Analog Devices Inc./Maxim Integrated MAX6720UTSYD3+T

Overview

MAX6720UTSYD3+T 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, manual reset, or watchdog timeout, and supports power-fail detection. It ensures reliable system boot and brownout recovery in battery-powered telecom and industrial controllers.

For engineers reviewing the MAX6720UTSYD3+T datasheet, MAX6720UTSYD3+T pinout, MAX6720UTSYD3+T application, or MAX6720UTSYD3+T equivalent, key selection criteria include dual-supply monitoring with factory-trimmed thresholds, 210ms reset timeout, push-pull RST output referenced to VCC1, guaranteed reset validity down to VCC1/VCC2 = 0.8V, and integrated watchdog with 35s startup + 1.12s normal mode.

Technical Context

The MAX6720UTSYD3+T implements a dual-threshold voltage monitor (VCC1 at 4.625V, VCC2 at 3.075V) plus a high-impedance RSTIN comparator referenced to a 626mV internal bandgap. Its reset logic combines OR-ed fault conditions - VCC1/VCC2 undervoltage, RSTIN undervoltage, or MR assertion - with a monolithic timeout timer ensuring ≥210ms reset hold time after recovery.

It features a dual-mode watchdog: 35s minimum initial timeout after power-up or reset, transitioning to 1.12s minimum normal timeout after first WDI edge; both modes clear on rising/falling WDI transitions. The push-pull RST output is rail-to-rail referenced to VCC1 and sinks up to 3.2mA at 4.5V.

Key Specifications

Pinout & Package

MAX6720UTSYD3+T is housed in a 6-pin SOT23-6 package (2.9mm × 1.6mm × 1.1mm), RoHS-compliant and lead-free (+T suffix). Pin 1 is marked with a dot; pin numbering follows standard SOT23 counterclockwise orientation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6720UTSFD3+T, the MAX6720UTSYD3+T provides higher VCC1 trip point for robustness in 5V systems; compared with TPS3808G33DBVR, it delivers integrated triple-supply monitoring and push-pull drive without external pullups - reducing component count and improving noise immunity in dense layouts.

Availability

MAX6720UTSYD3+T is available at Aetrix Electronics and suitable for industrial PLC controllers, 5G small cell baseband units, battery-powered network routers, and medical point-of-care monitors requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6720UTSYD3+T 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, communications, and computing applications.

The MAX6715–MAX6729 family delivers ultra-low-voltage, multi-rail supervisory circuits optimized for space-constrained, battery-sensitive, and high-reliability systems where simultaneous monitoring of primary, secondary, and auxiliary supplies is critical.

FAQ

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

The MAX6720UTSYD3+T has a factory-trimmed VCC1 reset threshold of 4.625V (±125mV), corresponding to the 'Y' suffix in the Reset Voltage Threshold Suffix Guide. This value is guaranteed over -40°C to +85°C and ensures reliable detection of 5V rail collapse before downstream logic becomes unstable. The MAX6720UTSYD3+T uses this threshold to initiate reset assertion when VCC1 falls below 4.500V (min) or above 4.750V (max).

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

Yes, the MAX6720UTSYD3+T supports third-voltage monitoring via its RSTIN pin, which references an internal 626mV bandgap. To monitor a custom voltage (e.g., 1.2V), connect a resistor divider between the target rail and GND, with the midpoint fed to RSTIN. The formula is V_{EXT_TH} = 626mV × ((R1 + R2)/R2). The MAX6720UTSYD3+T asserts reset when RSTIN falls below 611mV (min), enabling precise undervoltage detection for core or analog supplies.

What is the function of the MR pin on the MAX6720UTSYD3+T, and does it require external components?

The MR pin on the MAX6720UTSYD3+T is an active-low manual reset input with a built-in 50kΩ pullup resistor to VCC1. Pulling MR low forces an immediate reset assertion for the full 210ms timeout period, then releases automatically. No external pullup or debounce circuitry is needed - a simple momentary switch from MR to GND suffices. The MAX6720UTSYD3+T guarantees MR response within 200ns and rejects <100ns glitches, making it robust in noisy environments.

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

The MAX6720UTSYD3+T features a dual-mode watchdog timer: a 35s minimum startup timeout after power-up or reset, followed by a 1.12s minimum normal timeout after the first valid WDI edge. The timer clears on any rising or falling edge at WDI. This architecture allows complex boot sequences to complete before watchdog enforcement begins. The MAX6720UTSYD3+T requires no firmware changes - simply toggle WDI periodically during normal operation to prevent timeout-induced reset.

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

The MAX6720UTSYD3+T features a push-pull active-low reset output (RST) referenced to VCC1. It can sink up to 3.2mA at 4.5V (VOL ≤ 0.4V) and source up to 800µA (VOH ≥ 0.8×VCC1). This eliminates the need for an external pullup resistor and enables direct connection to microprocessor reset pins. The MAX6720UTSYD3+T maintains valid logic levels even when VCC1 or VCC2 drops to 0.8V, ensuring deterministic reset behavior during brownout conditions.