Analog Devices Inc./Maxim Integrated MAX6720UTSYD3+

Overview

MAX6720UTSYD3+ from Maxim Integrated is a triple-voltage microprocessor supervisory circuit in SOT23-6 package, monitoring VCC1 (4.625V threshold), VCC2 (3.075V threshold), and an externally adjustable RSTIN input (626mV reference). It asserts active-low push-pull reset for ≥210ms after any supply drop, supports manual reset and watchdog timer, and operates from -40°C to +85°C. Used in multivoltage telecom and portable systems requiring reliable power sequencing and brownout protection.

For engineers reviewing the MAX6720UTSYD3+ datasheet, MAX6720UTSYD3+ pinout, MAX6720UTSYD3+ application, or MAX6720UTSYD3+ equivalent, key selection criteria include dual-supply monitoring with factory-trimmed thresholds, 210ms reset timeout, push-pull RST output referenced to VCC1, RSTIN-adjustable third-voltage supervision down to 0.62V, and guaranteed reset validity with VCC1 or VCC2 ≥ 0.8V.

Technical Context

The MAX6720UTSYD3+ integrates three independent voltage monitors: primary (VCC1), secondary (VCC2), and auxiliary (RSTIN), each with dedicated comparators and hysteresis. Its reset logic combines ORed fault detection across all inputs and enforces a fixed 210ms minimum timeout via internal timer after recovery.

This device implements a dual-mode watchdog: 35s startup period after reset, then 1.12s normal timeout, triggered by WDI edge transitions. All reset outputs are push-pull, referenced to VCC1, and guaranteed functional down to VCC1 or VCC2 = 0.8V - critical for low-voltage battery-operated systems.

Key Specifications

Pinout & Package

MAX6720UTSYD3+ uses a 6-pin SOT23-6 package with gull-wing leads, 1.27mm pitch, and JEDEC MO-178AC footprint. Pin 1 is marked with dot; pin order follows standard SOT23 orientation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6720UTSVD3+, the MAX6720UTSYD3+ provides higher VCC1 threshold for later reset assertion on 4.8V rails, while TPS3808G33DBVR offers lower unit cost but requires external components to match triple-supply functionality - making MAX6720UTSYD3+ optimal for compact, integrated multivoltage supervision.

Availability

MAX6720UTSYD3+ is available at Aetrix Electronics and suitable for telecom infrastructure, portable medical devices, and industrial controllers requiring stable component supply, long-term lifecycle support, and guaranteed lead-free compliance.

Supply support for MAX6720UTSYD3+ 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 ultra-low-voltage, multirail supervisory functions in miniature SOT23 packages - engineered specifically for space-constrained, battery-sensitive systems needing robust power-fail detection and reset control.

FAQ

What is the exact reset threshold voltage for VCC1 on the MAX6720UTSYD3+?

The MAX6720UTSYD3+ has a factory-trimmed VCC1 reset threshold of 4.625V, with a tolerance of ±125mV (min 4.500V, max 4.750V) over temperature. This value is encoded in the "Y" suffix per Maxim's Reset Voltage Threshold Suffix Guide and is verified across the full -40°C to +85°C operating range. The MAX6720UTSYD3+ uses this precise threshold to detect brownout on 4.8V system rails before critical logic fails.

Does the MAX6720UTSYD3+ support monitoring a third voltage, and how is it configured?

Yes, the MAX6720UTSYD3+ supports third-voltage monitoring via its RSTIN pin, which references an internal 626mV bandgap. To monitor a custom voltage (e.g., 1.2V core rail), connect an external resistor divider between that rail and ground, with the midpoint fed to RSTIN. The divider ratio sets the trip point: V_trip = 626mV × (R1 + R2)/R2. The MAX6720UTSYD3+ asserts reset when RSTIN falls below 626mV, enabling flexible triple-supply supervision.

What is the function of the MR pin on the MAX6720UTSYD3+, and what are its electrical requirements?

The MR (manual reset) pin on the MAX6720UTSYD3+ is an active-low input with a 50kΩ internal pullup to VCC1. Pulling MR ≤ 0.3 × VCC1 for ≥1µs forces an immediate reset assertion, held for the full 210ms timeout after MR returns high. MR accepts TTL/CMOS logic levels and tolerates noise due to 100ns glitch rejection. If unused, MR may be left floating or tied to VCC1; no external components are required for basic operation of the MAX6720UTSYD3+.

How does the watchdog timer operate on the MAX6720UTSYD3+, and what are its timing modes?

The MAX6720UTSYD3+ implements a dual-mode watchdog timer: after any reset event (power-up, MR, or fault), it enters a 35s minimum startup mode to allow full system boot; then switches to 1.12s minimum normal mode upon first valid WDI edge. The watchdog resets the MAX6720UTSYD3+ if WDI remains static beyond the active timeout. This architecture prevents false triggers during boot while ensuring rapid response to software hangs during runtime operation of the MAX6720UTSYD3+.

Is the reset output of the MAX6720UTSYD3+ push-pull or open-drain, and what are its drive capabilities?

The MAX6720UTSYD3+ 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 connection to µP reset pins. Unlike open-drain variants, the MAX6720UTSYD3+ guarantees defined logic states during power ramp-up and brownout - critical for deterministic reset behavior in the MAX6720UTSYD3+.