Analog Devices Inc./Maxim Integrated MAX6721UTYDD3

Overview

The MAX6721UTYDD3 from Maxim Integrated is a dual-voltage microprocessor supervisory circuit in 6-pin SOT23 package, monitoring VCC1 (primary supply) and VCC2 (secondary supply) with factory-trimmed reset thresholds of 4.625V and 3.075V respectively, 210ms minimum reset timeout, and integrated watchdog timer with 35s startup/1.12s normal mode. It ensures reliable system reset during power faults in telecom and industrial embedded systems.

For engineers reviewing the MAX6721UTYDD3 datasheet, MAX6721UTYDD3 pinout, MAX6721UTYDD3 application, or MAX6721UTYDD3 equivalent, this page delivers verified electrical parameters, exact pin functions, dual-supply monitoring behavior, watchdog timing architecture, and validated alternative parts for design-in decisions under -40°C to +125°C operating conditions.

Technical Context

The MAX6721UTYDD3 implements dual independent voltage comparators with hysteresis (0.5% typical), guaranteed reset validity down to VCC1 or VCC2 = 0.8V, and a dual-mode watchdog timer: 35s minimum startup period after reset followed by 1.12s minimum normal timeout. Its RST output is push-pull active-low referenced to VCC1.

It features manual-reset input (MR) with internal 50kΩ pullup, watchdog disable via open WDI, and operates with ultra-low supply current - 14µA typical at 3.6V - across the full -40°C to +125°C temperature range. No external components are required for basic supervision functionality.

Key Specifications

Pinout & Package

MAX6721UTYDD3 is housed in a 6-pin SOT23 package (2.9mm × 1.6mm × 1.1mm height), RoHS-compliant and tape-and-reel packaged. Pin 1 is marked with dot; pin numbering follows standard SOT23 counterclockwise layout.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6720UTYDD3 and TPS3808G33DBVR, the MAX6721UTYDD3 uniquely integrates dual-rail supervision with a production-ready dual-mode watchdog - enabling both robust boot-time margin and fast runtime fault response in one 6-pin SOT23 device.

Availability

MAX6721UTYDD3 is available at Aetrix Electronics and suitable for telecom infrastructure, industrial PLCs, and automotive infotainment systems requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for MAX6721UTYDD3 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 demanding industrial, automotive, and communications applications, with emphasis on reliability, integration, and thermal robustness.

The MAX6715A–MAX6729A family delivers ultra-low-voltage, multi-rail supervision for space-constrained embedded systems - engineered specifically for fail-safe power sequencing and watchdog-protected operation in harsh environments.

FAQ

What are the factory-trimmed reset thresholds for MAX6721UTYDD3?

The MAX6721UTYDD3 has factory-trimmed reset thresholds of 4.625V for VCC1 (primary supply) and 3.075V for VCC2 (secondary supply), as indicated by the "T" and "S" suffixes in its ordering code. These values are guaranteed over the full -40°C to +125°C temperature range with ±1.5% tolerance, and include 0.5% hysteresis to prevent chatter near trip points. The MAX6721UTYDD3 does not support adjustable RSTIN or PFI inputs.

Does MAX6721UTYDD3 include a watchdog timer, and how is it configured?

Yes, the MAX6721UTYDD3 includes a dual-mode watchdog timer with a 35s minimum startup period after any reset event (power-up, MR, or watchdog timeout), followed by a 1.12s minimum normal timeout period. Configuration is automatic: WDI must receive a rising or falling edge within the normal timeout window to clear the timer. Leaving WDI unconnected disables the watchdog function entirely, using a 200nA internal current source to detect the open state.

What is the reset output type and drive capability of MAX6721UTYDD3?

The MAX6721UTYDD3 features a push-pull active-low RST output referenced to VCC1. It sources up to 800µA and sinks up to 3.2mA while maintaining VOL ≤ 0.4V at VCC1 ≥ 4.5V. This eliminates the need for an external pullup resistor and allows direct interfacing with µP reset pins - including bidirectional ones when used with a 4.7kΩ series resistor per Maxim's recommended interface.

Can MAX6721UTYDD3 operate reliably during deep supply brownouts?

Yes, the MAX6721UTYDD3 guarantees correct RST output logic state as long as either VCC1 or VCC2 remains above 0.8V - a key feature for controlled shutdown during gradual power loss. Its internal circuitry remains functional down to this level, ensuring deterministic reset assertion even when input rails decay slowly, unlike many supervisors that lose validity below 1.2V or 1.8V.

What package and environmental rating does MAX6721UTYDD3 have?

The MAX6721UTYDD3 is supplied in a lead-free, RoHS-compliant 6-pin SOT23 package (2.9mm × 1.6mm footprint, 1.1mm max height) and is fully specified for operation from -40°C to +125°C. It meets industrial and automotive-grade reliability requirements, with guaranteed performance across this full range - including supply current, reset thresholds, timeout periods, and watchdog timing - without derating or conditional specifications.