Analog Devices Inc./Maxim Integrated MAX6318LHUK26CY+

Overview

MAX6318LHUK26CY+ from Maxim Integrated is a 5-pin SOT23 microprocessor supervisory circuit with active-low push/pull reset output, 2.63V factory-trimmed reset threshold, 140ms minimum reset timeout, and 1.6s typical watchdog timeout. It monitors VCC supply integrity and provides reset assertion during power-up, brownout, or software hang conditions in embedded control systems.

For engineers reviewing the MAX6318LHUK26CY+ datasheet, MAX6318LHUK26CY+ pinout, MAX6318LHUK26CY+ application, or MAX6318LHUK26CY+ equivalent, key selection criteria include guaranteed reset validity down to VCC = 1V, immunity to short negative VCC transients (<4µs at 100mV under VTH), bidirectional reset compatibility (though not implemented in this variant), and AEC-Q100 qualification for automotive-adjacent industrial use.

Technical Context

The MAX6318LHUK26CY+ integrates a precision voltage detector with ±1.5% threshold accuracy at +25°C and ±2.5% over –40°C to +125°C, paired with a digitally trimmed reset timer and independent watchdog timer. Its reset generator asserts active-low RESET when VCC falls below 2.63V or when manual reset (MR) is pulled low - with reset held for exactly 140ms after VCC recovery or MR release.

Unlike bidirectional variants (e.g., MAX6318MH), this part uses a CMOS push/pull output capable of sourcing/sinking ≥500µA at VCC ≥2.7V, eliminating external pullup requirements. The watchdog input (WDI) accepts edge-triggered pulses ≥50ns wide and clears internally if left unconnected, disabling watchdog functionality by default.

Key Specifications

Pinout & Package

MAX6318LHUK26CY+ is housed in a RoHS-compliant 5-pin SOT23 package (package code U5+2A, outline 21-0057), with 0.95mm pitch, 2.9mm × 1.6mm footprint, 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 MAX6318MHUK26CY+, the MAX6318LHUK26CY+ simplifies reset line design by removing bidirectional complexity, while versus TPS3808G125DBVR it adds critical watchdog and MR functionality essential for autonomous recovery in unattended systems.

Availability

MAX6318LHUK26CY+ is available at Aetrix Electronics and suitable for industrial PLC controllers, automotive body control modules, medical infusion pumps, and smart energy meters requiring stable component supply with long-term lifecycle support.

Supply support for MAX6318LHUK26CY+ 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 industrial, automotive, communications, and computing markets.

The MAX6316–MAX6322 family was engineered specifically for robust, low-power microprocessor supervision in space-constrained, thermally demanding applications - emphasizing precision threshold stability, glitch immunity, and flexible reset architecture.

FAQ

What is the exact reset threshold voltage of MAX6318LHUK26CY+?

The MAX6318LHUK26CY+ features a factory-laser-trimmed reset threshold of 2.63V nominal, with tolerance of ±1.5% at +25°C and ±2.5% over the full –40°C to +125°C operating range. This value corresponds to the "26" suffix in the part number per Table 1 of the datasheet.

Does MAX6318LHUK26CY+ include a watchdog timer, and how is it configured?

Yes, MAX6318LHUK26CY+ includes a watchdog timer with a typical timeout of 1.6s. It is enabled by default and cleared on any rising or falling edge at the WDI pin. To disable it, leave WDI unconnected - the internal timer will then self-clear at intervals equal to 7/8 of the watchdog period.

Can MAX6318LHUK26CY+ operate reliably during severe supply transients?

Yes, MAX6318LHUK26CY+ is immune to short negative VCC transients: it will not falsely assert reset for pulses ≤4µs duration when VCC dips up to 100mV below the 2.63V threshold. This allows stable operation in electrically noisy environments without requiring oversized input capacitance.

What is the function of the MR pin on MAX6318LHUK26CY+?

The MR (Manual Reset) pin on MAX6318LHUK26CY+ is an active-low input with internal 52kΩ pullup. Pulling MR low forces a reset that remains asserted for the full 140ms timeout period after MR returns high. It requires no external debouncing and rejects 100ns noise pulses.

Is MAX6318LHUK26CY+ compatible with 1.8V microcontrollers?

No - MAX6318LHUK26CY+ requires VCC between 1.0V and 5.5V but asserts reset only when VCC falls below its fixed 2.63V threshold. For 1.8V systems, a different variant such as MAX6318LHUK18CY+ (1.8V threshold) would be required; the "26" suffix explicitly denotes 2.63V.