Analog Devices Inc./Maxim Integrated MAX6346XR44-T

Overview

MAX6346XR44-T from Maxim Integrated is a precision active-low push-pull microprocessor supervisory circuit designed to monitor 4.38V power supplies and assert reset during brownout, power-up, and power-down events. It delivers 1µA max supply current, 100ms min reset timeout, ±2.5% reset threshold accuracy over -40°C to +85°C, and operates down to 1.2V VCC. It is used in portable battery-powered systems requiring reliable, low-power reset control.

For engineers reviewing the MAX6346XR44-T datasheet, MAX6346XR44-T pinout, MAX6346XR44-T application, or MAX6346XR44-T equivalent, key selection criteria include its factory-trimmed 4.38V reset threshold, SC70-3 package, push-pull active-low output, ultra-low ICC, and immunity to sub-200µs VCC transients - all critical for embedded µP power monitoring in space-constrained designs.

Technical Context

The MAX6346XR44-T implements a precision bandgap-based voltage comparator with 40ppm/°C tempco and 9.5mV hysteresis to detect VCC drops below 4.38V (±2.5% over temperature). Its internal timing circuit guarantees ≥100ms reset assertion after VCC recovers above threshold, independent of supply ramp rate.

It features push-pull RESET output capable of sourcing 500µA at 0.8·VCC and sinking 1.6mA at ≤0.3V, enabling direct interface with µP reset inputs without external pull-ups. The device remains functional down to 1.2V VCC and rejects fast transients via built-in noise immunity circuitry.

Key Specifications

Pinout & Package

MAX6346XR44-T is housed in a 3-pin SC70-3 package (outline X3-2), footprint-compatible with SOT23-3 but 30% smaller. Pin 1 = GND, Pin 2 = RESET (active-low push-pull), Pin 3 = VCC.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6326XR44-T, MAX6346XR44-T adds guaranteed operation to +85°C and tighter tempco; compared with TPS3808G33DBVR, it provides exact 4.38V detection, lower ICC, and push-pull drive - making it the sole drop-in solution for legacy 4.5V-rail µP systems needing long-term reliability.

Availability

MAX6346XR44-T is available at Aetrix Electronics and suitable for battery-powered medical sensors, industrial PLC I/O modules, and portable test equipment requiring stable component supply, long-lifecycle support, and RoHS-compliant packaging.

Supply support for MAX6346XR44-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, medical, and communications applications.

The MAX6346XR44-T belongs to the MAX63xx family of ultra-low-power µP supervisors, engineered specifically for reliable power-monitoring in space-constrained, battery-operated, and wide-temperature embedded systems.

FAQ

What is the exact reset threshold voltage of MAX6346XR44-T and how tightly is it specified?

The MAX6346XR44-T has a factory-trimmed reset threshold of 4.38V, with ±1.5% tolerance at +25°C and ±2.5% over the full -40°C to +85°C operating temperature range. This specification is guaranteed by production testing per the Electrical Characteristics table in the official datasheet, and the 40ppm/°C tempco ensures minimal drift across temperature. The "R44" suffix explicitly denotes the 4.38V variant within the MAX6346 family.

Does MAX6346XR44-T require an external pull-up resistor on its RESET pin?

No, MAX6346XR44-T does not require an external pull-up resistor because it features a push-pull active-low RESET output. The internal driver can source up to 500µA at 0.8·VCC and sink up to 1.6mA at ≤0.3V, allowing direct connection to standard µP reset inputs. This eliminates BOM cost and PCB layout complexity associated with open-drain alternatives like MAX6348XR44-T.

What is the minimum VCC voltage at which MAX6346XR44-T remains functional and asserts reset correctly?

MAX6346XR44-T is fully specified to operate down to 1.2V VCC over the full -40°C to +85°C temperature range. Below 1.2V, the device may not guarantee correct reset assertion or timing; however, the datasheet confirms correct state retention (i.e., RESET remains asserted) for VCC as low as 1.0V at +25°C. This ensures fail-safe behavior during deep brownout conditions common in battery-depleted systems.

How does MAX6346XR44-T handle fast voltage transients on the VCC line?

MAX6346XR44-T incorporates internal transient immunity circuitry that ignores negative-going VCC glitches shorter than ~200µs when the overdrive (VTH – VCC) is 100mV, as shown in the Typical Operating Characteristics graph "Maximum Transient Duration vs. Reset Threshold Overdrive". This prevents false resets caused by switching noise or ESD-induced dips, while still responding reliably to sustained brownouts.

Is MAX6346XR44-T pin-compatible with older Maxim supervisors like MAX809 or MAX810?

Yes, MAX6346XR44-T is pin-compatible with MAX809 and MAX810 in the same SC70-3 or SOT23-3 packages - sharing identical 3-pin assignments (GND, RESET, VCC) and electrical interface. However, MAX6346XR44-T offers superior specs: 1µA vs. 20µA supply current, ±2.5% vs. ±2.8% threshold accuracy, and guaranteed operation down to 1.2V VCC. No PCB changes are needed for drop-in replacement in existing designs using those legacy parts.