Analog Devices Inc./Maxim Integrated MAX6348XR38-T

Overview

MAX6348XR38-T from Maxim Integrated is an open-drain, active-low microprocessor supervisory circuit designed to monitor VCC supply voltage and assert reset during power-up, brownout, or power-down events. It features a factory-trimmed 3.800V reset threshold (±1.5% at +25°C, ±2.5% over -40°C to +85°C), 100ms minimum reset timeout, ultra-low 1µA max supply current, and operates from 1.2V to 5.5V. It is used in portable battery-powered systems requiring reliable power-on reset with transient immunity.

For engineers reviewing the MAX6348XR38-T datasheet, MAX6348XR38-T pinout, MAX6348XR38-T application, or MAX6348XR38-T equivalent, key selection criteria include open-drain output compatibility with bidirectional µP reset pins (e.g., Motorola 68HC11), 3.8V threshold precision across temperature, SC70-3 package footprint, and immunity to sub-200µs negative-going VCC transients at 3.8V overdrive.

Technical Context

The MAX6348XR38-T implements a precision bandgap-based reset comparator with hysteresis (9.5mV) and internal timing capacitor to guarantee ≥100ms reset assertion after VCC rises above 3.800V. Its open-drain RESET output requires an external pull-up for level translation and supports wired-OR configurations with µP reset pins.

It operates down to 1.2V VCC while maintaining correct reset state, ignores fast VCC transients via built-in noise filtering, and delivers stable performance across -40°C to +85°C with 40ppm/°C reset threshold tempco. No external components are needed beyond the pull-up resistor on RESET.

Key Specifications

Pinout & Package

MAX6348XR38-T is housed in a 3-pin SC70-3 package (outline 21-0075), measuring 2.0mm × 2.1mm × 0.95mm, with gull-wing leads and RoHS-compliant lead-free finish (marked "FZCC").

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6348XR38-T, the MAX6348UR38-T offers identical supervision performance in a larger SOT23-3 package for easier assembly, while the TPS3808G33DBVR trades open-drain versatility for lower quiescent current and fixed 3.3V threshold-making it incompatible with 3.8V monitoring or bidirectional reset requirements.

Availability

MAX6348XR38-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 with guaranteed long-term availability.

Supply support for MAX6348XR38-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 power, sensing, and interface applications in industrial, automotive, and computing markets.

The MAX63xx family delivers ultra-low-power, precision voltage supervision for microprocessor systems, targeting battery-operated and space-constrained applications where reliability, small size, and minimal BOM count are critical.

FAQ

What is the exact reset threshold voltage of MAX6348XR38-T and how does it vary with temperature?

The MAX6348XR38-T has a factory-trimmed nominal reset threshold of 3.800V. At +25°C, this is guaranteed to be within ±1.5% (3.743V to 3.857V). Over the full operating temperature range of -40°C to +85°C, the threshold varies by ±2.5%, resulting in a minimum of 3.705V and maximum of 3.895V. Its 40ppm/°C tempco ensures predictable, linear drift across temperature.

Does MAX6348XR38-T require an external pull-up resistor on the RESET pin, and what value is recommended?

Yes, MAX6348XR38-T requires an external pull-up resistor on its open-drain RESET pin because it cannot drive high actively. A 10kΩ resistor to the target logic rail (e.g., 3.3V or 5V) is typical, ensuring RESET rises quickly while limiting current to ≤100µA when asserted. The device sinks up to 1.6mA when RESET is low, so the resistor must be sized to maintain VOL ≤0.3V under that load.

Can MAX6348XR38-T be used with microcontrollers that have bidirectional reset pins, such as the Motorola 68HC11?

Yes, MAX6348XR38-T is explicitly designed for this use case. Its open-drain RESET output allows direct connection to bidirectional µP reset pins using only one external pull-up resistor. Either the MAX6348XR38-T or the µP can assert reset - for example, the MAX6348XR38-T pulls RESET low during brownout, while the µP can drive it low for software-initiated reset - enabling fully compliant handshake behavior.

What is the minimum VCC voltage at which MAX6348XR38-T guarantees correct reset state assertion?

MAX6348XR38-T guarantees correct reset state (i.e., RESET asserted when VCC < VTH and deasserted only after VCC > VTH for ≥100ms) down to 1.2V over the full -40°C to +85°C temperature range. This ensures reliable operation during deep brownout events where VCC collapses well below nominal levels, unlike many supervisors that fail below 2.0V.

How does MAX6348XR38-T handle fast transients on the VCC supply line?

MAX6348XR38-T incorporates internal noise filtering to reject fast negative-going VCC transients. Its reset comparator is designed to ignore glitches shorter than ~200µs when VCC dips 100mV below the 3.800V threshold. This immunity prevents false resets in electrically noisy environments such as motor drives or switching power supplies, as confirmed by the "Maximum Transient Duration vs. Reset Threshold Overdrive" graph in the datasheet.