Analog Devices Inc./Maxim Integrated MAX6358SYUT

Overview

MAX6358SYUT from Maxim Integrated is a dual-voltage microprocessor supervisory IC with open-drain active-low reset output, 2.93V VCC1 threshold, 2.19V VCC2 threshold, 20µA supply current, and integrated watchdog timer featuring 46.4s startup timeout and 2.9s normal timeout. It monitors two independent power rails in embedded systems requiring reliable power-on reset and processor activity supervision.

For engineers reviewing the MAX6358SYUT datasheet, MAX6358SYUT pinout, MAX6358SYUT application, or MAX6358SYUT equivalent, this device is selected for dual-rail monitoring where VCC1 ≥ 2.93V and VCC2 ≥ 2.19V must be validated before release of reset, with watchdog supervision critical for firmware recovery in industrial controllers and portable instrumentation.

Technical Context

The MAX6358SYUT implements a dual-threshold voltage monitor with independent trip points on VCC1 (2.93V) and VCC2 (2.19V), asserting reset if either supply falls below its respective threshold. Its open-drain RST output remains valid down to VCC1 = 1V or VCC2 = 1V, enabling operation during brownout conditions.

It integrates a dual-mode watchdog timer: a 46.4s startup timeout allows full system initialization after power-up or manual reset, followed by a 2.9s normal timeout requiring periodic WDI edge transitions to prevent reset. The debounced MR input supports TTL/CMOS logic levels and guarantees reset assertion for ≥1µs pulses.

Key Specifications

Pinout & Package

MAX6358SYUT is housed in a 6-pin SOT23-6 package with 1.6mm × 2.9mm footprint, 0.95mm height, and 0.95mm pitch - compatible with standard high-density PCB assembly processes.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6358SYUT, MAX6359SYUT offers push-pull drive eliminating external pull-up but sacrifices bus-sharing flexibility, while TPS3808G33DBVR provides lower-cost single-rail supervision at the expense of missing dual-monitoring and watchdog functionality essential for autonomous recovery.

Availability

MAX6358SYUT is available at Aetrix Electronics and suitable for industrial PLC controllers, portable medical instruments, network edge gateways, and automotive body control modules requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6358SYUT 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, and computing applications, emphasizing high reliability and low power.

The MAX6351–MAX6360 family delivers dual- and triple-voltage supervision with integrated watchdog timers specifically for embedded systems needing guaranteed power sequencing and firmware liveness assurance.

FAQ

What is the exact reset threshold voltage for VCC1 and VCC2 on the MAX6358SYUT?

The MAX6358SYUT has a factory-trimmed VCC1 threshold of 2.93V (±0.05V) and a VCC2 threshold of 2.19V (±0.03V), corresponding to the "SY" suffix in the Voltage Threshold Levels table. These values are fully guaranteed over the -40°C to +85°C operating range and require no external calibration. The MAX6358SYUT uses these precise thresholds to supervise +3.0V and +2.2V rails independently.

Does the MAX6358SYUT provide an active-high or active-low reset output, and what is its drive type?

The MAX6358SYUT provides a single active-low reset output (RST) implemented as an open-drain driver. This means the output pulls low when asserted but requires an external pull-up resistor to establish a logic-high state. The MAX6358SYUT's open-drain architecture enables wired-OR connection with other reset sources on a shared reset bus, unlike push-pull variants such as MAX6359SYUT.

How does the watchdog timer on the MAX6358SYUT operate during power-up and normal operation?

The MAX6358SYUT watchdog operates in two phases: a 46.4s startup timeout begins after any reset event (power-up, MR assertion, or watchdog timeout), allowing full system initialization; then it transitions to a 2.9s normal timeout requiring periodic WDI edge transitions. If no WDI transition occurs within that window, the MAX6358SYUT asserts RST. This dual-mode behavior prevents false resets during boot while ensuring rapid fault detection afterward.

Can the MAX6358SYUT monitor three voltage rails, or is it limited to two?

The MAX6358SYUT is strictly a dual-voltage supervisor and does not support a third monitored rail. Only the MAX6355/MAX6356/MAX6357 variants include the RSTIN pin for adjustable third-rail monitoring (typically 1.22V threshold). The MAX6358SYUT lacks RSTIN and instead features the WDI pin for watchdog functionality-its pinout and internal architecture are optimized for two-rail supervision plus watchdog, not triple monitoring.

What is the minimum supply voltage required for the MAX6358SYUT to maintain valid reset output behavior?

The MAX6358SYUT guarantees valid RST output state as long as either VCC1 ≥ 1.0V or VCC2 ≥ 1.0V, per Absolute Maximum Ratings and Electrical Characteristics tables. This "1V validity" ensures reliable reset signaling during severe brownout conditions where one rail collapses below nominal but remains above 1V. The MAX6358SYUT continues asserting or deasserting RST correctly under this condition, supporting fail-safe system behavior.