Analog Devices Inc./Maxim Integrated MAX6324EUT26

Overview

MAX6324EUT26 from Maxim Integrated is an open-drain microprocessor supervisory circuit with windowed (min/max) watchdog, precision reset threshold of 2.63V ±2.5%, guaranteed RESET assertion down to VCC = +1.2V, and 100ms minimum reset timeout. It monitors power supplies and µP activity in automotive engine control units requiring fault-tolerant timing supervision.

For engineers reviewing the MAX6324EUT26 datasheet, MAX6324EUT26 pinout, MAX6324EUT26 application, or MAX6324EUT26 equivalent, key selection criteria include its factory-trimmed 10ms fast / 60s slow watchdog window, open-drain RESET/WDPO outputs, -40°C to +125°C operation, and compatibility with bidirectional µP reset pins.

Technical Context

The MAX6324EUT26 implements a dual-window watchdog timer that detects both fast faults (WDI falling edges <10ms apart) and slow faults (no WDI edge >60s), with WDPO pulsed low for 1ms on fault detection. Its internal reset comparator guarantees valid output down to VCC = +1.2V and features ±2.5% accuracy over temperature.

RESET is asserted low when VCC drops below 2.63V or MR is pulled low; deassertion requires VCC >2.63V and MR high for ≥100ms. The open-drain RESET and WDPO outputs support level-shifting across supply domains and direct interfacing with bidirectional µP reset pins like the Motorola 68HC11.

Key Specifications

Pinout & Package

MAX6324EUT26 is housed in a 6-pin SOT23-6 package (JEDEC MO-178AA), footprint-compatible with industry-standard 2.9mm × 1.6mm SOT-23 layouts and reflow-solderable per JEDEC J-STD-020.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6324EUT26, MAX6324EUT29 offers identical watchdog timing but higher reset threshold for 3.3V systems, while TLV809E26DBZR omits watchdog entirely-making it unsuitable for applications requiring min/max timing supervision of µP execution.

Availability

MAX6324EUT26 is available at Aetrix Electronics and suitable for automotive engine control units, industrial PLC controllers, medical infusion pumps, and railway signaling modules requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6324EUT26 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 medical applications.

The MAX6323/MAX6324 family delivers fault-tolerant µP supervision with windowed watchdog capability, targeting safety-critical embedded systems where deterministic reset and execution timing verification are mandatory.

FAQ

What is the exact reset threshold voltage of MAX6324EUT26 and how is it trimmed?

The MAX6324EUT26 has a factory-laser-trimmed reset threshold of 2.63V with ±2.5% accuracy over -40°C to +125°C. This value is fixed per unit and corresponds to the "26" suffix in the part number, referencing the 2.63V nominal threshold in Maxim's Reset Threshold Range table. No external adjustment is possible-the trimming is performed during wafer sort and permanently programmed into the device.

Does MAX6324EUT26 support watchdog timeout configuration via pins or registers?

No, MAX6324EUT26 does not support dynamic watchdog timeout configuration. Its fast timeout (10ms min / 15ms max) and slow timeout (60s min / 90s max) are factory-laser-trimmed and fixed-encoded by the "E" in the part number per Maxim's Watchdog Timeout table. Configuration occurs only at manufacturing; no pins, straps, or registers allow runtime modification of these windows.

Can MAX6324EUT26 drive a reset line directly connected to a 5V-tolerant µP with bidirectional reset pin?

Yes, MAX6324EUT26 can directly interface with bidirectional µP reset pins such as those on the Motorola 68HC11. Its open-drain RESET output allows safe wired-OR connection: a single pullup resistor (e.g., 10kΩ to +3.3V or +5V) enables either the MAX6324EUT26 or the µP to assert reset, satisfying bidirectional control requirements without level-shifting circuitry.

What is the minimum VCC voltage at which MAX6324EUT26 guarantees valid RESET output assertion?

MAX6324EUT26 guarantees valid RESET output assertion down to VCC = +1.2V. Below this voltage, the internal circuitry cannot sink sufficient current to maintain a solid logic-low state on the open-drain RESET pin. This specification ensures deterministic reset behavior during deep brownout conditions before the monitored supply collapses completely.

How does the windowed watchdog in MAX6324EUT26 detect software execution faults?

The MAX6324EUT26 detects software faults using dual-window timing: a fast fault occurs if two WDI falling edges are spaced <10ms apart (indicating runaway loop), and a slow fault occurs if no WDI edge appears within 60s (indicating full stall). Upon detection, WDPO pulses low for 1ms-providing a dedicated, non-reset fault signal that can trigger NMI or MR loopback without disrupting normal reset timing.