sinking up to 6mA at VCC > 4.5V while maintaining VOL ≤ 0.4V. Unlike open-drain variants, it requires no external pull-up resistor and can directly drive µP reset inputs or interrupt controllers. This design simplifies PCB layout and improves noise immunity in electrically harsh environments where the MAX6370KA+T is commonly deployed.

How do the SET0, SET1, and SET2 pins configure timing on the MAX6370KA+T?

The SET0, SET1, and SET2 pins on the MAX6370KA+T are static logic inputs that jointly select both startup delay and watchdog timeout periods from eight possible combinations - ranging from 1ms to 60s. For example, tying SET2=GND, SET1=GND, SET0=VCC selects a 10ms startup delay and 30ms timeout. The MAX6370KA+T datasheet Table 1 defines all valid configurations, and timing changes take effect after a 300µs internal setup time.

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

Yes, the MAX6370KA+T watchdog can be disabled dynamically by setting SET2=VCC, SET1=GND, SET0=VCC (logic pattern 101). In this mode, WDO remains high and the internal timer stops counting. The MAX6370KA+T resumes normal operation immediately upon changing to any other valid SET pin combination - no power cycle or reset is needed. This feature enables safe firmware updates or debug sessions without removing hardware supervision.

What is the minimum WDI pulse width requirement for the MAX6370KA+T?

The MAX6370KA+T requires a minimum WDI pulse width of 100ns for either rising or falling edge detection. Transitions narrower than this are ignored by the internal transition detector, preventing false clearing due to noise or glitches. This specification is guaranteed across the full -40°C to +125°C operating range and ensures robust operation in noisy industrial or automotive environments where the MAX6370KA+T is routinely applied.

Does the MAX6370KA+T meet automotive qualification standards?

The MAX6370KA+T is specified for operation from -40°C to +125°C and packaged in a RoHS-compliant SOT23-8 (K8SN+1), but it is not explicitly AEC-Q100 qualified. Only MAX6369KA/V+T and MAX6374KA/V+T in this family carry AEC-Q100 qualification. For automotive applications requiring formal qualification, designers should verify compliance documentation directly with Analog Devices or select a /V+ variant - the MAX6370KA+T remains suitable for non-qualified automotive subsystems where temperature and reliability margins are sufficient.