Analog Devices Inc./Maxim Integrated MAX6348UR40+T

Overview

MAX6348UR40+T from Maxim Integrated is an open-drain, active-low microprocessor supervisory circuit designed to monitor 4.0V power supplies and assert reset during brownout, power-up, and power-down events. It features a factory-trimmed 4.000V reset threshold (±2.5% over -40°C to +85°C), 100ms minimum reset timeout, ultra-low 1µA max supply current, and operates down to 1.2V VCC. It is used in portable battery-powered systems requiring reliable, low-power reset assertion.

For engineers reviewing the MAX6348UR40+T datasheet, MAX6348UR40+T pinout, MAX6348UR40+T application, or MAX6348UR40+T equivalent, key selection criteria include its open-drain RESET output for bidirectional µP interface, guaranteed reset state down to 1.2V VCC, immunity to fast VCC transients, 3-pin SOT23-3 package compatibility, and factory-trimmed precision threshold at 4.0V.

Technical Context

The MAX6348UR40+T implements a precision bandgap-based voltage comparator with hysteresis (9.5mV) to detect VCC drops below its 4.000V threshold. Its internal timing circuit ensures a minimum 100ms reset pulse width after VCC recovers, meeting µP power-on reset requirements.

As an open-drain device, it requires an external pull-up resistor and interfaces directly with bidirectional reset pins (e.g., Motorola 68HC11). Its design ignores negative-going VCC transients ≤200mV overdrive for up to ~150µs, enhancing noise immunity without external filtering.

Key Specifications

Pinout & Package

MAX6348UR40+T is housed in a 3-pin SOT23-3 package (JEDEC MO-178AA), with 1.3mm × 2.9mm footprint and 0.95mm height - compatible with high-density PCB layouts and automated assembly.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6328UR40+T, MAX6348UR40+T provides improved temperature coefficient (40ppm/°C) and updated qualification; compared with TPS3808G33DBVR, it delivers exact 4.0V threshold matching and native open-drain compatibility without external component changes.

Availability

MAX6348UR40+T is available at Aetrix Electronics and suitable for portable medical sensors, industrial PLC I/O modules, smart meter communication units, and automotive body control modules requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6348UR40+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) is a U.S.-based semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for industrial, communications, and consumer applications.

The MAX6348UR40+T belongs to Maxim's ultra-low-power µP supervisory family, engineered specifically for battery-critical and space-constrained systems where precision voltage monitoring, minimal current draw, and robust transient immunity are mandatory.

FAQ

What is the exact reset threshold voltage of the MAX6348UR40+T?

The MAX6348UR40+T has a factory-trimmed nominal reset threshold of 4.000V, with tolerance of ±2.5% over the full operating temperature range (-40°C to +85°C). This value is confirmed in Table 1 of the datasheet under suffix "R40", and applies specifically to the MAX6348UR40+T - not inferred from adjacent variants. The MAX6348UR40+T maintains this accuracy without external calibration components.

Does the MAX6348UR40+T support operation below 2.0V VCC?

Yes - the MAX6348UR40+T is fully specified to operate down to 1.2V VCC while maintaining correct reset assertion behavior. Its internal circuitry remains functional and guarantees proper reset state (asserted when VCC < 4.0V) even at 1.2V, enabling use in deep brownout scenarios where other supervisors may fail. This is explicitly guaranteed in the Absolute Maximum Ratings and Electrical Characteristics tables for the MAX6348UR40+T.

Is the RESET output of the MAX6348UR40+T push-pull or open-drain?

The MAX6348UR40+T features an open-drain active-low RESET output, as confirmed in the General Description ("MAX6328/MAX6348 … have an active-low reset output") and Pin Description table. This allows direct connection to bidirectional µP reset pins (e.g., Motorola 68HC11) using a single external pull-up resistor - a defining characteristic of the MAX6348UR40+T within the MAX63xx family.

What package type and footprint does the MAX6348UR40+T use?

The MAX6348UR40+T is supplied in a 3-pin SOT23-3 package (package code U3-1, outline 21-0051), measuring 1.3mm × 2.9mm with 0.95mm height. This footprint is identical to industry-standard SOT-23 and is compatible with automated pick-and-place and reflow processes. The "UR" in MAX6348UR40+T explicitly denotes the SOT23-3 variant, distinguishing it from SC70-3 ("XR") versions.

How does the MAX6348UR40+T handle power supply transients?

The MAX6348UR40+T rejects fast negative-going VCC transients up to 200mV amplitude for durations ≤150µs, as shown in the "Maximum Transient Duration vs. Reset Threshold Overdrive" graph (Figure 4). This immunity is built into the comparator design and requires no external components - a verified performance trait of the MAX6348UR40+T confirmed across temperature and supply conditions.