Analog Devices Inc./Maxim Integrated MAX6727KAYDD3+T

Overview

MAX6727KAYDD3+T from Maxim Integrated is a triple-voltage microprocessor supervisory circuit in an 8-pin SOT23 package, monitoring VCC1 (4.625V threshold), VCC2 (3.075V threshold), and an externally adjustable third supply via RSTIN (626.5mV reference). It provides dual open-drain active-low reset outputs (RST and RST2), manual reset input, watchdog timer with 35s startup/1.12s normal timeout, and operates from -40°C to +85°C. It ensures reliable power-up sequencing and brownout protection in multivoltage embedded systems.

For engineers reviewing the MAX6727KAYDD3+T datasheet, MAX6727KAYDD3+T pinout, MAX6727KAYDD3+T application, or MAX6727KAYDD3+T equivalent, key selection criteria include dual independent reset outputs, factory-trimmed dual-threshold supervision (4.625V/3.075V), RSTIN-based auxiliary voltage monitoring down to 0.62V, 210ms minimum reset timeout, and guaranteed reset validity with VCC1 or VCC2 ≥ 0.8V.

Technical Context

The MAX6727KAYDD3+T implements a dual-threshold comparator architecture for primary (VCC1) and secondary (VCC2) supplies, plus a dedicated high-impedance RSTIN input referenced to a 626.5mV internal bandgap. Its dual open-drain RST outputs are independently driven by the same internal logic but routed to separate pins (Pin 1 and Pin 4), enabling distinct system reset domains.

It integrates a dual-mode watchdog timer: a 35s minimum initial timeout after any reset event (power-up, MR, or watchdog expiry), followed by a 1.12s minimum normal timeout triggered by the first WDI edge. The manual reset input (MR) features a 50kΩ internal pullup to VCC1 and 200ns propagation delay to reset assertion.

Key Specifications

Pinout & Package

MAX6727KAYDD3+T is housed in an 8-pin SOT23-8 package (2.0mm × 2.1mm, 0.65mm pitch), optimized for space-constrained PCB layouts in portable and networking equipment.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6727KAYDD3+T, MAX6725KAUTD3+T offers push-pull RST2 but omits RSTIN and second open-drain RST, while TPS3808G33DBVR reduces feature set to basic dual-rail monitoring with lower power-making MAX6727KAYDD3+T uniquely suited for triple-supply systems requiring dual independent reset outputs and flexible auxiliary rail supervision.

Availability

MAX6727KAYDD3+T is available at Aetrix Electronics and suitable for industrial PLC controllers, 5G small cell baseband units, medical patient monitors, and enterprise SSD controller boards requiring stable component supply, precise multivoltage supervision, and dual-domain reset control.

Supply support for MAX6727KAYDD3+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) designs precision analog and mixed-signal ICs for industrial, communications, computing, and consumer applications, emphasizing reliability, integration, and low-power operation.

The MAX6715–MAX6729 family delivers ultra-low-voltage, multirail microprocessor supervision in miniature SOT23 packages, targeting space-constrained systems requiring robust power-monitoring, watchdog safety, and flexible reset architectures.

FAQ

What is the exact reset threshold voltage for VCC1 on the MAX6727KAYDD3+T?

The MAX6727KAYDD3+T has a factory-trimmed VCC1 reset threshold of 4.625V, with a typical tolerance of ±125mV (4.500V to 4.750V). This value is encoded in the "Y" suffix per Maxim's Reset Voltage Threshold Suffix Guide and is verified across temperature (-40°C to +85°C) and supply conditions. The MAX6727KAYDD3+T uses this precise threshold to supervise 5V or 4.8V system rails without external calibration.

Does the MAX6727KAYDD3+T provide two independent reset outputs, and how are they configured?

Yes, the MAX6727KAYDD3+T provides two independent active-low open-drain reset outputs: RST (Pin 1) and RST2 (Pin 4). Both are driven by the same internal reset logic and assert simultaneously under identical conditions (VCC1/VCC2/RSTIN undervoltage, MR low, or watchdog timeout), but are physically isolated for routing to separate subsystems. The MAX6727KAYDD3+T does not support independent control or different timeout periods for each output.

How is the third supply voltage monitored using the RSTIN pin on the MAX6727KAYDD3+T?

The RSTIN pin on the MAX6727KAYDD3+T connects to an internal 626.5mV reference comparator. To monitor a third supply (e.g., 1.2V), a resistor divider (R1/R2) scales the supply so that the voltage at RSTIN equals 626.5mV at the desired trip point: V_{EXT_TH} = 626.5mV × (R1 + R2)/R2. The MAX6727KAYDD3+T asserts reset when RSTIN falls below 626.5mV, enabling precise undervoltage detection for auxiliary rails.

What is the watchdog timeout behavior of the MAX6727KAYDD3+T, and how does it differ between startup and normal operation?

The MAX6727KAYDD3+T features a dual-mode watchdog: after any reset event (power-up, MR, or timeout), it enters a 35s minimum startup mode to accommodate lengthy system initialization. Upon detecting the first valid WDI edge, it switches to a 1.12s minimum normal timeout mode. If WDI remains static beyond either period, the MAX6727KAYDD3+T asserts reset for 210ms. This architecture prevents false resets during boot while ensuring rapid fault response during runtime.

What package type and pin count does the MAX6727KAYDD3+T use, and what are its key mechanical dimensions?

The MAX6727KAYDD3+T uses an 8-pin SOT23-8 package (also labeled SOT-23-8 or SOT23-8), measuring 2.0mm × 2.1mm with 0.65mm lead pitch. It is a surface-mount, lead-free (RoHS-compliant) package with gull-wing leads, designed for high-density PCB layouts in portable and telecom equipment. The "+T" suffix confirms lead-free termination, and the device is rated for reflow soldering per JEDEC J-STD-020.