Analog Devices Inc./Maxim Integrated MXD1817UR29+T

Overview

MXD1817UR29+T from Maxim Integrated is a low-power microprocessor reset supervisor IC in SOT23-3 package, designed to monitor +2.5V/+3.0V/+3.3V supply rails and assert an active-high push-pull RESET signal when VCC drops below 2.88V (±2.5% accuracy), with guaranteed operation down to VCC = +1V and 100ms minimum reset timeout. It serves as a system-level power-on reset and brownout detector in portable embedded controllers.

For engineers reviewing the MXD1817UR29+T datasheet, MXD1817UR29+T pinout, MXD1817UR29+T application, or MXD1817UR29+T equivalent, key selection criteria include its active-high push-pull output, factory-trimmed 2.88V threshold, -40°C to +105°C operating range, 4μA supply current, and compatibility with battery-powered μP systems requiring deterministic reset timing without external components.

Technical Context

The MXD1817UR29+T implements a precision bandgap-based voltage comparator with hysteresis to detect VCC falling below 2.88V, triggering an internal timer that holds RESET high for ≥100ms after VCC recovers above threshold. Its push-pull output drives logic-high directly without pullup, eliminating external biasing.

Unlike open-drain variants (e.g., MXD1818), MXD1817UR29+T lacks manual-reset debounce circuitry and does not support external pushbutton assertion - it responds only to VCC monitoring. It guarantees valid RESET output down to VCC = +1V, enabling robust reset behavior during deep brownout conditions.

Key Specifications

Pinout & Package

MXD1817UR29+T is housed in a 3-pin SOT23 package (outline U3-1) with gull-wing leads, optimized for automated assembly and thermal performance in space-constrained applications.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MXD1817UR29+T, MAX809TRD29+T saves ~2.4μA but forces redesign of reset interface due to active-low/open-drain behavior, while TPS3808G33DBVR offers superior accuracy and flexibility at 4× higher supply current and different threshold - making MXD1817UR29+T optimal for cost-sensitive, space-constrained 3.3V systems needing simple, low-power, active-high reset.

Availability

MXD1817UR29+T is available at Aetrix Electronics and suitable for portable medical sensors, industrial PLC I/O modules, smart energy meters, and automotive body control units requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MXD1817UR29+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 high-performance analog, mixed-signal, and power management ICs for industrial, communications, and consumer applications.

The MXD1810–MXD1818 family was engineered specifically for low-cost, space-efficient microprocessor reset supervision in battery-powered and thermally demanding embedded systems, emphasizing precision thresholding, minimal external components, and wide-temperature reliability.

FAQ

What is the exact reset threshold voltage of MXD1817UR29+T and how tightly is it specified?

The MXD1817UR29+T has a factory-set reset threshold of 2.88V with ±2.5% accuracy over the full -40°C to +105°C operating temperature range. This specification is guaranteed by design and verified in production testing at +25°C, with limits extrapolated across temperature per Maxim's characterization data. The "R29" suffix in MXD1817UR29+T explicitly denotes this 2.88V threshold variant.

Does MXD1817UR29+T support manual reset via an external pushbutton?

No, MXD1817UR29+T does not support manual reset. It is a VCC-only monitoring device with no internal debounce circuitry or dedicated manual-reset input. Unlike the MXD1813/MXD1818 variants (which feature RESET pin debouncing), MXD1817UR29+T asserts reset solely based on VCC falling below 2.88V and holds it for ≥100ms after recovery. External pushbutton functionality requires a separate circuit or a different part such as MXD1818UR29+T.

What is the output configuration of MXD1817UR29+T and why does it matter for system design?

MXD1817UR29+T features an active-high push-pull RESET output. This means it actively drives the RESET line high during reset and pulls it low when deasserted - eliminating the need for an external pullup resistor. This simplifies PCB layout, reduces BOM count, improves noise immunity compared to open-drain outputs, and ensures fast, strong logic transitions critical for reliable μP initialization in high-speed digital systems.

Can MXD1817UR29+T operate reliably when the supply voltage drops below 2.0V?

Yes, MXD1817UR29+T is guaranteed to maintain valid RESET logic states down to VCC = +1.0V. Its internal comparator and output stage remain functional throughout this range, ensuring deterministic reset behavior during deep brownout events - a key advantage over many competing supervisors that lose output validity below ~1.8V. This capability is explicitly confirmed in the Absolute Maximum Ratings and Electrical Characteristics tables of the datasheet.

Is MXD1817UR29+T pin-compatible with other devices in the MXD181x family?

Yes, all MXD181x devices - including MXD1817UR29+T - share identical 3-pin SOT23 (U3-1) and SC70 (X3-2) footprints. Pin 1 is RESET, Pin 2 is VCC, and Pin 3 is GND across the entire family. This allows direct substitution between variants (e.g., MXD1815UR29+T, MXD1818UR29+T) without PCB layout changes, provided the functional differences - such as output polarity, manual reset support, and threshold voltage - are accounted for in firmware and system timing analysis.