Analog Devices Inc./Maxim Integrated MXD1810UR44

Overview

MXD1810UR44 from Maxim Integrated is a precision +5V microprocessor reset supervisor IC with active-low open-drain RESET output, 4.37V factory-trimmed reset threshold (±2.5% over temperature), 100ms minimum reset timeout, and 4μA supply current. It monitors VCC in industrial embedded systems and asserts reset during brownout or power-up to prevent μP code-execution errors.

For engineers reviewing the MXD1810UR44 datasheet, MXD1810UR44 pinout, MXD1810UR44 application, or MXD1810UR44 equivalent, key selection criteria include its 4.37V threshold accuracy, SOT23-3 package compatibility, open-drain interface for bidirectional μP reset pins, and guaranteed RESET validity down to VCC = +1V - critical for reliable boot sequencing in portable and industrial equipment.

Technical Context

The MXD1810UR44 implements a precision bandgap-based voltage comparator with hysteresis to detect VCC drops below 4.37V, triggering an internal monostable timer that holds RESET low for ≥100ms after VCC recovers. Its open-drain output includes a 5.5kΩ internal pullup resistor, eliminating external components while enabling direct interfacing with bidirectional μP reset inputs like those on Motorola 68HC11.

It features transient immunity against negative-going VCC glitches up to 100µs at 100mV overdrive, operates across -40°C to +105°C, and maintains functional reset assertion even as VCC declines to +1V - ensuring deterministic behavior during deep brownout conditions without external biasing.

Key Specifications

Pinout & Package

MXD1810UR44 is housed in a 3-pin SOT23 package (outline U3-1), with 1.3mm pitch, 2.9mm × 1.6mm body, and Gull-wing leads suitable for reflow soldering. 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 MAX809TRD3-T, MXD1810UR44 offers lower power (4μA vs. 20μA) and integrated pullup for bidirectional reset buses; compared with TPS3808G33DBVR, it provides fixed 4.37V threshold and SOT23-3 pinout essential for legacy +5V μP designs without layout changes.

Availability

MXD1810UR44 is available at Aetrix Electronics and suitable for industrial controllers, portable test equipment, network edge routers, and medical diagnostic sensors requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MXD1810UR44 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, automotive, and communications applications, with expertise in power management, sensing, and interface solutions.

The MXD1810–MXD1818 family targets cost-sensitive, space-constrained embedded systems requiring reliable, low-power reset supervision for +5V and +3.3V microprocessors - emphasizing factory-trimmed accuracy, minimal external components, and extended temperature operation.

FAQ

What is the exact reset threshold voltage of MXD1810UR44 and how tightly is it specified?

The MXD1810UR44 has a factory-set reset threshold of 4.37V, with guaranteed accuracy of ±2.5% over the full operating temperature range (-40°C to +105°C). This specification is confirmed in the Electrical Characteristics table of the official Maxim datasheet, where VTH for suffix "R44" is listed as 4.25V (min), 4.37V (typ), and 4.49V (max) - ensuring predictable brownout response in +5V systems without calibration.

Does MXD1810UR44 support manual reset via an external pushbutton?

No, MXD1810UR44 does not support manual reset. Only MXD1813 and MXD1818 variants in the same family include debounced manual-reset detection on the RESET pin. The MXD1810UR44 is configured as an open-drain active-low supervisor with automatic VCC monitoring only - its RESET pin is output-only and lacks input functionality for external trigger signals.

Can MXD1810UR44 be used with microprocessors that have bidirectional reset pins?

Yes, MXD1810UR44 is explicitly designed for this use case. Its open-drain RESET output with internal 5.5kΩ pullup resistor allows direct connection to bidirectional μP reset pins (e.g., Motorola 68HC11) without external components. The datasheet confirms this in the Applications Information section, stating that either the μP or the MXD1810UR44 can assert reset on the shared line - enabling flexible system-level reset arbitration.

What is the minimum VCC level at which MXD1810UR44 guarantees valid RESET output logic states?

MXD1810UR44 guarantees valid RESET/RESET logic states down to VCC = +1.0V, as stated in both the General Description and Electrical Characteristics sections. This means the output remains deterministically high (via internal pullup) or low (when asserted) even as supply voltage collapses - a critical feature for preventing μP lockup during deep brownout conditions in industrial and portable equipment.

Is MXD1810UR44 pin-compatible with industry-standard reset supervisors like the DS181x series?

Yes, MXD1810UR44 is pin-compatible with DS181x products in SOT23-3 packages, as explicitly noted in the Features section of the datasheet ("Pin Compatible with DS181_ Products (SOT23)"). This compatibility applies to physical pinout (RESET-VCC-GND), allowing drop-in replacement in existing layouts designed for DS1810/DS1811, provided the 4.37V threshold and open-drain output meet system requirements.