Analog Devices Inc./Maxim Integrated MAX6324HUT29+T

Overview

MAX6324HUT29+T from Maxim Integrated is an automotive-grade microprocessor supervisory circuit with windowed (min/max) watchdog, open-drain RESET output, and factory-trimmed 2.93V reset threshold (±2.5% accuracy). It monitors +2.5V to +5.5V supplies, guarantees valid RESET down to VCC = +1.2V, and operates across –40°C to +125°C for engine control units and safety-critical embedded systems.

For engineers reviewing the MAX6324HUT29+T datasheet, MAX6324HUT29+T pinout, MAX6324HUT29+T application, or MAX6324HUT29+T equivalent, key selection criteria include its H-windowed watchdog timeout (719ms fast / 1.3s slow), 23µA typical supply current, AEC-Q100 qualification, and SOT23-6 open-drain interface compatibility with bidirectional μP reset pins.

Technical Context

The MAX6324HUT29+T implements a dual-threshold watchdog that detects both fast faults (WDI falling edges <719ms apart) and slow faults (no WDI edge >1.3s), with WDPO pulsed low for 1ms on fault detection. Its internal reset comparator guarantees monotonic assertion/deassertion with 20µs response to VCC transients.

RESET is open-drain and requires external pullup; it remains asserted ≥100ms after VCC rises above 2.93V and MR deasserts. The MR input features internal 85kΩ pullup, 1µs minimum pulse width, and 100ns glitch immunity - enabling direct switch connection without external debouncing.

Key Specifications

Pinout & Package

MAX6324HUT29+T is housed in a RoHS-compliant 6-pin SOT23 package (package code U6+1A, outline 21-0058), optimized for high-density automotive PCB layouts with thermal resistance θJA = 115°C/W on multilayer boards.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar microprocessor supervisory applications.

Compared with MAX6324HUT29+T, MAX6324HUT44/V+T offers identical watchdog performance but targets 5V systems, while TLV809E29DBVR reduces cost and power at the expense of runtime fault detection capability - making it unsuitable for ASIL-B or ADAS use cases.

Availability

MAX6324HUT29+T is available at Aetrix Electronics and suitable for automotive engine control, advanced driver assistance systems, and electric power steering applications requiring stable component supply with AEC-Q100 compliance and extended temperature support.

Supply support for MAX6324HUT29+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 automotive, industrial, and communications markets with emphasis on reliability and integration.

The MAX6324 series delivers AEC-Q100-qualified supervisory circuits specifically engineered for functional safety in automotive powertrain and chassis control systems requiring deterministic watchdog supervision and robust reset generation.

FAQ

What is the exact reset threshold voltage of MAX6324HUT29+T and how tightly is it specified?

The MAX6324HUT29+T has a nominal reset threshold of 2.93V, with a guaranteed range of 2.85V to 3.00V (±2.5%) across the full operating temperature range of –40°C to +125°C. This tight tolerance ensures consistent brownout detection in automotive environments where supply rails fluctuate significantly during cranking or load dump events. The laser-trimmed threshold eliminates need for external calibration in MAX6324HUT29+T-based designs.

Does MAX6324HUT29+T support windowed watchdog functionality, and what are the specific timeout values?

Yes, MAX6324HUT29+T implements a true windowed (min/max) watchdog using the H-window configuration: fast timeout is 719ms (min 543ms, max 719ms), and slow timeout is 1.3s (min 1.3s, max 1.8s). This dual-threshold architecture detects both premature and delayed WDI pulses - essential for validating deterministic execution in safety-critical firmware. The timeouts are factory-laser-trimmed and do not require external components.

How does the open-drain RESET output of MAX6324HUT29+T interface with microcontrollers having bidirectional reset pins?

The open-drain RESET output of MAX6324HUT29+T connects directly to bidirectional μP reset pins (e.g., Motorola 68HC11) using a single external pullup resistor. This configuration allows either the MAX6324HUT29+T or the μP to assert reset - enabling coordinated system recovery. The pullup can connect to any supply up to +6V, supporting level-shifting between monitored and control domains without additional logic.

Is MAX6324HUT29+T qualified for automotive applications, and what standards does it meet?

Yes, MAX6324HUT29+T is AEC-Q100 qualified for automotive Grade 0 (–40°C to +125°C), meeting stringent reliability and stress-test requirements for powertrain and chassis control systems. It is designed for engine control units, ADAS processors, and EPS modules where functional safety and long-term stability under thermal cycling are mandatory. The "/V" suffix in related variants explicitly denotes automotive qualification, and MAX6324HUT29+T inherits this status.

What is the minimum supply voltage at which MAX6324HUT29+T guarantees valid RESET output assertion?

MAX6324HUT29+T guarantees valid RESET output assertion down to VCC = +1.2V, ensuring reliable reset generation even during deep brownout conditions common in automotive stop-start systems. Below +1.2V, the internal circuitry cannot sink current, so the open-drain RESET output transitions to high-impedance - a known failure mode that aligns with μP shutdown behavior. This specification is verified across temperature and process corners for MAX6324HUT29+T.