Analog Devices Inc./Maxim Integrated MAX6358LSUT-T

Overview

MAX6358LSUT-T from Maxim Integrated is a dual-voltage microprocessor supervisory circuit with active-low open-drain reset output, 4.63V VCC1 threshold, 2.93V VCC2 threshold, 46.4s watchdog startup timeout, and 2.9s normal watchdog timeout-designed for reliable power monitoring in multivoltage embedded systems such as industrial controllers and portable instrumentation.

For engineers reviewing the MAX6358LSUT-T datasheet, MAX6358LSUT-T pinout, MAX6358LSUT-T application, or MAX6358LSUT-T equivalent, key selection criteria include its dual-supply reset assertion logic, guaranteed RESET validity down to VCC1 = 1V or VCC2 = 1V, 20µA supply current, and SOT23-6 package compatibility with space-constrained PCB layouts.

Technical Context

The MAX6358LSUT-T implements independent voltage monitoring on VCC1 and VCC2 inputs, asserting reset if either supply drops below its factory-set threshold (4.63V and 2.93V respectively). Its open-drain RST output requires an external pullup and remains valid as long as at least one supply exceeds +1.0V.

It integrates a dual-mode watchdog timer: a 46.4s startup timeout enables full system initialization after power-up or manual reset, followed by a 2.9s normal timeout that triggers reset upon missing WDI transitions. The debounced MR input supports TTL/CMOS-compatible manual reset initiation.

Key Specifications

Pinout & Package

MAX6358LSUT-T is housed in a 6-pin SOT23 package (U6-1 outline), surface-mount compatible with standard reflow profiles and footprint 90-0175 per Maxim's land pattern documentation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6358LSUT-T, MAX6359LSUT-T offers push-pull drive for direct µP interface but forfeits open-drain flexibility, while TPS3808G33DBVR trades dual-voltage capability and watchdog for lower quiescent current and tighter threshold tolerance-making each suitable only for distinct system architecture constraints.

Availability

MAX6358LSUT-T is available at Aetrix Electronics and suitable for industrial controllers, portable instrumentation, intelligent power supplies, and multivoltage embedded systems requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MAX6358LSUT-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 high-performance analog and mixed-signal ICs for industrial, automotive, and communications applications, emphasizing precision, integration, and reliability.

The MAX6351–MAX6360 family delivers dual- and triple-voltage µP supervision with integrated watchdog timers, targeting systems where simultaneous monitoring of multiple rails and fail-safe boot integrity are critical design requirements.

FAQ

What is the function of the WDI pin on the MAX6358LSUT-T?

The WDI (Watchdog Input) pin on the MAX6358LSUT-T monitors microprocessor activity: a rising or falling edge resets the internal watchdog timer. If no transition occurs within 2.9s during normal operation-or within 46.4s during initial startup-the MAX6358LSUT-T asserts its RST output. This prevents system lockup by forcing a controlled restart when firmware stalls.

Does the MAX6358LSUT-T support operation with VCC1 or VCC2 below 1.2V?

Yes-the MAX6358LSUT-T guarantees valid RST output as long as either VCC1 ≥ 1.0V or VCC2 ≥ 1.0V, per Absolute Maximum Ratings and Electrical Characteristics. However, full specification (e.g., threshold accuracy, watchdog timing) applies only over the -40°C to +85°C range with VCC1/VCC2 ≥ 1.2V, as noted in the datasheet's operating conditions.

How does the MAX6358LSUT-T handle simultaneous undervoltage on both VCC1 and VCC2?

When both VCC1 falls below 4.63V and VCC2 falls below 2.93V, the MAX6358LSUT-T immediately asserts its active-low RST output. The reset remains asserted until both supplies recover above their respective thresholds and the internal reset timeout (100ms minimum) completes-ensuring clean, synchronized recovery across all monitored rails.

Can the MAX6358LSUT-T be used in a system with only one supply voltage?

Yes-the MAX6358LSUT-T can monitor a single supply by connecting the unused rail (e.g., VCC2) to the same source as VCC1 or to a stable voltage within its 1.2V–5.5V operating range. Its dual-threshold architecture still functions, though full benefit requires two independent rails. MR and WDI remain fully operational for manual reset and watchdog oversight.

What is the maximum allowable voltage on the MR pin of the MAX6358LSUT-T?

The MR pin voltage must not exceed VCC1, as explicitly stated in the Pin Description section. For the MAX6358LSUT-T, MR is TTL/CMOS-compatible with VIH ≥ 2.3V (when VCC1 > VTH1_MAX) and VIL ≤ 0.8V. Driving MR above VCC1 risks latch-up or damage; it must be referenced to and bounded by the VCC1 supply.