Analog Devices Inc./Maxim Integrated MAX6720UTSVD3+T

Overview

MAX6720UTSVD3+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 (626.5mV reference). It asserts active-low push-pull reset for ≥210ms after any monitored supply drops below threshold or manual reset is triggered, and supports watchdog timeout with 35s startup and 1.12s normal mode. It is used in multivoltage embedded systems requiring reliable power-up sequencing and brownout protection.

For engineers reviewing the MAX6720UTSVD3+T datasheet, MAX6720UTSVD3+T pinout, MAX6720UTSVD3+T application, or MAX6720UTSVD3+T equivalent, key selection criteria include dual-supply monitoring with factory-trimmed thresholds, push-pull RST output referenced to VCC1, 210ms minimum reset timeout, guaranteed reset validity down to VCC1/VCC2 = 0.8V, and integrated watchdog with long/short dual-mode timing.

Technical Context

The MAX6720UTSVD3+T implements a dual-threshold voltage monitor (VCC1 at 4.625V ±125mV, VCC2 at 3.075V ±75mV) plus an auxiliary comparator on RSTIN with 626.5mV internal reference, enabling third-voltage supervision via external resistor divider. Its reset logic combines OR-ed fault detection across all three inputs and maintains asserted state for a fixed 210ms timeout after recovery.

This device uses BiCMOS process (1072 transistors), features 14µA typical supply current at 3.6V, and guarantees correct reset output logic when either VCC1 or VCC2 remains above 0.8V - critical for low-voltage system operation. The push-pull RST output is referenced to VCC1 and sinks up to 3.2mA at 4.5V.

Key Specifications

Pinout & Package

MAX6720UTSVD3+T is housed in a 6-pin SOT23-6 package (2.9mm × 1.6mm × 1.1mm), surface-mount, lead-free (+T suffix), rated for -40°C to +85°C operation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6720UTSVD3+T, the MAX6720UTSVD2+T offers identical functionality with reduced reset timeout, while TPS3808G33DBVR lacks triple monitoring, adjustable input, and integrated watchdog - making it unsuitable for complex multivoltage systems requiring coordinated reset and runtime supervision.

Availability

MAX6720UTSVD3+T is available at Aetrix Electronics and suitable for industrial PLCs, telecom line cards, embedded medical sensor hubs, and set-top box power management requiring stable component supply, guaranteed long-term availability, and full traceability.

Supply support for MAX6720UTSVD3+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 high-performance analog, mixed-signal, and power management ICs for industrial, communications, and computing markets.

The MAX6715–MAX6729 family was designed specifically for ultra-low-voltage, space-constrained multivoltage systems requiring precise, factory-trimmed power supervision with minimal external components and extended temperature operation.

FAQ

What is the exact reset timeout period of the MAX6720UTSVD3+T?

The MAX6720UTSVD3+T 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 after power recovery or manual reset assertion. The actual timeout may vary slightly due to process and temperature but remains within specification limits.

Does the MAX6720UTSVD3+T support monitoring a third voltage, and how is it configured?

Yes, the MAX6720UTSVD3+T supports third-voltage monitoring via its RSTIN pin, which features a precise 626.5mV internal reference. To configure it, connect an external resistor divider between the target supply and ground, with the midpoint fed into RSTIN. The monitored threshold is calculated as V_{EXT_TH} = 626.5mV × ((R1 + R2)/R2). This allows flexible supervision of auxiliary rails such as battery backups or isolated supplies without trimming or calibration.

Is the reset output of the MAX6720UTSVD3+T push-pull or open-drain?

The MAX6720UTSVD3+T features an active-low push-pull RST output, as confirmed by its "T" suffix in the Selector Guide and functional description. This means the output actively drives low during reset and high when deasserted - eliminating the need for an external pullup resistor. The high-level output is referenced to VCC1 and meets VOH ≥ 0.8 × VCC1 under specified load conditions.

Can the MAX6720UTSVD3+T operate reliably when VCC1 drops below 1.0V?

Yes, the MAX6720UTSVD3+T guarantees valid reset output logic down to VCC1 or VCC2 = 0.8V, per Absolute Maximum Ratings and Electrical Characteristics tables. This ensures correct reset assertion during deep brownout conditions. However, for operation down to 0V, a 100kΩ pull-down resistor from RST to GND is recommended - though this applies only to push-pull variants like the MAX6720UTSVD3+T when used in systems requiring guaranteed low-state behavior at zero supply.

What watchdog timeout modes does the MAX6720UTSVD3+T support?

The MAX6720UTSVD3+T implements a dual-mode watchdog timer: a 35s minimum startup timeout after any reset event (power-up, MR, or watchdog-triggered), followed by a 1.12s minimum normal-mode timeout after the first valid WDI transition. This architecture prevents false timeouts during lengthy boot sequences while ensuring rapid detection of software hangs during steady-state operation - a key requirement for safety-critical embedded firmware.