Analog Devices Inc./Maxim Integrated MAX6727KASDD3+

Overview

MAX6727KASDD3+ 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 RSTIN input (626.5mV reference). It provides two open-drain active-low reset outputs (RST and RST2), manual reset input (MR), watchdog timer (35s startup / 1.12s normal timeout), and operates from -40°C to +85°C. It ensures reliable system boot and brownout recovery in multivoltage embedded power rails.

For engineers reviewing the MAX6727KASDD3+ datasheet, MAX6727KASDD3+ pinout, MAX6727KASDD3+ application, or MAX6727KASDD3+ equivalent, key selection criteria include dual independent reset outputs, factory-trimmed dual-supply thresholds with third-voltage adjustability via resistor divider, guaranteed reset validity down to VCC1/VCC2 = 0.8V, and integrated watchdog with long startup period for complex firmware initialization.

Technical Context

The MAX6727KASDD3+ implements a dual-comparator architecture with independent voltage sensing paths for VCC1 and VCC2, plus a high-impedance RSTIN comparator referenced to a 626.5mV internal bandgap. Reset assertion is latched by a programmable timeout timer (210ms min) that restarts on any threshold violation before expiry.

Its dual open-drain RST outputs are electrically isolated: RST is referenced to VCC1 and asserts on VCC1, VCC2, RSTIN, or MR faults; RST2 is referenced to VCC2 and asserts only on VCC1, VCC2, or MR faults - enabling independent reset control of core and I/O domains. The watchdog features dual-mode timing: 35s minimum after power-up or reset, then 1.12s minimum during normal operation upon WDI edge detection.

Key Specifications

Pinout & Package

MAX6727KASDD3+ uses an 8-pin SOT23-8 package with exposed pad (thermal enhancement), pin-compatible with industry-standard 8-lead SOT23 footprints. Pin 1 is marked with dot; pin numbering follows standard SOT23-8 convention (counterclockwise from mark).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6727KASDD5+, the MAX6727KASDD3+ offers half the reset timeout for faster system responsiveness; compared with TPS3808G33DBVR, it provides triple-supply monitoring, dual independent reset outputs, and adjustable third-rail supervision - making it uniquely suited for complex multivoltage embedded systems requiring granular reset control.

Availability

MAX6727KASDD3+ is available at Aetrix Electronics and suitable for industrial PLC controllers, network router power management, medical diagnostic imaging modules, automotive ADAS camera ECUs, and telecom base station power sequencing requiring stable component supply across extended temperature ranges.

Supply support for MAX6727KASDD3+ 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, mixed-signal, and power management ICs for industrial, computing, communications, and automotive markets.

The MAX6715–MAX6729 family delivers ultra-low-voltage, multirail supervisory circuits optimized for space-constrained embedded systems requiring guaranteed reset validity down to 0.8V and flexible configuration of dual/three supply monitoring.

FAQ

What is the exact reset timeout period for MAX6727KASDD3+?

The MAX6727KASDD3+ has a minimum reset timeout period of 210ms, as indicated by the 'D3' suffix in its part number. This is the guaranteed minimum duration for which the RST and RST2 outputs remain asserted after all monitored voltages exceed their thresholds or after MR release. Typical value is 210ms, maximum is 280ms over temperature and voltage range.

Does MAX6727KASDD3+ support monitoring a 1.2V rail as the third voltage?

Yes, MAX6727KASDD3+ supports monitoring a 1.2V rail via its RSTIN pin using a resistor divider. With the internal 626.5mV reference, a 1.2V rail can be scaled using R1 = 910kΩ and R2 = 1MΩ (VEXT_TH = 626.5mV × (R1+R2)/R2 ≈ 1.2V). Input leakage is only ±25nA, enabling high-resistor values to minimize current draw.

How are the two reset outputs (RST and RST2) functionally different in MAX6727KASDD3+?

In MAX6727KASDD3+, RST asserts on VCC1, VCC2, RSTIN, MR, or watchdog faults and is referenced to VCC1; RST2 asserts only on VCC1, VCC2, or MR faults and is referenced to VCC2. This allows independent reset control - for example, holding a 3.3V FPGA in reset (RST2) while releasing a 5V microcontroller (RST) after its rail stabilizes.

Can MAX6727KASDD3+ operate with VCC1 = 2.5V and VCC2 = 1.8V?

Yes, MAX6727KASDD3+ fully supports VCC1 = 2.5V and VCC2 = 1.8V. Its VCC1 monitor range is 1.8V–5.0V and VCC2 range is 0.9V–3.3V. The device guarantees correct reset logic state as long as either supply remains ≥0.8V, and supply current remains ultra-low (ICC1 ≈ 4µA at 2.5V, ICC2 ≈ 3µA at 1.8V).

Is there a push-pull version of MAX6727KASDD3+?

No - MAX6727KASDD3+ is specifically configured with two open-drain reset outputs (RST and RST2). The MAX6726KA_ _D_ -T variant offers push-pull RST and RST2, but MAX6727 is designated for open-drain-only operation per the Selector Guide. The 'K' prefix and 'SDD' suffix confirm dual open-drain outputs and SOT23-8 package.