Analog Devices Inc./Maxim Integrated MAX6318MHUK46CY+

Overview

MAX6318MHUK46CY+ from Maxim Integrated is a 5-pin SOT23 microprocessor supervisory circuit with bidirectional active-low reset output, 4.63V factory-trimmed reset threshold, 140ms minimum reset timeout, and 1.6s typical watchdog timeout. It monitors VCC supply integrity and μP activity in embedded systems requiring robust brownout detection and Motorola 68HC11-compatible reset signaling.

For engineers reviewing the MAX6318MHUK46CY+ datasheet, MAX6318MHUK46CY+ pinout, MAX6318MHUK46CY+ application, or MAX6318MHUK46CY+ equivalent, key selection criteria include its integrated 4.7kΩ pullup + active P-channel pullup for fast bidirectional reset line rise time, guaranteed reset validity down to VCC = 1V, immunity to sub-4µs negative VCC transients, and AEC-Q100 qualification for automotive-grade reliability.

Technical Context

The MAX6318MHUK46CY+ implements a dual-stage reset generator with voltage monitoring, manual reset input (MR), and watchdog timer (WDI). Its bidirectional RESET output combines a 4.7kΩ passive pullup resistor with an active P-channel FET that engages when RESET rises above 0.65V, enabling reliable low-to-high transitions within two external clock cycles even with >250pF bus capacitance.

Reset assertion occurs on VCC drop below 4.63V (±2.5% over -40°C to +125°C), MR low pulse ≥1.5µs, or WDI inactivity beyond 1.6s. Reset remains asserted for 140ms after VCC recovery, MR release, or watchdog timeout - with propagation delay <240µs at VCC falling at 1mV/µs and VRST–VCC = 100mV.

Key Specifications

Pinout & Package

MAX6318MHUK46CY+ is housed in a RoHS-compliant 5-pin SOT23 package (package code U5+2A, outline 21-0057), measuring 2.9mm × 1.6mm × 1.1mm, with thermal resistance θJA = 255.9°C/W on multilayer PCB.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6318MHUK46CY+, MAX6318MHUK46CT+ offers identical functionality but lacks RoHS compliance, while TPS3808G33DBVR provides lower quiescent current and tighter threshold accuracy at the expense of missing bidirectional reset support and incompatible voltage rating - making neither a drop-in replacement.

Availability

MAX6318MHUK46CY+ is available at Aetrix Electronics and suitable for automotive engine control units, industrial PLC modules, medical infusion pump controllers, smart energy meters, and portable instrumentation requiring stable component supply with AEC-Q100 assurance and long-term lifecycle support.

Supply support for MAX6318MHUK46CY+ 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, communications, and computing markets, with emphasis on high-reliability, low-power, and small-footprint solutions.

The MAX6316–MAX6322 family delivers compact, factory-configured supervisory circuits targeting space-constrained embedded systems needing guaranteed reset behavior, watchdog supervision, and robust noise immunity - especially where bidirectional reset signaling is required.

FAQ

What is the exact reset threshold voltage of MAX6318MHUK46CY+ and how does it vary with temperature?

The MAX6318MHUK46CY+ has a factory-trimmed nominal reset threshold of 4.63V at +25°C, with tolerance of ±2.5% over the full operating range of -40°C to +125°C. Its temperature coefficient is 40ppm/°C, meaning the threshold drifts less than ±11.6mV across the entire temperature span - ensuring consistent brownout detection in automotive and industrial environments where ambient temperature fluctuates widely. This value is confirmed in Table 1 and Electrical Characteristics section of the datasheet.

Does MAX6318MHUK46CY+ support bidirectional reset communication with the Motorola 68HC11 microcontroller?

Yes, MAX6318MHUK46CY+ explicitly supports bidirectional reset communication with the Motorola 68HC11. Its Pin 1 RESET output integrates a 4.7kΩ pullup resistor and an active P-channel FET that enables fast low-to-high transitions (<666ns with 400pF load), allowing the 68HC11 to distinguish between supervisor-initiated and μP-initiated resets by sampling RESET after two clock cycles - a requirement documented in the Bidirectional RESET Output section and Figure 3 of the datasheet.

What is the watchdog timeout period of MAX6318MHUK46CY+ and how is it configured?

The MAX6318MHUK46CY+ features a typical watchdog timeout period of 1.6s, factory-programmed and non-adjustable. This value corresponds to the "Y" suffix in the ordering nomenclature (per Table 3), and is fixed at manufacture - no external components or register writes are needed. The watchdog timer clears on any WDI edge (rising or falling) and asserts reset if no transition occurs within 1.6s, as verified in the Electrical Characteristics table and Selector Guide.

Can MAX6318MHUK46CY+ operate reliably when the supply voltage drops below 2.0V?

Yes, MAX6318MHUK46CY+ guarantees valid reset output behavior down to VCC = 1.0V, as stated in Absolute Maximum Ratings and Electrical Characteristics. Both RESET assertion (low) and deassertion (high) remain functional and specified at VCC ≥ 1.0V - enabling safe operation during deep brownout events common in battery-backed systems. This is confirmed by VOL/VOH specifications tested at VCC ≥ 1.0V and 1.2V, respectively.

Is MAX6318MHUK46CY+ qualified for automotive applications and what standards does it meet?

Yes, MAX6318MHUK46CY+ is AEC-Q100 qualified (Grade 1: -40°C to +125°C), as explicitly noted in the Benefits and Features section and confirmed in Package Information. It meets automotive reliability requirements for temperature cycling, humidity, and ESD robustness - making it suitable for engine control, body electronics, and ADAS subsystems where extended temperature operation and long-term stability are mandatory.