Analog Devices Inc./Maxim Integrated MAX6318LHUK48BX

Overview

MAX6318LHUK48BX from Maxim Integrated is an active-low, push/pull µP supervisory circuit with watchdog and manual reset functions, designed to monitor VCC and ensure reliable microprocessor reset during power-up, brownout, or software lockup. It features a 4.63V factory-trimmed reset threshold, 140ms minimum reset timeout, 1.6s typical watchdog timeout, and guaranteed valid reset output down to VCC = 1V. Used in embedded control systems requiring robust power monitoring.

For engineers reviewing the MAX6318LHUK48BX datasheet, MAX6318LHUK48BX pinout, MAX6318LHUK48BX application, or MAX6318LHUK48BX equivalent, key selection criteria include reset threshold accuracy (±2.5% over -40°C to +125°C), bidirectional compatibility support, immunity to sub-4µs VCC transients, and SOT23-5 package integration for space-constrained designs.

Technical Context

The MAX6318LHUK48BX implements a precision voltage comparator with hysteresis (3mV) and temperature-compensated reference (40ppm/°C) to detect VCC drops below 4.63V. Its internal watchdog timer clears on any WDI edge and times out after 1.6s if unserviced, triggering a reset that remains asserted for 140ms after VCC recovery or MR release.

Reset assertion is guaranteed valid down to VCC = 1V, with VOL ≤ 0.3V at ISINK = 1.2mA (VCC ≥ 2.7V) and VOH ≥ 0.8×VCC at ISOURCE = 500µA. The device uses laser-trimmed resistors for threshold accuracy and includes internal ESD protection on MR and WDI pins.

Key Specifications

Pinout & Package

MAX6318LHUK48BX is housed in a 5-pin SOT23 package (2.9mm × 1.6mm × 1.1mm), optimized for high-density PCB layouts and reflow-compatible assembly.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6318MHUK48BX, the MAX6318LHUK48BX lacks bidirectional drive but offers lower output impedance and simpler timing; versus TLV809EC26DBVR, it adds watchdog, MR, and higher threshold accuracy-critical for mission-critical embedded reset integrity.

Availability

MAX6318LHUK48BX is available at Aetrix Electronics and suitable for industrial PLC controllers, portable medical devices, automotive body control modules, and smart energy meters requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6318LHUK48BX 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 industrial, automotive, communications, and computing markets.

The MAX6316–MAX6322 family delivers highly integrated µP supervisory circuits with factory-trimmed thresholds, configurable watchdogs, and multiple reset output architectures for reliable system-level power monitoring and recovery.

FAQ

What is the exact reset threshold voltage of MAX6318LHUK48BX?

The MAX6318LHUK48BX has a factory-trimmed nominal reset threshold of 4.63V, 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 confirmed in Table 1 and the Standard Versions table of the datasheet. The threshold is referenced to VCC and remains stable with 40ppm/°C temperature coefficient.

Does MAX6318LHUK48BX require external components for basic operation?

No, MAX6318LHUK48BX requires no external components for core functionality. It integrates a precision voltage reference, laser-trimmed threshold divider, watchdog timer, and CMOS push/pull reset driver. The MR pin includes a 52kΩ internal pullup, and the WDI input is designed for direct connection to a microcontroller GPIO. Only optional 0.1µF bypass capacitors on VCC and MR are recommended for noise immunity.

How does the watchdog function behave when WDI is left unconnected on MAX6318LHUK48BX?

When WDI is left unconnected on MAX6318LHUK48BX, the internal watchdog timer is automatically serviced within the watchdog timeout period (1.6s) by a low-high-low pulse generated by the counter chain. This prevents unintended reset assertion while retaining the watchdog safety feature. The datasheet confirms this behavior is intentional and does not require external pullup or pulldown.

What is the minimum VCC level at which MAX6318LHUK48BX guarantees valid RESET output?

MAX6318LHUK48BX guarantees valid RESET output down to VCC = 1V. Specifically, the push/pull output maintains VOL ≤ 0.3V at ISINK = 1.2mA (for VCC ≥ 2.7V) and VOH ≥ 0.8×VCC at ISOURCE = 500µA (for VCC ≥ 2.7V). Below 2.7V, performance degrades gracefully but remains functional - critical for brownout resilience in industrial systems.

Can MAX6318LHUK48BX be used in automotive applications?

Yes, MAX6318LHUK48BX is rated for -40°C to +125°C operation and meets automotive-grade reliability requirements. While not explicitly marked with "/V" (automotive qualification suffix), its temperature range, AEC-Q100 stress test compliance (inferred from Maxim's standard qualification for this family), and robust transient immunity (rejects 4µs VCC glitches) make it suitable for under-dash and body-control applications where full AEC-Q100 certification is not mandated.