Analog Devices Inc./Maxim Integrated MAX6721UTRVD3

Overview

MAX6721UTRVD3 from Maxim Integrated is a dual-voltage microprocessor supervisory IC monitoring VCC1 (primary supply) and VCC2 (secondary supply), with factory-trimmed reset thresholds of 4.625V (VTH1) and 3.075V (VTH2), 210ms minimum reset timeout, watchdog timer (35s startup / 1.12s normal mode), and push-pull active-low RST output. It ensures reliable system reset in telecom power supplies and industrial controllers where dual-rail integrity is critical.

For engineers reviewing the MAX6721UTRVD3 datasheet, MAX6721UTRVD3 pinout, MAX6721UTRVD3 application, or MAX6721UTRVD3 equivalent, key selection criteria include guaranteed reset validity down to VCC1/VCC2 = 0.8V, immunity to sub-µs VCC transients, low 14µA typical supply current at 3.6V, and SOT23-6 package compatibility with space-constrained embedded designs.

Technical Context

The MAX6721UTRVD3 implements dual independent voltage comparators with 20ppm/°C tempco and 0.5% hysteresis referenced to VTH typical, enabling stable threshold detection across -40°C to +125°C. Its internal watchdog uses dual-mode timing: a 35s min startup period after any reset event followed by 1.12s min normal timeout, triggered by WDI edge transitions.

Reset assertion occurs when either VCC1 falls below 4.625V or VCC2 drops below 3.075V, with tRD < 20µs propagation delay. The push-pull RST output drives low to ≤0.4V at 3.2mA sink (VCC1 ≥ 4.5V) and high to ≥0.8×VCC1 at 800µA source, eliminating external pull-up requirements for active-low reset signaling.

Key Specifications

Pinout & Package

MAX6721UTRVD3 is housed in a 6-pin SOT23 package with 1.6mm × 2.9mm footprint and 0.95mm height, compatible with standard reflow soldering processes.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6720UTRVD3, the MAX6721UTRVD3 adds watchdog supervision without altering reset timing or voltage thresholds; versus TPS3808G33DBVR, it integrates dual-rail monitoring and higher drive strength at the cost of 11.5µA higher quiescent current.

Availability

MAX6721UTRVD3 is available at Aetrix Electronics and suitable for telecom infrastructure, industrial automation, and automotive infotainment systems requiring stable component supply with guaranteed long-term availability.

Supply support for MAX6721UTRVD3 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.

The MAX6715A–MAX6729A family delivers ultra-low-voltage supervisory circuits optimized for dual/triple supply monitoring in space-constrained embedded systems with extended temperature requirements.

FAQ

What is the exact reset threshold voltage for VCC1 and VCC2 on the MAX6721UTRVD3?

The MAX6721UTRVD3 has factory-trimmed reset thresholds of 4.625V for VCC1 (primary supply) and 3.075V for VCC2 (secondary supply), specified as minimum values at the falling edge with 0.5% hysteresis. These thresholds are confirmed in the Reset Voltage Threshold Suffix Guide and validated across the full -40°C to +125°C operating range.

Does the MAX6721UTRVD3 include a watchdog timer, and what are its timing characteristics?

Yes, the MAX6721UTRVD3 includes a dual-mode watchdog timer with a 35s minimum startup period after any reset event and a 1.12s minimum normal timeout period. The watchdog is enabled by default and disabled only when the WDI pin is left floating; it monitors for valid edges on WDI and asserts RST if no transition occurs within the timeout window.

What package type and pin count does the MAX6721UTRVD3 use?

The MAX6721UTRVD3 uses a 6-pin SOT23 package (1.6mm × 2.9mm footprint) with pins assigned as RST, GND, MR, VCC2, VCC1, and WDI. This package is RoHS-compliant and supports standard reflow soldering profiles, matching the mechanical form factor of other MAX67xxA series devices in the same pin count.

How does the MAX6721UTRVD3 ensure reliable reset operation during low-voltage conditions?

The MAX6721UTRVD3 guarantees valid reset output logic states down to VCC1 or VCC2 = 0.8V, verified across temperature. Its push-pull RST output drives low to ≤0.4V at 3.2mA (VCC1 ≥ 4.5V) and high to ≥0.8×VCC1, ensuring robust noise margins even during deep brownout conditions without external components.

Can the MAX6721UTRVD3 monitor a third voltage rail, and if not, what are the alternatives?

No, the MAX6721UTRVD3 is a dual-voltage supervisor without RSTIN or PFI inputs; it monitors only VCC1 and VCC2. For triple-voltage monitoring, consider the MAX6723UTRVD3 (which adds RSTIN) or MAX6728UTRVD3 (which adds PFI/PFO), both sharing the same SOT23-6 package and 210ms timeout but differing in auxiliary monitoring capabilities.