Analog Devices Inc./Maxim Integrated MXD1818XR29

Overview

MXD1818XR29 from Maxim Integrated is a low-power microprocessor reset supervisor IC designed for +2.5V/+3.0V/+3.3V digital systems. It provides active-low, open-drain RESET output with manual-reset debouncing, 2.88V factory-set reset threshold (±2.5% over temperature), 100ms minimum reset timeout, and guaranteed operation down to VCC = +1V. It is used in portable battery-powered equipment to ensure reliable μP initialization during power-up, brownout, and push-button events.

For engineers reviewing the MXD1818XR29 datasheet, MXD1818XR29 pinout, MXD1818XR29 application, or MXD1818XR29 equivalent, key selection criteria include reset threshold accuracy, manual-reset debounce timing (1.5μs detection), open-drain output with internal 5.5kΩ pullup, SC70-3 package compatibility, and support for -40°C to +105°C industrial temperature operation.

Technical Context

The MXD1818XR29 implements a precision voltage-monitoring comparator with hysteresis to detect VCC drops below 2.88V and assert RESET within 5μs. Its internal timer guarantees ≥100ms reset assertion after VCC recovery, independent of supply ramp rate.

It integrates debounced manual-reset logic that detects external low pulses on the RESET pin lasting ≥1.5μs and initiates a separate 100ms reset timeout - enabling robust interface with mechanical switches without external RC networks or firmware polling.

Key Specifications

Pinout & Package

MXD1818XR29 is housed in a 3-pin SC70 package (outline X3-2, land pattern 90-0208), optimized for high-density portable designs. 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 supervision applications.

Compared with MAX809TRD29+T and TPS3808G33DBVR, MXD1818XR29 uniquely combines factory-trimmed 2.88V accuracy, integrated 1.5μs debounce, and 4μA quiescent current in SC70 - making it optimal for compact, battery-sensitive designs requiring robust hardware-managed reset.

Availability

MXD1818XR29 is available at Aetrix Electronics and suitable for portable medical sensors, industrial handheld terminals, smart home hub controllers, and IoT edge gateways requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for MXD1818XR29 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 and mixed-signal ICs for power, sensing, and connectivity applications.

The MXD1810–MXD1818 family was designed specifically for cost-sensitive, space-constrained microprocessor reset supervision in portable and industrial systems - emphasizing low power, precision thresholds, and integrated manual-reset functionality.

FAQ

What is the exact reset threshold voltage of the MXD1818XR29 and how tightly is it specified?

The MXD1818XR29 has a factory-set reset threshold of 2.88V, with guaranteed accuracy of ±2.5% over the full operating temperature range of -40°C to +105°C. This specification is confirmed in the Electrical Characteristics table under "MXD181_ _ R29" row, where min/typ/max values are 2.80V/2.88V/2.97V. The threshold is trimmed during production and does not require external calibration. MXD1818XR29 maintains this precision without drift or adjustment across its rated voltage and thermal conditions.

Does the MXD1818XR29 support manual reset, and if so, what are the timing requirements?

Yes, the MXD1818XR29 supports debounced manual reset via its RESET pin. It detects an externally applied low pulse of ≥1.5μs duration and responds with a guaranteed 100ms minimum reset timeout period (tPBRST). This feature is exclusive to the MXD1813/MXD1818 variants and is documented in both the General Description and Electrical Characteristics sections. The internal debounce logic eliminates need for external filtering, making MXD1818XR29 suitable for direct connection to mechanical pushbuttons.

What is the output configuration of the MXD1818XR29 and how does it interface with microcontrollers?

The MXD1818XR29 features an open-drain, active-low RESET output with an internal 5.5kΩ pullup resistor to VCC. This allows direct connection to bidirectional microcontroller reset pins (e.g., ARM Cortex-M, MSP430) without external components. When asserted, the output sinks current; when deasserted, the internal pullup holds RESET high. This configuration is explicitly defined in the Pin Descriptions and Functional Diagram sections for MXD1818, distinguishing it from push-pull variants like MXD1817.

What package type and footprint does the MXD1818XR29 use, and is it RoHS-compliant?

The MXD1818XR29 is supplied in a 3-pin SC70 package (outline X3-2, land pattern 90-0208), measuring 2.0mm × 1.25mm. It is RoHS-compliant, as indicated by the "+T" suffix option in the Ordering Information - though the base part number MXD1818XR29-T uses leaded packaging, and MXD1818XR29+T denotes lead-free. The SC70 footprint is verified in the Package Information section and supported by Maxim's official land pattern documentation.

How low can VCC go while still ensuring valid RESET output behavior for the MXD1818XR29?

The MXD1818XR29 guarantees valid RESET/RESET logic states down to VCC = +1.0V, as stated in the Absolute Maximum Ratings and Electrical Characteristics tables. This is critical for fail-safe operation during deep brownout. However, because it uses an open-drain output with internal pullup, RESET will drift non-active (high-impedance) below ~1.2V - unlike push-pull variants. The datasheet explicitly notes this limitation and confirms MXD1818XR29 is not recommended for applications requiring valid RESET at VCC = 0V.