Analog Devices Inc./Maxim Integrated MAX6324CUT29

Overview

MAX6324CUT29 from Maxim Integrated is a microprocessor supervisory circuit with windowed (min/max) watchdog, open-drain RESET output, and factory-trimmed 3.00V ±2.5% reset threshold. It monitors VCC down to +1.2V, asserts RESET for ≥100ms after recovery, and delivers 1ms WDPO fault pulses on fast/slow watchdog timeouts. Used in automotive engine control units to detect firmware hangs during cold-cranking.

For engineers reviewing the MAX6324CUT29 datasheet, MAX6324CUT29 pinout, MAX6324CUT29 application, or MAX6324CUT29 equivalent, key selection criteria include its 3.00V reset threshold accuracy, 29ms/450ms dual watchdog timeout window (CUT variant), open-drain RESET compatibility with bidirectional µP reset pins, and guaranteed operation at -40°C to +125°C.

Technical Context

The MAX6324CUT29 implements a laser-trimmed windowed watchdog that detects both early (faster than 29ms) and late (slower than 450ms) falling edges on WDI. Its internal comparator guarantees valid RESET assertion even as VCC decays to +1.2V, enabling reliable brownout detection in automotive battery-sag scenarios.

RESET is open-drain with 0.4V max VOL at 1.2mA sink current, requiring external pullup; WDPO is also open-drain, pulsed low for 1ms upon fault detection. The device uses BiCMOS process (1371 transistors) and features debounced MR input with 1µs minimum pulse width and 100ns glitch immunity.

Key Specifications

Pinout & Package

MAX6324CUT29 is housed in a 6-pin SOT23-6 package (JEDEC MO-178AA), 2.9mm × 1.6mm × 1.1mm, with gull-wing leads and exposed pad not present.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6324CUT29, MAX6324CUT31 offers higher reset threshold for tighter +3.3V regulation, while TPS3808G33DBVR provides lower-cost basic supervision but lacks windowed watchdog functionality essential for detecting subtle firmware anomalies.

Availability

MAX6324CUT29 is available at Aetrix Electronics and suitable for automotive engine control, industrial PLCs, and medical infusion pumps requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6324CUT29 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 high-performance analog and mixed-signal ICs for demanding industrial, automotive, and medical applications.

The MAX6324CUT29 belongs to the MAX6323/MAX6324 family of microprocessor supervisory circuits engineered specifically for safety-critical embedded systems requiring robust power monitoring and advanced windowed watchdog functionality.

FAQ

What is the exact reset threshold voltage of MAX6324CUT29 and how is it trimmed?

The MAX6324CUT29 has a nominal reset threshold of 3.00V with ±2.5% accuracy over -40°C to +125°C. This value is achieved through factory laser trimming of internal resistors, as confirmed in the Reset Threshold Range table (page 10 of the datasheet). The '29' suffix explicitly denotes the 3.00V variant, and typical measured value is 3.08V at +25°C.

Does MAX6324CUT29 support true windowed watchdog operation, and what are its timeout values?

Yes, MAX6324CUT29 implements a true min/max (windowed) watchdog. Its 'CUT' suffix specifies a fast timeout window of 29ms (min) to 39ms (max) and a slow timeout window of 300ms (min) to 450ms (max), measured from falling edge to falling edge on WDI. These values are laser-trimmed and guaranteed across temperature.

Can MAX6324CUT29's RESET output interface directly with a microcontroller having a bidirectional reset pin?

Yes, MAX6324CUT29's open-drain RESET output is explicitly designed for this use case. As stated in Applications Information (page 8), it interfaces seamlessly with µPs like the Motorola 68HC11 by sharing a single pullup resistor - allowing either the MAX6324CUT29 or the µP to assert reset on the same net.

What is the minimum VCC voltage at which MAX6324CUT29 guarantees valid RESET assertion?

MAX6324CUT29 guarantees valid RESET output down to VCC = +1.2V, as specified in the General Description and Electrical Characteristics tables. Below this voltage, the internal circuitry cannot sink sufficient current to maintain a logic-low RESET, making +1.2V the functional lower limit for reliable brownout detection.

How does the manual reset (MR) input behave on MAX6324CUT29, and what are its timing requirements?

The MR input on MAX6324CUT29 is active-low, internally pulled up to VCC, and debounced. It requires a minimum 1µs low pulse to assert RESET, and after release, RESET remains asserted for ≥100ms. Glitch immunity is rated at 100ns, and a 0.1µF capacitor to ground adds noise immunity - all confirmed in Pin Description and Applications Information sections.