Analog Devices Inc./Maxim Integrated MXD1816XR31+T

Overview

MXD1816XR31+T from Maxim Integrated is an open-drain, active-low microprocessor reset supervisor IC designed for +2.5V/+3.0V/+3.3V systems. It monitors VCC and asserts RESET when supply voltage falls below 3.06V (±2.5%), maintains reset for ≥100ms after VCC recovery, consumes only 4μA typical supply current, and features an internal 5.5kΩ pullup resistor - ideal for portable battery-powered microcontroller power-up sequencing.

For engineers reviewing the MXD1816XR31+T datasheet, MXD1816XR31+T pinout, MXD1816XR31+T application, or MXD1816XR31+T equivalent, key selection criteria include its 3.06V factory-trimmed reset threshold, SC70-3 package footprint, open-drain output compatibility with bidirectional μP reset pins (e.g., Motorola 68HC11), and guaranteed RESET validity down to VCC = +1V.

Technical Context

The MXD1816XR31+T implements a precision bandgap-based voltage comparator with hysteresis to detect VCC drops below 3.06V, coupled with a monolithic timer that enforces a minimum 100ms reset timeout period upon VCC recovery. Its open-drain output architecture eliminates need for external pullup resistors in standard μP interface configurations.

This device belongs to the MXD1815–MXD1818 subfamily optimized for low-voltage systems (2.5V/3.0V/3.3V), excludes manual-reset debouncing circuitry (unlike MXD1818), and uses BiCMOS process technology to achieve 4μA quiescent current and ±2.5% threshold accuracy over –40°C to +105°C.

Key Specifications

Pinout & Package

MXD1816XR31+T is housed in a 3-pin SC70 package (outline X3-2, land pattern 90-0208), measuring 1.25mm × 1.65mm × 0.95mm, rated for –40°C to +105°C operation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MXD1816XR31+T, MAX809TRD3+T trades integrated pullup for lower quiescent current and SOT23 compatibility, while TPS3808G30DBVR adds configurability at the cost of package size and external component dependency - making MXD1816XR31+T optimal for compact, low-BOM-count 3.3V portable designs.

Availability

MXD1816XR31+T is available at Aetrix Electronics and suitable for portable medical sensors, industrial PLC I/O modules, smart energy meters, and wireless sensor nodes requiring stable component supply, long-lifecycle assurance, and RoHS-compliant lead-free packaging.

Supply support for MXD1816XR31+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 semiconductor company specializing in analog, mixed-signal, and power-management ICs for industrial, communications, and consumer applications.

MXD1816XR31+T belongs to the MXD1815–MXD1818 family of low-power μP reset supervisors engineered specifically for reliable power-on/brownout detection in space-constrained 2.5V/3.0V/3.3V embedded systems.

FAQ

What is the exact reset threshold voltage of MXD1816XR31+T and how tightly is it specified?

The MXD1816XR31+T has a factory-set reset threshold of 3.06V, with guaranteed accuracy of ±2.5% 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, with min/typ/max values of 2.98V/3.06V/3.15V. The threshold is trimmed during production and does not require external adjustment.

Does MXD1816XR31+T include an internal pullup resistor, and what is its nominal value?

Yes, MXD1816XR31+T includes an internal pullup resistor on its open-drain RESET pin, with a nominal value of 5.5kΩ (min 3.5kΩ, max 7.5kΩ). This is explicitly stated in the Electrical Characteristics table under "Internal Pullup Resistor, Open-Drain" for "MXD1816", eliminating the need for an external pullup resistor in standard microprocessor interface configurations.

Is MXD1816XR31+T compatible with bidirectional microprocessor reset pins such as those found on the Motorola 68HC11?

Yes, MXD1816XR31+T is explicitly designed for this use case. Its open-drain, active-low RESET output allows direct connection to bidirectional μP reset pins without external components. The Applications Information section confirms compatibility with the Motorola 68HC11 and illustrates the interface in Figure 7, noting that no external pullup is required due to the internal 5.5kΩ resistor.

What is the minimum supply voltage at which MXD1816XR31+T guarantees valid RESET output logic states?

MXD1816XR31+T guarantees valid RESET output logic states down to VCC = +1V, as stated in both the General Description ("guaranteed to output the correct logic state for VCC down to +1V") and Absolute Maximum Ratings table. This ensures deterministic reset behavior during deep brownout conditions common in battery-powered systems.

Does MXD1816XR31+T support manual reset functionality via an external pushbutton?

No, MXD1816XR31+T does not support manual reset. Manual reset with debounced detection is exclusive to the MXD1813 and MXD1818 variants (as confirmed in the General Description and Selector Guide). MXD1816XR31+T is functionally identical to MXD1811 - an open-drain, active-low reset supervisor without pushbutton input capability.