Analog Devices Inc./Maxim Integrated MAX6719UTLTD1+

Overview

MAX6719UTLTD1+ from Maxim Integrated is a triple-voltage microprocessor supervisory circuit in 6-pin SOT23 package, monitoring VCC1 (1.575V threshold), VCC2 (3.075V threshold), and an externally adjustable RSTIN input (626.5mV reference). It asserts active-low open-drain reset for ≥1.1ms after any monitored supply drops below threshold or manual reset is triggered, and supports watchdog timer startup (35s) and normal mode (1.12s). Used in multivoltage telecom and portable equipment to ensure reliable power-up sequencing and brownout recovery.

For engineers reviewing the MAX6719UTLTD1+ datasheet, MAX6719UTLTD1+ pinout, MAX6719UTLTD1+ application, or MAX6719UTLTD1+ equivalent, key selection criteria include dual-supply monitoring with factory-trimmed thresholds, RSTIN-based third-voltage supervision down to 0.62V, guaranteed reset validity at VCC1/VCC2 ≥ 0.8V, low 14µA typical supply current, and immunity to short VCC transients.

Technical Context

The MAX6719UTLTD1+ integrates three independent voltage monitors: primary (VCC1), secondary (VCC2), and auxiliary (RSTIN), each with dedicated comparators and hysteresis (0.5% of VTH). Its reset logic combines ORed fault conditions - VCC1/VCC2 undervoltage, RSTIN undervoltage, or MR assertion - driving a single open-drain RST output with programmable timeout (1.1ms min).

It features a dual-mode watchdog timer: long initial period (35s min) for system boot, followed by short normal period (1.12s min) for runtime supervision, cleared on WDI edge transitions. The RSTIN input accepts external resistor-divider networks for precise third-voltage threshold setting, with 25nA max input current enabling high-impedance sensing.

Key Specifications

Pinout & Package

Package: 6-pin SOT23, surface-mount, 1.6mm × 2.9mm footprint, -40°C to +85°C operation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6720UTLTD1+, the MAX6719UTLTD1+ offers open-drain flexibility for mixed-voltage reset buses, while TPS3808G12DBVR trades RSTIN capability for ultra-low quiescent current-making MAX6719UTLTD1+ optimal for triple-rail integrity where deterministic reset signaling is critical.

Availability

MAX6719UTLTD1+ is available at Aetrix Electronics and suitable for telecom infrastructure, portable medical devices, and industrial sensor nodes requiring stable component supply, guaranteed reset behavior under brownout, and triple-voltage monitoring capability.

Supply support for MAX6719UTLTD1+ 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 across industrial, automotive, and communications markets.

The MAX6715–MAX6729 family delivers ultra-low-voltage supervisory circuits optimized for multirail embedded systems, emphasizing guaranteed reset validity at sub-1V supply levels and flexible third-voltage monitoring via RSTIN.

FAQ

What is the exact reset threshold voltage for VCC1 on the MAX6719UTLTD1+?

The MAX6719UTLTD1+ has a factory-trimmed VCC1 reset threshold of 1.575V (typical, falling), with ±1.5% tolerance over temperature. This value is encoded in the "LT" suffix per Maxim's Reset Voltage Threshold Suffix Guide and is validated across the full -40°C to +85°C operating range. The MAX6719UTLTD1+ uses this precise threshold to assert reset during 1.8V rail collapse, ensuring µP remains held until stable.

Does the MAX6719UTLTD1+ support watchdog functionality?

No, the MAX6719UTLTD1+ does not include watchdog timer capability. Per Maxim's Selector Guide, MAX6719 variants lack WDI pin and internal watchdog circuitry. Watchdog support begins with MAX6721 and higher part numbers. The MAX6719UTLTD1+ provides only voltage monitoring (VCC1, VCC2, RSTIN), manual reset (MR), and reset timeout - making it ideal for simpler, cost-optimized supervision where software activity monitoring is handled externally.

What is the function of the RSTIN pin on the MAX6719UTLTD1+?

The RSTIN pin on the MAX6719UTLTD1+ is a high-impedance input referenced to an internal 626.5mV bandgap voltage, enabling external adjustment of a third reset threshold via resistor divider. When the voltage at RSTIN falls below 626.5mV, the device asserts RST. This allows monitoring of auxiliary supplies (e.g., battery, analog rail) down to 0.62V. The MAX6719UTLTD1+ guarantees ≤25nA input current, permitting use of megaohm-level resistors to minimize system power draw.

Is the MAX6719UTLTD1+ pin-compatible with other parts in the MAX6715–MAX6729 family?

Yes, the MAX6719UTLTD1+ shares the same 6-pin SOT23 package and pinout with MAX6715, MAX6716, MAX6719, MAX6720, MAX6721, and MAX6722. Pin 1 (RST), Pin 2 (GND), Pin 3 (MR), Pin 4 (VCC2), Pin 5 (VCC1), and Pin 6 (RSTIN) are identical across these variants. However, functional differences exist - e.g., MAX6715 lacks RSTIN, MAX6720 uses push-pull RST - so electrical compatibility must be verified per application requirements before substitution.

What is the minimum supply voltage required for valid reset operation of the MAX6719UTLTD1+?

The MAX6719UTLTD1+ guarantees correct reset output logic state as long as either VCC1 or VCC2 remains ≥0.8V. Below this level, reset behavior is not specified. This 0.8V guarantee enables reliable operation during deep brownout conditions where one rail may collapse while the other sustains minimal bias. The MAX6719UTLTD1+ achieves this via internal biasing schemes that maintain comparator and timer functionality even at near-threshold supply levels.