Analog Devices Inc./Maxim Integrated MXD1813UR44

Overview

MXD1813UR44 from Maxim Integrated is a low-power microprocessor reset supervisor IC designed for +5V systems, featuring an open-drain active-low RESET output with internal 5.5kΩ pullup resistor, factory-set 4.37V reset threshold (±2.5% over temperature), 100ms minimum reset timeout, and debounced manual-reset detection triggered by ≥1.5μs low pulse on RESET pin. It ensures reliable power-on/power-down reset in portable microcontroller-based equipment.

For engineers reviewing the MXD1813UR44 datasheet, MXD1813UR44 pinout, MXD1813UR44 application, or MXD1813UR44 equivalent, key selection criteria include its 4.37V V_TH, open-drain manual-reset capability, −40°C to +105°C operation, 4μA supply current, and SOT23-3 package compatibility with DS181x-series designs.

Technical Context

The MXD1813UR44 integrates a precision voltage comparator monitoring VCC against a trimmed 4.37V threshold, with built-in immunity to fast transients (e.g., ≤20μs at 100mV overdrive). Its internal timer guarantees RESET remains asserted for ≥100ms after VCC rises above V_TH, and separately initiates a second 100ms timeout when the RESET pin is held low ≥1.5μs - enabling robust mechanical switch interfacing without external debounce circuitry.

This device operates down to VCC = +1V while maintaining valid RESET logic state, uses BiCMOS process for low 4μA quiescent current, and features open-drain output with internal pullup - allowing direct connection to bidirectional μP reset pins (e.g., Motorola 68HC11) without external components.

Key Specifications

Pinout & Package

MXD1813UR44 is housed in a 3-pin SOT23 package (outline U3-1), with 1.3mm × 2.9mm footprint, 0.95mm height, and gull-wing leads. Pin 1 is RESET (open-drain active-low), Pin 2 is VCC (supply input and threshold monitor), and Pin 3 is GND.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX809TR44D and TPS3808G33DBVR, MXD1813UR44 uniquely combines 4.37V threshold, integrated manual-reset debounce, and 4μA supply current in a drop-in SOT23-3 package - making it the only option satisfying all three requirements simultaneously for +5V portable μP systems.

Availability

MXD1813UR44 is available at Aetrix Electronics and suitable for industrial controllers, portable medical devices, set-top boxes, network routers, and battery-powered instrumentation requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MXD1813UR44 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 semiconductor solutions for industrial, communications, and consumer applications.

The MXD1810–MXD1818 family was engineered specifically for cost-sensitive, space-constrained microprocessor reset supervision in portable and embedded 5V/3.3V systems - prioritizing ultra-low power, factory-trimmed accuracy, and integrated manual-reset functionality.

FAQ

What is the exact reset threshold voltage of MXD1813UR44 and how stable is it over temperature?

The MXD1813UR44 has a factory-set reset threshold of 4.37V, with guaranteed accuracy of ±2.5% across the full operating temperature range of −40°C to +105°C. This stability is achieved through laser-trimming during production and BiCMOS process design, ensuring consistent brownout detection in demanding thermal environments without external calibration.

Does MXD1813UR44 support manual reset, and how does its debounce function work?

Yes, MXD1813UR44 supports debounced manual reset: pulling the RESET pin low for ≥1.5μs triggers a guaranteed 100ms reset pulse. Internal circuitry filters mechanical switch bounce, so brief contact closures (<1.5μs) do not initiate reset - eliminating need for external RC networks or firmware polling in applications like field-service buttons.

What package type and pinout does MXD1813UR44 use, and is it compatible with other reset ICs?

MXD1813UR44 uses the standard 3-pin SOT23 package (U3-1 outline) with pin 1 = RESET (open-drain), pin 2 = VCC, pin 3 = GND. It is pin-compatible with the DS181x series and shares footprint and pin assignments with MAX809/MAX810 variants - enabling drop-in replacement in existing layouts designed for those families.

How low can VCC go before MXD1813UR44 stops asserting a valid RESET signal?

MXD1813UR44 guarantees correct RESET logic state down to VCC = +1.0V. Below this, the internal comparator and output stage may become indeterminate. For applications requiring valid RESET down to 0V, a 100kΩ external pulldown resistor on the RESET pin is recommended - though this is rarely needed since most μPs cease operation above +1.0V.

What is the supply current consumption of MXD1813UR44, and how does it compare to similar reset supervisors?

MXD1813UR44 draws only 4μA typical supply current at +3.6V, significantly lower than alternatives like MAX809TR44D (12μA). This ultra-low ICC enables multi-year operation in coin-cell-powered devices and reduces self-heating in thermally constrained enclosures - a key differentiator for portable and battery-backed systems.