Analog Devices Inc./Maxim Integrated MAX6324HUT44+T

Overview

MAX6324HUT44+T from Maxim Integrated is an automotive-grade microprocessor supervisory circuit with windowed (min/max) watchdog, open-drain RESET output, and factory-trimmed 4.38V reset threshold (±2.5% accuracy). It monitors +5.0V supply rails in harsh environments, asserts RESET down to VCC = +1.2V, and delivers 1ms WDPO fault pulses for fast/slow timing violations. Used in engine control units and ADAS domain controllers.

For engineers reviewing the MAX6324HUT44+T datasheet, MAX6324HUT44+T pinout, MAX6324HUT44+T application, or MAX6324HUT44+T equivalent, key selection criteria include AEC-Q100 qualification, SOT23-6 package compatibility, guaranteed reset validity at low VCC, and dual-window watchdog timeout behavior with H-suffix (719ms fast / 1.3s slow).

Technical Context

The MAX6324HUT44+T implements a laser-trimmed windowed 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 upon detection. Its internal reset comparator guarantees valid RESET assertion down to VCC = +1.2V and holds RESET active ≥100ms after VCC recovery.

It features debounced manual reset (MR) with 1μs minimum pulse width and 100ns glitch immunity, open-drain WDPO and RESET outputs rated for 20mA sink, and operates across -40°C to +125°C with BiCMOS process technology. The device requires no external components for basic operation beyond 500pF VCC bypass.

Key Specifications

Pinout & Package

MAX6324HUT44+T is housed in a RoHS-compliant, lead-free 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 board.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6324HUT44+T, MAX6324HUT46+T offers higher reset voltage headroom while maintaining identical watchdog behavior and footprint, whereas TLV809E50DBZR sacrifices supervision intelligence for ultra-low power and smaller size - making it unsuitable for AEC-Q100 safety-critical roles.

Availability

MAX6324HUT44+T is available at Aetrix Electronics and suitable for automotive engine control, ADAS domain controllers, and electric power steering modules requiring stable component supply with AEC-Q100 qualification and extended temperature operation.

Supply support for MAX6324HUT44+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 applications, with emphasis on high-reliability, low-power solutions.

The MAX6323/MAX6324 product line delivers AEC-Q100-qualified microprocessor supervisors with windowed watchdogs specifically for automotive safety-critical systems requiring deterministic fault detection and robust power monitoring.

FAQ

What is the exact reset threshold voltage of MAX6324HUT44+T and how tightly is it specified?

The MAX6324HUT44+T has a nominal reset threshold of 4.38V, with guaranteed range of 4.25V to 4.50V over -40°C to +125°C. This ±2.5% accuracy is achieved via laser trimming and ensures consistent brownout detection for +5.0V systems without external calibration. The "44" suffix in MAX6324HUT44+T explicitly denotes this threshold variant.

Does MAX6324HUT44+T support watchdog supervision for both fast and slow timing faults, and what are the actual timeout values?

Yes, MAX6324HUT44+T implements true windowed (min/max) watchdog supervision. With the "H" suffix, its fast timeout window is 719ms (min) to 1.3s (max), and slow timeout is 1.3s (min) to 1.8s (max). These values are factory-laser-trimmed and tested across temperature - enabling detection of both premature and delayed WDI pulses in safety-critical firmware loops.

How does the open-drain RESET output of MAX6324HUT44+T differ from the push-pull version, and why is it used in automotive designs?

The MAX6324HUT44+T uses an open-drain RESET output (unlike MAX6323's push-pull), requiring an external pullup resistor. This allows level-shifting across voltage domains - e.g., monitoring a 5V rail while driving a 3.3V microcontroller RESET pin. In automotive applications, it enables shared reset busing and simplifies interfacing with bidirectional μP reset pins, as confirmed in the MAX6324HUT44+T datasheet Figure 7.

Is MAX6324HUT44+T qualified for automotive use, and what specific AEC-Q100 grade does it meet?

Yes, MAX6324HUT44+T is AEC-Q100 qualified. The "/V" designation in its full ordering code (MAX6324HUT44/V+T) confirms Grade 0 qualification for operation from -40°C to +125°C ambient temperature. This makes it suitable for under-hood and safety-critical applications including engine control, braking, and steering systems per ISO 26262 requirements.

What is the minimum VCC voltage at which MAX6324HUT44+T guarantees valid RESET output assertion?

MAX6324HUT44+T guarantees valid RESET output assertion down to VCC = +1.2V, as explicitly stated in the datasheet General Description and Electrical Characteristics table. Below this voltage, the internal circuitry cannot sink sufficient current to maintain a defined logic low - a critical specification for reliable operation during automotive cold-cranking scenarios where battery voltage dips below 6V.