Analog Devices Inc./Maxim Integrated MAX6704SKA

Overview

The MAX6704SKA from Maxim Integrated is a low-voltage microprocessor supervisory circuit in an 8-pin SOT23 package, providing dual complementary reset outputs (active-low and active-high push-pull), an adjustable power-fail comparator (PFI/PFO), manual reset input (MR), and a reset-based watchdog timer with 1.6s timeout. It monitors a single supply voltage (e.g., +3.3V or +5.0V), guarantees valid reset down to VCC = 1V, and supports critical µP power monitoring in space-constrained embedded systems.

For engineers reviewing the MAX6704SKA datasheet, MAX6704SKA pinout, MAX6704SKA application, or MAX6704SKA equivalent, this device delivers precise voltage supervision, brownout protection, power-fail warning, and watchdog-triggered reset pulses - all within a compact footprint suitable for industrial controllers, automotive ECUs, and intelligent instrumentation where reliability and layout efficiency are essential.

Technical Context

The MAX6704SKA integrates a primary VCC reset generator with 140ms timeout, a dedicated reset-based watchdog (not independent WDO) that asserts RESET on timeout, and a fully independent power-fail comparator with 0.62V internal reference and external PFI input. Its dual push-pull RESET/RESET outputs provide simultaneous active-low and active-high signaling without external inverters.

Unlike MAX6701–MAX6707 variants, the MAX6704SKA lacks a separate WDO pin and instead routes watchdog overflow directly to the reset generator - resulting in a guaranteed reset pulse of fixed duration (140–300ms) upon watchdog timeout. The MR input features a 50kΩ internal pullup and 200ns delay, and the PFI input supports threshold setting via external resistor dividers for secondary supply monitoring.

Key Specifications

Pinout & Package

Package: 8-pin SOT23-8, 3.00mm × 1.75mm × 1.30mm body, lead-free compatible (KA-T suffix), -40°C to +125°C operating range.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6705SKA and MAX6708SKA, the MAX6704SKA uniquely combines dual-polarity reset outputs with integrated watchdog-triggered reset pulses - enabling compact, robust supervision in µP systems requiring both power integrity assurance and software hang recovery without additional logic or pins.

Availability

MAX6704SKA is available at Aetrix Electronics and suitable for industrial controllers, automotive ECUs, and medical instrumentation requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6704SKA 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, automotive, communications, and computing markets.

The MAX670x family was designed specifically for reliable, low-power microprocessor supervision in harsh environments - delivering precision voltage monitoring, watchdog safety, and power-fail warning in ultra-small packages.

FAQ

What is the reset threshold voltage for MAX6704SKA?

The MAX6704SKA has an S-suffix reset threshold of 4.38V, with ±2.5% tolerance over -40°C to +125°C. This value is factory-trimmed and specified in the Electrical Characteristics table. The 'S' denotes the 4.38V option per the Threshold Suffix Guide; other versions (e.g., T = 3.08V, R = 2.63V) exist but MAX6704SKA specifically uses the 4.38V threshold for compatibility with +3.3V or +5V systems requiring margin.

Does MAX6704SKA have a dedicated watchdog output (WDO) pin?

No, MAX6704SKA does not include a WDO pin. Unlike MAX6701–MAX6707 variants, it implements a reset-based watchdog: when the 1.6s watchdog timer expires due to missing WDI edges, it directly asserts the RESET and RESET outputs for the full reset timeout period (140–300ms). This eliminates the need for a separate watchdog alert signal while maintaining system recovery capability.

How is the power-fail warning configured on MAX6704SKA?

The MAX6704SKA uses the PFI pin as a high-impedance input referenced to an internal 0.62V comparator threshold. To configure power-fail detection for a secondary supply (e.g., 3.3V), connect PFI to a resistive divider from that supply to GND. The divider ratio is calculated so PFI reaches 0.62V just before the monitored rail drops out. When triggered, PFO goes low - usable as an interrupt or connected to MR for automatic reset initiation.

What are the key differences between MAX6704SKA and MAX6708SKA?

MAX6704SKA and MAX6708SKA share dual complementary reset outputs and PFI/PFO functionality, but MAX6704SKA includes a reset-based watchdog timer with WDI input, while MAX6708SKA omits the watchdog entirely (no WDI pin). Both use the same S-suffix 4.38V threshold and SOT23-8 package. MAX6704SKA adds runtime software supervision; MAX6708SKA offers lowest complexity and quiescent current for pure power-monitoring use cases.

Can MAX6704SKA monitor multiple supply voltages simultaneously?

No, MAX6704SKA monitors only one primary supply voltage (VCC) for reset generation. It does not support dual or triple adjustable reset inputs like MAX6701–MAX6703 variants. However, its PFI input enables indirect monitoring of a second supply via external resistor divider - providing early warning (PFO) or cascaded reset (PFO → MR), but not independent reset assertion based on that secondary rail.