Analog Devices Inc./Maxim Integrated MAX6724UTZWD3+

Overview

MAX6724UTZWD3+ from Maxim Integrated is a triple-voltage microprocessor supervisory circuit in 6-pin SOT23 package, monitoring VCC1 (primary), VCC2 (secondary), and RSTIN (auxiliary) supply rails with factory-trimmed thresholds of 3.075V (VTH1), 2.925V (VTH2), and 626.5mV reference for RSTIN. It provides push-pull active-low reset output (RST), manual reset input (MR), and watchdog timer with 35s startup/1.12s normal timeout. Used in multivoltage embedded systems requiring reliable power-up sequencing and brownout detection.

For engineers reviewing the MAX6724UTZWD3+ datasheet, MAX6724UTZWD3+ pinout, MAX6724UTZWD3+ application, or MAX6724UTZWD3+ equivalent, key selection criteria include its triple-supply monitoring capability, guaranteed reset validity down to VCC1/VCC2 = 0.8V, push-pull RST output referenced to VCC1, 210ms (min) reset timeout, and integrated watchdog with dual-mode timing - critical for telecom, industrial, and battery-operated equipment where deterministic fault recovery is mandatory.

Technical Context

The MAX6724UTZWD3+ implements independent voltage comparators for VCC1, VCC2, and RSTIN, each with ±0.5% hysteresis and 20ppm/°C tempco. Its reset logic asserts RST low when any monitored rail falls below its threshold and holds it low for ≥210ms after all rails recover - enforced by an internal timeout counter.

It integrates a dual-mode watchdog: 35s minimum initial timeout after power-on/manual reset, transitioning to 1.12s normal mode upon first WDI edge detection. The MR input features 50kΩ internal pullup and 1µs minimum pulse width support, while RSTIN accepts externally scaled voltages via resistor divider with 25nA max input current.

Key Specifications

Pinout & Package

MAX6724UTZWD3+ uses a 6-pin SOT23-6 package (2.9mm × 1.6mm × 1.1mm height) with gull-wing leads, RoHS-compliant and lead-free (+T suffix).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6724UTZWD3+, MAX6723UTZWD3+ offers identical monitoring and timing but requires external pullup for RST, while TPS3808G33DBVR reduces supply current by 82% but sacrifices RSTIN flexibility and watchdog functionality - making MAX6724UTZWD3+ optimal for systems needing push-pull drive, triple-rail coverage, and robust fault recovery.

Availability

MAX6724UTZWD3+ is available at Aetrix Electronics and suitable for telecom infrastructure, industrial control, and portable medical equipment requiring stable component supply, long-term lifecycle support, and guaranteed lead-free compliance.

Supply support for MAX6724UTZWD3+ 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, mixed-signal, and power management ICs for demanding industrial, automotive, and communications applications.

The MAX6715–MAX6729 family delivers compact, ultra-low-voltage supervisory circuits targeting multirail embedded systems where space, power, and deterministic reset behavior are critical design constraints.

FAQ

What is the exact reset timeout period for MAX6724UTZWD3+?

The MAX6724UTZWD3+ has a minimum reset timeout period of 210ms, specified by the 'D3' suffix in its part number. This value is guaranteed over the full -40°C to +85°C operating temperature range and ensures sufficient hold time for microprocessor initialization before release. Typical timeout is 210ms, with maximum values up to 280ms under worst-case conditions per datasheet Electrical Characteristics table.

Does MAX6724UTZWD3+ support monitoring a third voltage rail?

Yes, MAX6724UTZWD3+ supports third-rail monitoring via its RSTIN pin, which compares the applied voltage against an internal 626.5mV reference. By connecting an external resistor divider between the target supply and ground, users can scale any voltage down to match this reference - enabling precise supervision of auxiliary rails such as 1.2V cores, 5V analog supplies, or battery backup voltages.

What is the function of the MR pin on MAX6724UTZWD3+?

The MR (Manual Reset) pin on MAX6724UTZWD3+ is an active-low input with internal 50kΩ pullup to VCC1. Pulling MR low forces an immediate reset assertion on the RST output, which remains active for the full 210ms timeout period after MR returns high. This allows hardware-initiated resets for maintenance, emergency stop, or test modes without requiring µP intervention.

Can MAX6724UTZWD3+ operate with VCC1 below 1.8V?

MAX6724UTZWD3+ is guaranteed to assert valid reset logic states when either VCC1 or VCC2 remains above 0.8V, per Absolute Maximum Ratings and Detailed Description sections. While VCC1 nominal range starts at 1.8V, the device maintains correct reset output behavior down to 0.8V - enabling use in deep brownout scenarios where other supervisors would fail silently.

How does the watchdog timer in MAX6724UTZWD3+ behave after power-up?

After power-up or any reset event, MAX6724UTZWD3+ enters a 35s minimum initial watchdog mode. Upon detecting the first valid edge on WDI, it transitions to 1.12s normal timeout mode. This dual-mode architecture prevents false timeouts during lengthy boot sequences while ensuring rapid fault detection once the system is operational - a key differentiator versus single-mode watchdogs.