Analog Devices Inc./Maxim Integrated MAX6720UTSDD3

Overview

MAX6720UTSDD3 from Maxim Integrated is a triple-voltage microprocessor supervisory circuit in 6-pin SOT23 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 guarantees valid reset output down to VCC1 or VCC2 = 0.8V. Used in multivoltage telecom power systems requiring reliable brownout detection and orderly shutdown.

For engineers reviewing the MAX6720UTSDD3 datasheet, MAX6720UTSDD3 pinout, MAX6720UTSDD3 application, or MAX6720UTSDD3 equivalent, this page delivers verified electrical parameters, exact pin functions, confirmed dual-supply + auxiliary voltage monitoring capability, push-pull reset output behavior, and real-world design implications of its 210ms min timeout and 14µA typical supply current.

Technical Context

The MAX6720UTSDD3 implements a dual-threshold comparator architecture with factory-trimmed VCC1 and VCC2 reset thresholds (4.625V and 3.075V), plus a high-impedance RSTIN input referenced to a 626.5mV internal bandgap. Its push-pull RST output is driven from VCC1 and remains asserted for a guaranteed minimum 210ms after all monitored voltages recover.

It integrates a dual-mode watchdog timer: 35s minimum startup period after reset, followed by 1.12s minimum normal timeout upon first WDI transition. Manual reset (MR) features internal 50kΩ pullup to VCC1 and 200ns MR-to-reset delay, enabling direct switch interfacing without external components.

Key Specifications

Pinout & Package

MAX6720UTSDD3 is housed in a 6-pin SOT23-6 package (2.9mm × 1.6mm × 1.1mm), optimized for space-constrained multivoltage PCBs. Pin functions are validated per Maxim's official pin description table for MAX6719/MAX6720 variants.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6720UTSDD3, MAX6720UTSD3-T offers identical supervision functionality in the same package with no design changes required, while TPS3808G33DBVR necessitates redesign to add external voltage dividers and second supervisor IC - increasing layout complexity and reducing reliability.

Availability

MAX6720UTSDD3 is available at Aetrix Electronics and suitable for telecom power sequencing, industrial PLC I/O modules, battery-powered test equipment, and network switch line cards requiring stable component supply with guaranteed long-term availability.

Supply support for MAX6720UTSDD3 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 management, sensing, and interface applications, serving industrial, automotive, and communications markets.

The MAX6715–MAX6729 family was engineered specifically for multivoltage embedded systems needing compact, ultra-low-power supervision of primary, secondary, and auxiliary rails - with emphasis on guaranteed reset validity at sub-1V supply levels.

FAQ

What is the exact reset timeout period for MAX6720UTSDD3?

The MAX6720UTSDD3 has a minimum reset timeout period of 210ms, as indicated by the 'D3' suffix in its part number. This value is guaranteed over the full -40°C to +85°C operating temperature range and ensures sufficient hold time for microprocessor initialization sequences. The actual timeout may vary slightly with temperature and supply voltage but will never fall below 210ms under specified conditions.

Does MAX6720UTSDD3 support monitoring a third voltage, and how is it configured?

Yes, MAX6720UTSDD3 supports third-voltage monitoring via its RSTIN pin, which compares the applied voltage against an internal 626.5mV reference. To monitor a target voltage (e.g., 1.2V), connect a resistor divider between that supply and ground, with the midpoint fed to RSTIN. The formula is V_{EXT_TH} = 626.5mV × (R1 + R2)/R2. MAX6720UTSDD3's ±25nA RSTIN input current enables use of high-value resistors to minimize power draw.

What are the voltage ranges supported for VCC1 and VCC2 on MAX6720UTSDD3?

MAX6720UTSDD3 supports VCC1 from 1.8V to 5.0V (with factory-trimmed 4.625V reset threshold) and VCC2 from 0.9V to 3.3V (with factory-trimmed 3.075V reset threshold). Critically, the device guarantees correct reset output logic state even when either VCC1 or VCC2 drops as low as 0.8V - enabling robust operation during deep brownout events.

Is the reset output of MAX6720UTSDD3 push-pull or open-drain, and what are its drive capabilities?

MAX6720UTSDD3 features a push-pull active-low RST output referenced to VCC1. It can sink up to 3.2mA at VCC1 ≥ 4.5V (V_OL ≤ 0.4V) and source 800µA while maintaining V_OH ≥ 0.8 × VCC1. This eliminates the need for an external pullup resistor and provides stronger noise immunity than open-drain alternatives - critical for reliable µP reset signaling.

How does the watchdog timer in MAX6720UTSDD3 operate during system startup?

MAX6720UTSDD3 implements a dual-mode watchdog: after any reset event (power-up, brownout, or manual reset), it enters a 35s minimum startup mode to allow full system initialization. Upon detecting the first valid edge on WDI, it switches to 1.12s minimum normal timeout mode. This prevents false resets during boot while ensuring rapid fault detection once the system is operational - a key advantage over fixed-timer supervisors.