Analog Devices Inc./Maxim Integrated MXD1818XR31-T

Overview

MXD1818XR31-T from Maxim Integrated is an open-drain, active-low microprocessor reset supervisor IC with debounced manual-reset capability, designed for +2.5V/+3.0V/+3.3V systems. It asserts reset when VCC falls below 3.06V (±2.5% over temperature), maintains reset for ≥100ms after VCC recovery or manual trigger, consumes only 4μA typical supply current, and operates from -40°C to +105°C in a 3-pin SC70 package - used in portable battery-powered controllers and set-top boxes.

For engineers reviewing the MXD1818XR31-T datasheet, MXD1818XR31-T pinout, MXD1818XR31-T application, or MXD1818XR31-T equivalent, key selection criteria include its 3.06V factory-set reset threshold, 100ms minimum timeout, internal 5.5kΩ pullup resistor, debounced manual-reset input requiring ≥1.5μs low pulse, and guaranteed RESET validity down to VCC = +1V.

Technical Context

The MXD1818XR31-T implements a precision bandgap-based voltage comparator monitoring VCC against a factory-trimmed 3.06V threshold, with ±2.5% accuracy across -40°C to +105°C. Its internal timer generates a fixed 100ms (min) reset timeout upon VCC rise or manual reset release, and it features dedicated circuitry to detect and debounce external low pulses on the RESET pin.

This device uses BiCMOS process technology and includes an internal 5.5kΩ pullup resistor on the open-drain RESET output, enabling direct interface with bidirectional μP reset pins without external components. It rejects fast VCC transients up to 100μs duration at 200mV overdrive and guarantees correct logic state output down to VCC = +1V.

Key Specifications

Pinout & Package

MXD1818XR31-T is housed in a 3-pin SC70 package (outline X3-2, land pattern 90-0208), with 0.65mm pitch and moisture sensitivity level (MSL) 1. The package is RoHS-compliant and rated for reflow soldering per JEDEC J-STD-020.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MXD1818XR31-T, MAX809TRD33-T offers tighter threshold tolerance but omits manual reset, while TPS3808G33DBVR provides timeout flexibility at the cost of added components and layout area - MXD1818XR31-T delivers integrated debouncing and minimal footprint for cost-sensitive portable designs.

Availability

MXD1818XR31-T is available at Aetrix Electronics and suitable for portable medical monitors, industrial PLC controllers, smart set-top boxes, and wireless sensor nodes requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MXD1818XR31-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 MXD1810–MXD1818 family was designed specifically for low-power, space-constrained microprocessor supervision in battery-operated and thermally demanding systems - emphasizing precision threshold accuracy, zero-external-component operation, and robust manual reset handling.

FAQ

What is the exact reset threshold voltage of the MXD1818XR31-T?

The MXD1818XR31-T has a factory-set reset threshold of 3.06V, with ±2.5% accuracy guaranteed over the full operating temperature range of -40°C to +105°C. This value is confirmed in the Electrical Characteristics table under "MXD181_ _ R31" row, where VTH min = 2.98V, typ = 3.06V, max = 3.15V. The threshold is trimmed during wafer test and does not require external calibration.

Does the MXD1818XR31-T support manual reset, and how does it work?

Yes, the MXD1818XR31-T supports debounced manual reset via its open-drain RESET pin. When the RESET pin is pulled low for ≥1.5μs, the device asserts active-low reset for ≥100ms after the pin is released. Internal circuitry filters mechanical switch bounce, eliminating need for external RC networks. This behavior is exclusive to MXD1813/MXD1818 variants and documented in the "Push-Button Reset" section.

What package type and dimensions does the MXD1818XR31-T use?

The MXD1818XR31-T uses a 3-pin SC70 package (outline X3-2), measuring 2.0mm × 2.1mm × 0.9mm with 0.65mm lead pitch. It is RoHS-compliant and rated MSL 1. The top marking is "AIP", per Table 1. This package is smaller than SOT23 and optimized for high-density portable PCB layouts.

Can the MXD1818XR31-T operate with supply voltages below 2.5V?

Yes, the MXD1818XR31-T operates with VCC from 1.0V to 5.5V. Its reset comparator and output driver remain functional down to VCC = +1V, ensuring valid RESET logic state even during deep brownout conditions. However, the 3.06V threshold is only meaningful when VCC exceeds that level; below 3.06V, the device asserts reset continuously.

Is an external pullup resistor required for the MXD1818XR31-T's RESET pin?

No, an external pullup resistor is not required. The MXD1818XR31-T integrates a 5.5kΩ internal pullup resistor on its open-drain RESET output, enabling direct connection to bidirectional μP reset pins (e.g., Motorola 68HC11) without additional components. This is explicitly stated in the Pin Descriptions and Applications Information sections.