Analog Devices Inc./Maxim Integrated MXD1817UR26+T

Overview

MXD1817UR26+T from Maxim Integrated is a low-power microprocessor reset supervisor IC in SOT23-3 package, featuring active-high push-pull RESET output, factory-set 2.55V reset threshold (±2.5% over temperature), 100ms minimum reset timeout, and operation down to VCC = +1V. It monitors +2.5V/+3.0V/+3.3V power rails in portable and industrial embedded systems to prevent code-execution errors during brownout.

For engineers reviewing the MXD1817UR26+T datasheet, MXD1817UR26+T pinout, MXD1817UR26+T application, or MXD1817UR26+T equivalent, key selection criteria include reset threshold accuracy, manual-reset absence (vs. MXD1818), push-pull drive strength, VCC = 1V validity, and SC70/SOT23 footprint compatibility with DS181x family.

Technical Context

The MXD1817UR26+T implements a precision bandgap-based voltage comparator with hysteresis to detect VCC drops below 2.55V, triggering an active-high reset signal. Its internal timer guarantees ≥100ms assertion after VCC recovery, independent of supply ramp rate.

Unlike MXD1818, it lacks manual-reset debounce circuitry and open-drain configuration - its push-pull output sources 350μA when asserted and sinks 10mA when deasserted, eliminating need for external pullup resistors in μP reset interfaces.

Key Specifications

Pinout & Package

MXD1817UR26+T is housed in a RoHS-compliant, lead(Pb)-free 3-pin SOT23 package (outline U3-1), measuring 2.92mm × 1.3mm × 1.0mm, optimized for high-density PCB layouts and reflow soldering.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX809TRD3+T, MXD1817UR26+T offers 35× lower supply current and tighter threshold accuracy but lacks adjustable trip point; versus TPS3808G01DBVR, it delivers smaller footprint and zero-component integration at the cost of fixed timing and non-adjustable threshold.

Availability

MXD1817UR26+T is available at Aetrix Electronics and suitable for portable medical sensors, industrial PLC I/O modules, smart energy meters, and automotive body control modules requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MXD1817UR26+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, communications, computing, and consumer applications.

The MXD181x family targets cost-sensitive, space-constrained embedded systems needing reliable, low-power power-supply monitoring - specifically engineered for microprocessor reset supervision without external components.

FAQ

What is the exact reset threshold voltage of MXD1817UR26+T and how tightly is it specified?

The MXD1817UR26+T has a factory-set reset threshold of 2.55V, guaranteed between 2.47V (min) and 2.64V (max) over the full -40°C to +105°C temperature range. This ±2.5% tolerance is specified in the Electrical Characteristics table and applies across all operating conditions without derating - critical for consistent brownout response in 2.5V/3.3V systems where MXD1817UR26+T is commonly deployed.

Does MXD1817UR26+T support manual reset functionality like MXD1818?

No, MXD1817UR26+T does not include manual reset debounce circuitry. Unlike MXD1818, which detects and debounces external push-button signals on the RESET pin with a 1.5μs minimum low pulse, MXD1817UR26+T only responds to VCC-supply faults. Its RESET pin is strictly an active-high push-pull output - applying external logic to this pin may damage the device or cause undefined behavior. For manual reset capability, MXD1818UR26+T is the functionally matched variant.

Can MXD1817UR26+T operate reliably when VCC drops below 2.0V?

Yes, MXD1817UR26+T is explicitly guaranteed to maintain valid RESET logic states down to VCC = +1.0V, as confirmed in the Absolute Maximum Ratings and Electrical Characteristics sections. At VCC = +1.2V, the device continues asserting correct active-high reset while consuming only ~9μA. This feature ensures deterministic microcontroller reset recovery during deep brownout events where other supervisors fail - a key differentiator of MXD1817UR26+T in mission-critical embedded applications.

What is the maximum sink current capability of the RESET output on MXD1817UR26+T?

The RESET output of MXD1817UR26+T sinks 10mA when deasserted (i.e., pulled low), measured at VOUT = 0.4V and VCC ≥ 2.7V. This is specified in the Electrical Characteristics table under "RESET Output Sink Current (IOL)" for MXD1812/MXD1817 variants. The 10mA drive strength allows direct interfacing with standard CMOS and TTL inputs without external buffers - a design advantage over open-drain alternatives that require pullup resistors and offer lower sink capability.

Is MXD1817UR26+T pin-compatible with older DS181x-series reset ICs?

Yes, MXD1817UR26+T is pin-compatible with the DS181x family (e.g., DS1812, DS1817) in SOT23-3 packaging, as explicitly stated in the Features section ("Pin Compatible with DS181_ Products (SOT23)"). Pin 1 is RESET (active-high push-pull), Pin 2 is VCC, and Pin 3 is GND - identical mapping and electrical behavior enable drop-in replacement in existing layouts without redesign. MXD1817UR26+T improves upon DS181x with tighter threshold accuracy (±2.5% vs. ±3.5%) and lower supply current (4μA vs. ~10μA).