Analog Devices Inc./Maxim Integrated MAX6318LHUK27CY+

Overview

The MAX6318LHUK27CY+ from Maxim Integrated is a 5-pin SOT23 microprocessor supervisory circuit with active-low push/pull reset output, manual reset input (MR), and watchdog timer (WDI). It features a factory-trimmed 2.7V reset threshold (±2.5% over -40°C to +125°C), 140ms minimum reset timeout, and 1.6s typical watchdog timeout. It is AEC-Q100 qualified and used in embedded control systems requiring reliable power-on/brownout reset and software fault recovery.

For engineers reviewing the MAX6318LHUK27CY+ datasheet, MAX6318LHUK27CY+ pinout, MAX6318LHUK27CY+ application, or MAX6318LHUK27CY+ equivalent, key selection criteria include its 2.7V reset threshold accuracy, guaranteed reset validity down to VCC = 1V, bidirectional compatibility support (though not implemented in this variant), and absence of manual reset-enabling simplified system-level reset coordination in space-constrained portable equipment.

Technical Context

The MAX6318LHUK27CY+ integrates a precision voltage detector, reset generator with fixed 140ms timeout, and watchdog timer with 1.6s typical period. Its reset output is active-low push/pull, sourcing/sinking current without external components, and remains valid down to VCC = 1V. The device asserts reset on VCC drop below 2.7V, on WDI timeout, or-unlike MAX6318MH/MAX6319 variants-does not support manual reset (MR pin is unused).

It uses a factory-laser-trimmed resistor divider for threshold accuracy and includes immunity to short negative VCC transients (<4µs at 100mV under VTH). The watchdog input (WDI) detects rising/falling edges ≥50ns and clears internally if left unconnected, disabling watchdog functionality by default.

Key Specifications

Pinout & Package

MAX6318LHUK27CY+ is housed in a RoHS-compliant 5-pin SOT23 package (package code U5+2A, outline 21-0057), with 0.95mm pitch and thermal resistance θJA = 255.9°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 MAX6318MHUK27CY+, MAX6318LHUK27CY+ delivers identical threshold and timing but replaces bidirectional drive with simpler push/pull output-reducing complexity in single-MCU systems. Against MAX6319LHUK27CY+, it omits MR functionality, lowering cost and layout overhead where hardware reset is not required.

Availability

MAX6318LHUK27CY+ is available at Aetrix Electronics and suitable for portable/battery-powered equipment, embedded control systems, and automotive body electronics requiring stable component supply, AEC-Q100 compliance, and long-term lifecycle support.

Supply support for MAX6318LHUK27CY+ 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 power, sensing, and interface applications in industrial, automotive, and computing markets.

The MAX6316–MAX6322 family was developed to deliver highly accurate, low-power, and AEC-Q100-qualified supervisory functions in miniature SOT23 packages for space- and reliability-critical embedded systems.

FAQ

What is the reset threshold voltage of the MAX6318LHUK27CY+?

The MAX6318LHUK27CY+ has a factory-trimmed nominal reset threshold of 2.7V, with guaranteed tolerance of ±2.5% over the full operating temperature range (-40°C to +125°C). This value is laser-trimmed during manufacturing and does not require external calibration. The threshold is referenced to VCC and remains stable across voltage and temperature variations, making it suitable for 2.8V–3.0V supply rails in portable and automotive applications.

Does the MAX6318LHUK27CY+ support manual reset functionality?

No, the MAX6318LHUK27CY+ does not support manual reset. Pin 4 is NC (no connect), and the MR input is not implemented in this variant. Unlike the MAX6319LHUK27CY+, which includes an active-low manual reset input, the MAX6318LHUK27CY+ relies solely on VCC monitoring and watchdog timeout for reset assertion. This simplifies design where hardware-initiated reset is unnecessary.

What is the watchdog timeout period for the MAX6318LHUK27CY+?

The MAX6318LHUK27CY+ features a typical watchdog timeout period of 1.6 seconds, corresponding to the "Y" suffix in its ordering code. This value is factory-programmed and specified at TA = +25°C, with variation bounded by process and temperature. The watchdog timer clears on any WDI edge (≥50ns) and resets automatically when left unconnected, providing flexible fault-monitoring granularity for mid-speed firmware loops.

Is the MAX6318LHUK27CY+ compatible with bidirectional reset microcontrollers like the 68HC11?

No, the MAX6318LHUK27CY+ is not compatible with bidirectional reset MCUs. It provides an active-low push/pull RESET output (pin 1), not a bidirectional or open-drain structure. For 68HC11 or similar processors requiring bidirectional reset signaling, the MAX6318MHUK27CY+-which integrates an active pullup FET and 4.7kΩ resistor-is the appropriate variant within the same family.

What package type and footprint does the MAX6318LHUK27CY+ use?

The MAX6318LHUK27CY+ is packaged in a 5-pin SOT23 case (package code U5+2A, outline 21-0057), measuring 2.9mm × 1.6mm with 0.95mm lead pitch. It uses standard JEDEC SOT23 land pattern 90-0174 and supports both leaded and lead-free reflow soldering (peak 260°C). The small footprint enables high-density placement in portable and automotive modules where board space is constrained.