Analog Devices Inc./Maxim Integrated MAX6348XR45-T

Overview

MAX6348XR45-T from Maxim Integrated is an open-drain, active-low microprocessor supervisory circuit designed to monitor 4.5V power supplies and assert reset during brownout, power-up, and power-down events. It features a factory-trimmed 4.500V 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 operation down to 1.2V VCC. It is used in portable battery-powered systems requiring reliable, low-power reset assertion.

For engineers reviewing the MAX6348XR45-T datasheet, MAX6348XR45-T pinout, MAX6348XR45-T application, or MAX6348XR45-T equivalent, this page provides verified technical context, pin-level design meaning, real-world use scenarios, and validated alternative options for µP reset supervision in space-constrained, low-quiescent-current designs.

Technical Context

The MAX6348XR45-T implements a precision bandgap-based voltage comparator with hysteresis (9.5mV) to detect VCC falling below its 4.500V threshold, triggering an open-drain RESET signal that remains asserted for ≥100ms after VCC recovers. Its internal architecture ensures immunity to fast transients (up to 100V/µs dV/dt) and guarantees correct state down to 1.2V VCC.

As part of the MAX634x family, it shares the same SC70-3 package, 3-pin topology, and ultra-low ICC (≤1.0µA at 3V, ≤1.75µA at 5.5V), but differs from push-pull variants (e.g., MAX6346) by requiring an external pull-up resistor and enabling bidirectional reset interfacing with µPs like the Motorola 68HC11.

Key Specifications

Pinout & Package

MAX6348XR45-T is housed in a 3-pin SC70-3 package (outline X3-2), footprint-compatible with SOT23-3 but 30% smaller. The package supports leaded and lead-free assembly (order with "+T" for RoHS).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6348XR45-T, the MAX6348UR45-T offers identical electrical behavior in a larger, thermally robust package, while the TPS3808G33DBVR provides different functionality (push-pull, enable pin) suited to non-bidirectional µP architectures-neither is pin-compatible, but both serve overlapping supervision roles with distinct trade-offs in size, interface, and feature set.

Availability

MAX6348XR45-T is available at Aetrix Electronics and suitable for portable medical monitors, smart meter data loggers, and industrial PLC I/O modules requiring stable component supply, long-lifecycle assurance, and RoHS-compliant sourcing.

Supply support for MAX6348XR45-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, mixed-signal, and power management ICs for industrial, automotive, and computing applications.

The MAX634x series was developed specifically for ultra-low-power microprocessor reset supervision in battery-critical and space-constrained systems, emphasizing sub-µA quiescent current, factory-trimmed accuracy, and SC70/SOT23 compatibility.

FAQ

What is the exact reset threshold voltage of MAX6348XR45-T and how tightly is it specified?

The MAX6348XR45-T has a nominal reset threshold of 4.500V, factory-trimmed 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 per the Electrical Characteristics table in the official datasheet, and the "R45" suffix explicitly denotes the 4.500V variant within the MAX6348 family.

Does MAX6348XR45-T require an external pull-up resistor on the RESET pin, and why?

Yes, MAX6348XR45-T requires an external pull-up resistor on the RESET pin because it features an open-drain output. The internal transistor only sinks current when asserting reset; the pull-up (typically 10–100kΩ to VCC or another logic rail) provides the high-state voltage level. This design enables wired-OR configurations and direct interfacing with bidirectional µP reset pins such as those found on the Motorola 68HC11.

What is the minimum VCC voltage at which MAX6348XR45-T remains functional and guarantees correct reset state?

MAX6348XR45-T is guaranteed to maintain correct reset state down to 1.2V VCC over the full -40°C to +85°C temperature range. This allows it to supervise power rails during deep brownout conditions or from partially discharged batteries, ensuring reliable reset assertion even as the supply collapses well below its 4.5V threshold.

How does the 100ms minimum reset timeout of MAX6348XR45-T benefit system reliability?

The 100ms minimum reset timeout of MAX6348XR45-T ensures the microprocessor remains held in reset long enough for all internal circuits-including PLLs, memories, and peripherals-to fully stabilize after power recovery. This prevents race conditions, corrupted register states, or undefined boot sequences that could occur if reset were released prematurely, directly improving boot-time reliability in embedded systems.

Is MAX6348XR45-T pin-compatible with older Maxim reset supervisors like MAX809?

Yes, MAX6348XR45-T is pin-compatible with MAX809-series supervisors in the same SC70-3 or SOT23-3 package. Both share identical 3-pin assignments (VCC, RESET, GND) and open-drain active-low output behavior. However, MAX6348XR45-T offers superior specs: lower supply current (1µA vs. ~10µA), tighter threshold accuracy (±1.5% vs. ±2.5%), and guaranteed operation down to 1.2V VCC.