Analog Devices Inc./Maxim Integrated MAX6720AUTWGD3+T

Overview

MAX6720AUTWGD3+T from Maxim Integrated is a triple-voltage microprocessor supervisory IC monitoring VCC1 (primary), VCC2 (secondary), and RSTIN (auxiliary) supply rails. It asserts an active-low push-pull reset output when any monitored voltage falls below its factory-trimmed threshold (VTH1 = 4.625 V, VTH2 = 3.075 V, VRSTIN = 626.5 mV), maintains reset for 210 ms (min), and operates down to VCC = 0.8 V. It supports watchdog timer functionality with 35 s startup and 1.12 s normal timeout, targeting multivoltage embedded systems requiring reliable power sequencing and fault detection.

For engineers reviewing the MAX6720AUTWGD3+T datasheet, MAX6720AUTWGD3+T pinout, MAX6720AUTWGD3+T application, or MAX6720AUTWGD3+T equivalent, key selection considerations include its dual-supply monitoring capability with adjustable third-input threshold, guaranteed reset validity at ultra-low VCC, push-pull RST output referenced to VCC1, and integrated watchdog with long/short dual-mode timing-critical for battery-operated and telecom equipment where brownout resilience and software supervision are mandatory.

Technical Context

The MAX6720AUTWGD3+T implements independent voltage comparators for VCC1 (1.58–4.63 V range), VCC2 (0.79–3.08 V), and RSTIN (626.5 mV internal reference), each with 20 ppm/°C tempco and 0.5% hysteresis. Its reset logic combines ORed fault conditions (VCC1/VCC2 undervoltage, RSTIN low, MR assertion) and enforces a minimum 210 ms reset timeout after all thresholds are reasserted.

This device integrates a dual-mode watchdog timer: a 35 s (min) initial timeout after power-up/manual reset enables full system boot, followed by a 1.12 s (min) normal mode triggered by the first WDI edge; it also features a manual reset input with 50 kΩ internal pullup and 1 µs minimum pulse width, plus immunity to sub-20 µs VCC transients exceeding 100 mV overdrive.

Key Specifications

Pinout & Package

MAX6720AUTWGD3+T is housed in a 6-pin SOT23-6 package (2.9 mm × 1.6 mm × 1.1 mm), optimized for space-constrained PCB layouts in portable and telecom equipment. The package supports reflow soldering per JEDEC J-STD-020 and is lead-free (RoHS-compliant).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6720AUTWGD3+T, the MAX6720AUTWD3+T requires external biasing and offers no push-pull advantage, while the TPS3808G33DBVR reduces feature set and monitoring flexibility to achieve lower supply current-making MAX6720AUTWGD3+T the optimal choice for designs needing guaranteed reset drive strength, triple-rail coverage, and robust software supervision.

Availability

MAX6720AUTWGD3+T is available at Aetrix Electronics and suitable for telecom infrastructure, industrial PLCs, portable medical devices, and set-top box power management requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MAX6720AUTWGD3+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) is a semiconductor company specializing in analog and mixed-signal ICs for power management, sensing, and interface applications.

The MAX6715–MAX6729 family was designed for multivoltage embedded systems requiring precise, low-power supervision of primary, secondary, and auxiliary rails-with emphasis on brownout resilience, watchdog reliability, and minimal PCB footprint.

FAQ

What is the exact reset threshold voltage for VCC1 on the MAX6720AUTWGD3+T?

The MAX6720AUTWGD3+T has a factory-trimmed VCC1 reset threshold of 4.625 V (typical, falling edge), as indicated by the "W" suffix in its part number per Maxim's Reset Voltage Threshold Suffix Guide. This value is guaranteed over -40°C to +85°C with ±1.5% tolerance and 20 ppm/°C tempco, ensuring consistent reset assertion during 5 V rail collapse in telecom and industrial applications.

Does the MAX6720AUTWGD3+T support monitoring a third voltage rail, and how is it configured?

Yes, the MAX6720AUTWGD3+T supports third-rail monitoring via its RSTIN pin, which compares the applied voltage against an internal 626.5 mV reference. To monitor a rail like 1.2 V, connect a resistor divider (e.g., R1 = 1.0 MΩ, R2 = 511 kΩ) between the rail and GND, feeding the junction to RSTIN. The MAX6720AUTWGD3+T guarantees RSTIN input current ≤±25 nA, enabling high-impedance, low-power monitoring without loading the source.

What is the function of the "D3" suffix in MAX6720AUTWGD3+T, and how does it affect timing?

The "D3" suffix in MAX6720AUTWGD3+T specifies a minimum reset timeout period of 210 ms, per Maxim's Reset Timeout Period Suffix Guide. This duration ensures the reset signal remains asserted long enough for complex processors (e.g., ARM Cortex-A series) to complete boot ROM execution and initialize critical peripherals before release-preventing race conditions that could cause unstable startup in embedded systems.

How does the watchdog timer in MAX6720AUTWGD3+T operate during system boot and runtime?

The MAX6720AUTWGD3+T implements a dual-mode watchdog: after power-up or manual reset, it enters a 35 s (min) startup mode to accommodate lengthy firmware initialization; upon detecting the first valid WDI edge, it switches to 1.12 s (min) normal mode. If the host processor fails to toggle WDI within this window, the MAX6720AUTWGD3+T asserts RST for 210 ms-providing fail-safe recovery without requiring software-modifiable timeout registers.

Is the MAX6720AUTWGD3+T compatible with systems where the main supply voltage drops below 1.0 V during brownout?

Yes, the MAX6720AUTWGD3+T guarantees correct reset output logic state even when VCC1 or VCC2 falls to 0.8 V, per its Absolute Maximum Ratings and Electrical Characteristics table. This ensures deterministic reset assertion during deep brownout events-critical for battery-backed systems where supply decay may extend below typical MCU operating voltage, preventing undefined processor behavior.