Analog Devices Inc./Maxim Integrated MXD1811XR46+T

Overview

MXD1811XR46+T from Maxim Integrated is an open-drain, active-low microprocessor reset supervisor IC designed for +5V systems. It monitors VCC and asserts RESET when voltage falls below 4.62V, holds reset for ≥100ms after recovery, and includes internal 5.5kΩ pullup. Used in portable equipment, printers, and set-top boxes to prevent code-execution errors during brownout.

For engineers reviewing the MXD1811XR46+T datasheet, MXD1811XR46+T pinout, MXD1811XR46+T application, or MXD1811XR46+T equivalent, key selection factors include its 4.62V reset threshold, SC70-3 package, 4μA supply current, open-drain output compatibility with bidirectional μP reset pins, and guaranteed operation down to VCC = +1V.

Technical Context

The MXD1811XR46+T implements a precision bandgap-based reset comparator with ±2.5% threshold accuracy over –40°C to +105°C, immune to fast VCC transients up to 100µs at 100mV overdrive. Its internal timer ensures minimum 100ms reset timeout on VCC rise, independent of temperature or supply variation.

As an open-drain device, it interfaces directly with microcontrollers like the Motorola 68HC11 without external pullup; the integrated 5.5kΩ resistor pulls RESET high when not asserted. It does not support manual reset detection-only MXD1813/MXD1818 variants include debounced push-button functionality.

Key Specifications

Pinout & Package

MXD1811XR46+T is housed in a 3-pin SC70 package (outline X3-2), footprint-compatible with SOT23 but 30% smaller. Pin 1 = RESET (open-drain active-low), Pin 2 = VCC (supply and threshold monitor input), Pin 3 = GND.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX809TRD3+T, MXD1811XR46+T offers SC70 space savings and higher drive strength (10mA sink vs. 20µA), while TPS3808G33DBVR serves a different voltage domain entirely and introduces layout complexity with external timing components.

Availability

MXD1811XR46+T is available at Aetrix Electronics and suitable for printers, set-top boxes, portable/battery-powered equipment, critical μP monitoring, and industrial controllers requiring stable component supply across extended temperature ranges.

Supply support for MXD1811XR46+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) designs precision analog and mixed-signal ICs for industrial, computing, and communications applications.

The MXD1810–MXD1818 family delivers low-power, factory-trimmed reset supervision for microprocessor-based systems, targeting space-constrained and battery-sensitive designs needing guaranteed brownout immunity and minimal external components.

FAQ

What is the exact reset threshold voltage of MXD1811XR46+T, and how tightly is it specified?

The MXD1811XR46+T has a factory-set reset threshold of 4.62V, with a guaranteed tolerance of ±2.5% over the full operating temperature range (–40°C to +105°C). This value is confirmed in the Electrical Characteristics table under "Reset Threshold (VTH)" for suffix R46. The typical value is 4.62V, min 4.50V, max 4.75V at TA = +25°C. MXD1811XR46+T maintains this accuracy without external calibration.

Does MXD1811XR46+T support manual reset via an external pushbutton?

No, MXD1811XR46+T does not support manual reset detection. Only MXD1813 and MXD1818 variants in the same family include debounced manual-reset functionality triggered by a >1.5µs low pulse on the RESET pin. MXD1811XR46+T is a dedicated power-monitoring reset supervisor with no input for external reset initiation.

What package type and dimensions does MXD1811XR46+T use, and is it RoHS-compliant?

MXD1811XR46+T uses the 3-pin SC70 package (outline X3-2), measuring 2.0mm × 1.25mm × 0.9mm with 0.65mm lead pitch. The "+T" suffix explicitly denotes lead(Pb)-free, RoHS-compliant packaging per Maxim's ordering convention. Land pattern number 90-0208 applies for PCB layout.

Can MXD1811XR46+T operate reliably when VCC drops below 2.0V?

Yes, MXD1811XR46+T is guaranteed to maintain correct RESET logic state down to VCC = +1.0V, as stated in the Absolute Maximum Ratings and Electrical Characteristics. However, its open-drain output relies on the internal pullup to VCC; below ~1.5V, sinking capability degrades, so it is not recommended for applications requiring valid RESET assertion at VCC < +1.2V. MXD1811XR46+T meets this spec across –40°C to +105°C.

How does the internal 5.5kΩ pullup resistor in MXD1811XR46+T affect interfacing with a microcontroller's bidirectional reset pin?

The internal 5.5kΩ pullup ensures RESET is actively pulled high when not asserted, enabling direct connection to bidirectional μP reset pins (e.g., Motorola 68HC11) without external components. When the μP drives RESET low, MXD1811XR46+T's open-drain output sinks current cleanly. This eliminates risk of bus contention and reduces component count - a key design advantage confirmed in the Applications Information section. MXD1811XR46+T fully supports this interface mode.