Analog Devices Inc./Maxim Integrated MXD1818XR31

Overview

MXD1818XR31 from Maxim Integrated is a low-power, open-drain, active-low microprocessor reset IC with manual-reset debouncing, designed for +2.5V/+3.0V/+3.3V systems. It asserts reset when VCC falls below 3.06V (±2.5%), maintains reset for ≥100ms after VCC recovery, and detects external push-button resets held >1.5μs - used in portable battery-powered controllers and embedded μP monitoring.

For engineers reviewing the MXD1818XR31 datasheet, MXD1818XR31 pinout, MXD1818XR31 application, or MXD1818XR31 equivalent, key selection criteria include its 3.06V factory-trimmed threshold, SC70-3 package, 4μA supply current, debounced manual-reset input, and guaranteed RESET validity down to VCC = +1V.

Technical Context

The MXD1818XR31 integrates a precision voltage comparator with hysteresis, an internal 5.5kΩ pullup resistor on the open-drain RESET output, and a dedicated manual-reset detection circuit that triggers only on signals held low ≥1.5μs. Its reset timeout timer is fixed at ≥100ms and immune to transients <100μs at 3.06V overdrive.

This device operates across -40°C to +105°C with supply voltage range 1.2V–5.5V, guarantees correct logic state down to VCC = +1V, and rejects fast VCC glitches via built-in transient immunity - enabling reliable brownout and power-cycle supervision without external components.

Key Specifications

Pinout & Package

MXD1818XR31 is housed in a 3-pin SC70 package (outline X3-2), with 0.65mm pitch, 0.9mm max height, and RoHS-compliant lead-free construction. Pin 1 is RESET (open-drain, active-low), Pin 2 is VCC (supply and threshold monitor input), and Pin 3 is GND.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX809TR31D3T and TPS3808G33DBVR, MXD1818XR31 uniquely combines factory-trimmed 3.06V accuracy, integrated debounced manual reset, and SC70-3 footprint - delivering highest integration density and lowest component count for space-constrained 3.3V μP systems.

Availability

MXD1818XR31 is available at Aetrix Electronics and suitable for industrial controller monitoring, portable medical device power supervision, set-top box firmware recovery, and smart sensor node watchdog interface requiring stable component supply across extended temperature ranges.

Supply support for MXD1818XR31 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 semiconductor company specializing in high-performance analog, mixed-signal, and power-management ICs for industrial, computing, and communications markets.

The MXD1810–MXD1818 family was designed specifically for low-power, space-constrained microprocessor reset supervision in battery-operated and thermally demanding embedded systems - emphasizing integration, accuracy, and transient immunity.

FAQ

What is the exact reset threshold voltage of MXD1818XR31 and how tightly is it specified?

The MXD1818XR31 has a factory-set reset threshold of 3.06V with ±2.5% accuracy over the full -40°C to +105°C operating temperature range. This value is trimmed during production and guaranteed per Electrical Characteristics table; typical variation is ±1.5% at +25°C. The "R31" suffix explicitly denotes this 3.06V variant within the MXD1815–MXD1818 series.

Does MXD1818XR31 support manual reset, and how does its debouncing work?

Yes, MXD1818XR31 supports debounced manual reset via its RESET pin: a low pulse ≥1.5μs triggers a guaranteed ≥100ms reset assertion upon release. Internal circuitry filters out mechanical switch bounce shorter than 1.5μs, eliminating need for external RC networks. This feature is exclusive to MXD1813/MXD1818 variants and confirmed in Pin Descriptions and Detailed Description sections.

What package type and footprint does MXD1818XR31 use, and is it RoHS-compliant?

MXD1818XR31 uses the 3-pin SC70 package (outline X3-2), measuring 2.0mm × 1.25mm with 0.65mm lead pitch. It is RoHS-compliant and available in lead-free form (denoted by "+T" suffix); the standard "-T" ordering code indicates leaded packaging. Land pattern number 90-0208 applies, and full mechanical drawings are published on maximintegrated.com/packages.

Can MXD1818XR31 operate reliably at very low supply voltages, and down to what level?

Yes, MXD1818XR31 guarantees correct RESET/RESET logic state down to VCC = +1V, and functions across 1.2V to 5.5V. Its internal comparator and output stage remain fully operational at 1.2V, enabling deterministic reset assertion during deep brownout - critical for preserving data integrity in battery-powered systems approaching end-of-life voltage.

How does the internal pullup resistor on MXD1818XR31's RESET pin affect interfacing with microcontrollers?

The MXD1818XR31 includes a factory-tuned 5.5kΩ internal pullup resistor on its open-drain RESET pin, allowing direct connection to bidirectional μP reset inputs (e.g., Motorola 68HC11) without external components. This eliminates BOM items and layout area while ensuring proper high-state termination - confirmed in Pin Descriptions and Applications Information sections.