Analog Devices Inc./Maxim Integrated MAX6718UKZWD3+

Overview

MAX6718UKZWD3+ from Maxim Integrated is a dual-voltage microprocessor supervisory circuit in 5-pin SOT23 package, monitoring VCC1 (1.62V threshold) and VCC2 (2.313V threshold) with 210ms reset timeout, push-pull active-low RST output, manual reset input, and guaranteed reset validity down to 0.8V on either supply - used in multivoltage embedded systems requiring reliable power-on reset and brownout detection.

For engineers reviewing the MAX6718UKZWD3+ datasheet, MAX6718UKZWD3+ pinout, MAX6718UKZWD3+ application, or MAX6718UKZWD3+ equivalent, key selection criteria include dual-supply threshold accuracy (±1.5% over temperature), ultra-low 14µA typical supply current at 3.6V, immunity to sub-20µs VCC transients, and compatibility with 1.8V/0.9V core-I/O rail architectures in portable and industrial equipment.

Technical Context

The MAX6718UKZWD3+ integrates two independent voltage comparators with factory-trimmed thresholds (VTH1 = 1.62V, VTH2 = 2.313V), a 210ms minimum reset timeout timer, and push-pull RST output referenced to VCC1. It asserts reset when either VCC1 falls below 1.62V or VCC2 drops below 2.313V, maintaining reset for ≥210ms after both supplies recover.

It features an internal 50kΩ pullup on MR, supports manual reset pulse widths ≥1µs, and guarantees valid reset logic state as long as VCC1 or VCC2 remains ≥0.8V - enabling robust operation during deep brownout conditions without external supervision.

Key Specifications

Pinout & Package

MAX6718UKZWD3+ uses a 5-pin SOT23 package (2.9mm × 1.6mm × 1.1mm) with gull-wing leads, RoHS-compliant lead-free finish (+T suffix), and thermal pad not electrically connected.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-voltage supervisory applications.

Compared with MAX6718UKZWD2+, the MAX6718UKZWD3+ provides 16× longer reset hold time for complex power sequencing; versus TPS3808G16DBVR, it delivers integrated dual-rail monitoring at higher quiescent current but eliminates BOM count and layout area for a second supervisor.

Availability

MAX6718UKZWD3+ is available at Aetrix Electronics and suitable for industrial PLCs, portable medical monitors, telecom line cards, and smart energy meters requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6718UKZWD3+ 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, and communications markets, with expertise in power management and reliability-critical functions.

The MAX6715–MAX6729 product line delivers ultra-low-voltage, dual/triple-supply supervisory circuits optimized for space-constrained, battery-sensitive, and high-reliability embedded systems demanding accurate brownout detection and deterministic reset behavior.

FAQ

What is the exact reset threshold voltage for VCC1 on the MAX6718UKZWD3+?

The MAX6718UKZWD3+ has a factory-trimmed VCC1 reset threshold of 1.62V (typical), with guaranteed limits of 1.575V (min) and 1.665V (max) over -40°C to +85°C. This value is encoded in the "Z" suffix per Maxim's Reset Voltage Threshold Suffix Guide and applies specifically to the MAX6718UKZWD3+ - not the broader MAX6715–MAX6729 family.

Does the MAX6718UKZWD3+ support monitoring a third voltage rail?

No, the MAX6718UKZWD3+ is a dual-voltage supervisor and does not include RSTIN or PFI inputs. Only MAX6719–MAX6729 variants provide triple-voltage monitoring capability. The MAX6718UKZWD3+ monitors only VCC1 and VCC2, as confirmed by its position in the Selector Guide and pin configuration (5-pin SOT23 with no RSTIN/PFI pin).

What is the function of Pin 3 (MR) on the MAX6718UKZWD3+?

Pin 3 is the active-low Manual Reset input (MR) with an internal 50kΩ pullup to VCC1. Driving MR below 0.3×VCC1 asserts the RST output for the full 210ms timeout period, even if VCC1/VCC2 remain valid. It requires no external components and supports direct connection to a momentary switch to GND for field service reset - a feature confirmed in the Pin Description table and Applications Information section.

Is the reset output of the MAX6718UKZWD3+ open-drain or push-pull?

The MAX6718UKZWD3+ features a push-pull active-low RST output (Pin 1), as indicated by the "U" in the ordering code (per Selector Guide: MAX6718 = push-pull single RST). This allows direct driving of CMOS inputs without an external pullup resistor, with VOH ≥ 0.8×VCC1 and VOL ≤ 0.4V at 3.2mA sink current - verified in the Electrical Characteristics table under "RST Output HIGH/LOW".

What is the minimum VCC voltage at which the MAX6718UKZWD3+ guarantees correct reset logic state?

The MAX6718UKZWD3+ guarantees valid reset output logic (high or low as appropriate) as long as either VCC1 or VCC2 remains ≥0.8V, per the Absolute Maximum Ratings and Detailed Description sections. This specification enables reliable operation during deep brownout conditions where one supply collapses while the other sustains minimal functionality - a key differentiator versus standard supervisors.