Analog Devices Inc./Maxim Integrated MAX6720UTTGD3

Overview

MAX6720UTTGD3 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 (626.5mV reference). It asserts active-low push-pull reset for ≥210ms after any supply drop, manual reset, or watchdog timeout, and supports power-fail detection. Used in multivoltage embedded systems requiring reliable brownout and startup supervision.

For engineers reviewing the MAX6720UTTGD3 datasheet, MAX6720UTTGD3 pinout, MAX6720UTTGD3 application, or MAX6720UTTGD3 equivalent, key selection criteria include dual-supply threshold accuracy (±1.5% over temperature), guaranteed reset validity down to VCC1/VCC2 = 0.8V, 14µA typical supply current at 3.6V, and integrated watchdog with 35s startup + 1.12s normal timeout.

Technical Context

The MAX6720UTTGD3 implements a dual-threshold voltage monitor with factory-trimmed VTH1 = 4.625V (±1.5%) and VTH2 = 3.075V (±1.5%), plus an auxiliary RSTIN comparator referenced to a 626.5mV internal bandgap. Its reset logic combines OR-ed fault conditions (VCC1/VCC2 undervoltage, RSTIN low, MR low) with a programmable 210ms minimum timeout timer.

It features push-pull RST output referenced to VCC1, manual reset input with 50kΩ internal pullup, and a dual-mode watchdog: 35s min initial period after reset, transitioning to 1.12s min normal timeout upon first WDI edge. Power-fail functionality is not included in this variant (per Selector Guide).

Key Specifications

Pinout & Package

Package: 6-pin SOT23-6, surface-mount, 1.6mm × 2.9mm footprint, 1.1mm height.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6720UTTGD3, the MAX6720UTTGD2-T offers identical supervision architecture but reduced timeout, while TPS3808G33DBVR provides lower-cost single-rail supervision at the expense of triple-voltage integration and RSTIN flexibility.

Availability

MAX6720UTTGD3 is available at Aetrix Electronics and suitable for industrial PLC controllers, network router power management, medical diagnostic handhelds, and automotive infotainment modules requiring stable component supply and guaranteed -40°C to +85°C operation.

Supply support for MAX6720UTTGD3 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 power, sensing, and connectivity applications, with emphasis on high-reliability industrial and automotive solutions.

The MAX6715–MAX6729 family delivers ultra-low-voltage, multirail supervisory circuits targeting space-constrained embedded systems needing coordinated reset across primary, secondary, and auxiliary power domains.

FAQ

What is the exact reset threshold voltage for VCC1 on the MAX6720UTTGD3?

The MAX6720UTTGD3 has a factory-trimmed VCC1 reset threshold of 4.625V, with ±1.5% tolerance over the full -40°C to +85°C temperature range. This value is confirmed in the Reset Voltage Threshold Suffix Guide where 'T' corresponds to 4.625V for VTH1. The threshold is referenced to an internal bandgap and remains stable with supply voltage variations, making it suitable for precise 5V rail supervision in the MAX6720UTTGD3.

Does the MAX6720UTTGD3 support watchdog functionality?

Yes, the MAX6720UTTGD3 includes a dual-mode watchdog timer as specified in the Selector Guide. It provides a 35s minimum initial timeout period after power-up or reset, followed by a 1.12s minimum normal timeout period triggered by the first valid edge on the WDI pin. The watchdog monitors processor activity and asserts the RST output if WDI remains static beyond the timeout, ensuring reliable fault detection in the MAX6720UTTGD3.

What is the function of Pin 6 (RSTIN) on the MAX6720UTTGD3?

Pin 6 (RSTIN) on the MAX6720UTTGD3 is a high-impedance auxiliary reset input with a fixed 626.5mV internal reference voltage. When the voltage at RSTIN falls below this threshold, the device asserts the RST output. Users configure the monitored voltage level using an external resistor divider, enabling supervision of a third supply as low as 0.62V. This feature is integral to the triple-voltage supervision capability of the MAX6720UTTGD3.

Is the MAX6720UTTGD3 compatible with both push-pull and open-drain reset configurations?

The MAX6720UTTGD3 is configured exclusively with a push-pull RST output, as indicated by the 'U' in its ordering code and confirmed in the Selector Guide. It does not support open-drain operation. The RST pin actively drives high to 0.8×VCC1 and low to ≤0.4V (at 3.2mA sink), eliminating the need for an external pullup resistor. This push-pull configuration is a fixed characteristic of the MAX6720UTTGD3 variant.

What is the minimum operating voltage guarantee for reset validity in the MAX6720UTTGD3?

The MAX6720UTTGD3 guarantees valid reset output logic state down to VCC1 = 0.8V or VCC2 = 0.8V, as explicitly stated in the datasheet's "Guaranteed Reset Valid Down to VCC1 or VCC2 = 0.8V" feature and confirmed in Absolute Maximum Ratings. This ensures deterministic reset behavior during severe brownout conditions, a critical reliability feature for the MAX6720UTTGD3 in automotive and industrial applications.