Analog Devices Inc./Maxim Integrated MAX6355TWUT+T

Overview

MAX6355TWUT+T from Maxim Integrated is a triple-voltage microprocessor supervisory circuit with open-drain reset output, monitoring VCC1 (3.08V threshold), VCC2 (1.67V threshold), and a third voltage via RSTIN (1.22V fixed comparator input). It operates from -40°C to +85°C in a 6-pin SOT23 package and supports systems requiring reliable power-on reset, manual reset debouncing, and supply fault detection across three rails - e.g., FPGA-based embedded controllers with core, I/O, and auxiliary bias supplies.

For engineers reviewing the MAX6355TWUT+T datasheet, MAX6355TWUT+T pinout, MAX6355TWUT+T application, or MAX6355TWUT+T equivalent, key selection criteria include its dual-supply monitoring capability, guaranteed RESET validity down to VCC1 = 1V or VCC2 = 1V, 100ms minimum reset pulse width, 20µA quiescent current, and compatibility with multivoltage systems requiring third-rail supervision without external resistors.

Technical Context

The MAX6355TWUT+T implements independent precision voltage comparators for VCC1 and VCC2, each with factory-trimmed thresholds (3.08V ±0.08V and 1.67V ±0.05V over temperature), plus a dedicated 1.22V ±0.03V RSTIN comparator for monitoring a third rail. Its open-drain RST output is referenced to VCC1 and remains valid as long as either VCC1 ≥ 1.0V or VCC2 ≥ 1.0V.

It features a debounced TTL/CMOS-compatible manual-reset input (MR), power-supply transient immunity up to 250µs at 100mV overdrive, and guaranteed operation across -40°C to +85°C. Unlike MAX6358–MAX6360 variants, it lacks watchdog functionality but adds RSTIN for flexible third-voltage supervision.

Key Specifications

Pinout & Package

MAX6355TWUT+T is housed in a RoHS-compliant 6-pin SOT23 package (U6-1 outline, land pattern 90-0175), measuring 2.9mm × 1.6mm × 1.1mm, with gull-wing leads and thermal pad not connected internally.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6356TWUT+T, MAX6355TWUT+T offers open-drain flexibility for bus sharing and level translation, while versus TPS3808G33DBVR it delivers true integrated triple-rail supervision without external components - critical for minimizing footprint and validation effort in compact multivoltage designs.

Availability

MAX6355TWUT+T is available at Aetrix Electronics and suitable for FPGA power sequencing, industrial PLC controllers, battery-powered medical sensors, and multivoltage IoT edge nodes requiring stable component supply and long-term lifecycle support.

Supply support for MAX6355TWUT+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, computing, and communications applications, with emphasis on reliability, integration, and low-power operation.

The MAX6351–MAX6360 family targets multivoltage embedded systems needing precise, low-quiescent-current supervision - especially where space, BOM count, and brownout resilience are critical constraints.

FAQ

What is the exact reset threshold voltage for VCC1 on the MAX6355TWUT+T?

The MAX6355TWUT+T has a factory-trimmed VCC1 reset threshold of 3.08V, with guaranteed tolerance of ±0.08V over the full -40°C to +85°C operating temperature range. This value corresponds to the "T" suffix in the part number and is confirmed in the Voltage Threshold Levels table of the official datasheet. The MAX6355TWUT+T uses this threshold to assert reset when the primary supply falls below specification, ensuring reliable power-on sequencing for 3.3V-based systems.

Does the MAX6355TWUT+T include a watchdog timer function?

No, the MAX6355TWUT+T does not include a watchdog timer. Watchdog functionality is exclusive to the MAX6358, MAX6359, and MAX6360 variants in the same family. The MAX6355TWUT+T instead provides an RSTIN input for third-voltage supervision, distinguishing it from watchdog-equipped versions. This makes the MAX6355TWUT+T ideal for applications requiring triple-rail monitoring without timer-based processor activity checks.

What is the function of Pin 5 (RSTIN) on the MAX6355TWUT+T?

Pin 5 (RSTIN) on the MAX6355TWUT+T is a dedicated undervoltage-reset comparator input with a fixed 1.22V threshold. It allows supervision of a third voltage rail - for example, a 1.2V or 1.8V domain - using an external resistor divider to scale the target voltage down to the 1.22V reference. The MAX6355TWUT+T asserts reset if the voltage at RSTIN falls below this threshold, enabling true triple-supply monitoring without additional ICs or passive components beyond the divider.

Can the MAX6355TWUT+T operate with VCC1 and VCC2 below 1.8V?

Yes, the MAX6355TWUT+T guarantees functional reset output as long as either VCC1 ≥ 1.0V or VCC2 ≥ 1.0V, and its electrical specifications are validated down to VCC1 = VCC2 = 1.2V. The VCC2 threshold is 1.67V, making it suitable for monitoring 1.8V rails with margin; operation at 1.2V on VCC2 is outside its specified monitoring range but within its minimum supply requirement for RST validity. The MAX6355TWUT+T thus supports brownout detection in low-voltage systems while maintaining reset integrity.

Is the MAX6355TWUT+T pin-compatible with other devices in the MAX6351–MAX6360 family?

The MAX6355TWUT+T shares the same 6-pin SOT23 (U6-1) package and pinout as MAX6351, MAX6356, MAX6357, MAX6358, MAX6359, and MAX6360 - including identical assignments for GND (Pin 2), MR (Pin 3), VCC2 (Pin 4), RSTIN/WDI (Pin 5), and VCC1 (Pin 6). However, Pin 1 differs: MAX6355TWUT+T uses it as open-drain RST, whereas MAX6351 uses it as RST1 and MAX6356/MAX6357 use it as push-pull RST. Therefore, board-level substitution requires verification of reset output type and load compatibility.