Analog Devices Inc./Maxim Integrated MAX6346UR33+T

Overview

MAX6346UR33+T from Maxim Integrated is a precision 3.3V microprocessor supervisory circuit in SOT23-3 package, providing active-low push-pull reset assertion when VCC falls below 3.30V (±1.5% at +25°C), with guaranteed operation down to 1.2V and 100ms minimum reset timeout after power-up. It delivers ultra-low 1µA max supply current and immunity to fast VCC transients, making it ideal for battery-powered embedded controllers requiring reliable brownout detection.

For engineers reviewing the MAX6346UR33+T datasheet, MAX6346UR33+T pinout, MAX6346UR33+T application, or MAX6346UR33+T equivalent, key selection criteria include its factory-trimmed 3.30V reset threshold, push-pull output drive capability (0.3V VOL @ 1.6mA), -40°C to +85°C industrial temperature range, and compatibility with 3.3V µP power rails in space-constrained designs.

Technical Context

The MAX6346UR33+T implements a precision bandgap-based voltage comparator with 40ppm/°C tempco and 9.5mV hysteresis to ensure stable reset assertion during supply fluctuations. Its internal reset timer guarantees ≥100ms reset pulse width after VCC recovery, independent of external components.

Designed for direct integration into 3.3V digital systems, it features rail-to-rail VCC monitoring (1.2V–5.5V operating range), push-pull RESET output capable of sourcing 500µA at 0.8·VCC and sinking 1.6mA at ≤0.3V, and transient immunity validated up to 100V/µs dV/dt on VCC.

Key Specifications

Pinout & Package

MAX6346UR33+T is housed in a 3-pin SOT23-3 package (outline U3-1), with 1.3mm × 2.9mm footprint and 0.95mm height, optimized for high-density PCB layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX809TRD3+T and TPS3808G33DBVR, the MAX6346UR33+T offers the optimal balance of 3.30V-specific accuracy, ultra-low 1µA ICC, and push-pull simplicity-making it preferred for long-life 3.3V embedded controllers where board space and battery runtime are constrained.

Availability

MAX6346UR33+T is available at Aetrix Electronics and suitable for industrial PLC controllers, portable medical monitors, smart energy meters, and IoT edge gateways requiring stable component supply and long-term production continuity.

Supply support for MAX6346UR33+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 precision analog and mixed-signal ICs for industrial, automotive, and communications applications, with emphasis on reliability and low-power operation.

The MAX63xx family targets microprocessor supervision in resource-constrained systems, delivering integrated reset functionality with minimal external components and guaranteed performance across harsh environmental conditions.

FAQ

What is the exact reset threshold voltage of MAX6346UR33+T and how tightly is it specified?

The MAX6346UR33+T has a factory-trimmed nominal reset threshold of 3.30V, specified as ±1.5% at +25°C and ±2.5% over the full -40°C to +85°C operating temperature range. This precision eliminates need for external calibration and ensures reliable brownout detection in 3.3V systems. The device also includes 9.5mV of built-in hysteresis to prevent reset chatter during slow VCC recovery. These values are guaranteed by production test, not just typical performance.

Does MAX6346UR33+T require any external components to function as a reset supervisor?

No, the MAX6346UR33+T operates as a fully self-contained reset supervisor with no external components required. Its internal precision voltage reference, comparator, and reset timer eliminate the need for external resistors, capacitors, or diodes. This reduces BOM cost, PCB area, and design validation effort-particularly valuable in space-constrained applications like portable medical devices and smart meters where the MAX6346UR33+T is commonly deployed.

What is the maximum supply voltage the MAX6346UR33+T can monitor, and down to what VCC level does it remain functional?

The MAX6346UR33+T monitors VCC over a 1.2V to 5.5V range and remains fully functional-including correct reset assertion and release-down to 1.2V across the full -40°C to +85°C temperature range. This extended low-voltage operation ensures robust behavior during deep brownouts and allows use with partially discharged batteries or low-dropout regulator outputs. The device's reset comparator is designed to ignore fast transients, further enhancing reliability in noisy power environments where the MAX6346UR33+T is deployed.

How does the push-pull output of MAX6346UR33+T differ from open-drain alternatives, and what design benefit does it provide?

The MAX6346UR33+T features an active-low push-pull RESET output, meaning it actively drives both logic low (≤0.3V at 1.6mA sink) and logic high (≥0.8·VCC at 500µA source) without requiring an external pull-up resistor. This simplifies µP interface design, reduces component count, and improves noise immunity compared to open-drain variants. In applications like industrial PLCs and IoT gateways, this eliminates potential weak-pull issues and ensures clean, fast reset signal edges-critical for reliable startup of the MAX6346UR33+T's target systems.

Is MAX6346UR33+T compatible with common microprocessor reset input requirements?

Yes, the MAX6346UR33+T is explicitly designed for direct interface with standard µP reset inputs. Its active-low push-pull output meets TTL and CMOS logic level requirements across its full VCC range (1.2V–5.5V), and its 100ms minimum reset pulse width satisfies typical µP power-on initialization timing. The device is also pin-compatible with legacy supervisors like MAX803/MAX809/MAX810, enabling drop-in replacement in existing designs-making MAX6346UR33+T a seamless upgrade path for 3.3V systems requiring improved accuracy and lower power.