Analog Devices Inc./Maxim Integrated MXD1815XR26+T

Overview

MXD1815XR26+T 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 factory-trimmed 2.55V reset threshold (±2.5% over temperature), 100ms minimum reset timeout, and operates from -40°C to +105°C in SC70-3 package. It monitors VCC supply integrity and asserts reset during brownout or power-up.

For engineers reviewing the MXD1815XR26+T datasheet, MXD1815XR26+T pinout, MXD1815XR26+T application, or MXD1815XR26+T equivalent, key selection criteria include its 2.55V threshold accuracy, 4µA quiescent current, manual-reset debounce capability (not applicable to this variant), open-drain output with internal 5.5kΩ pullup, and compatibility with portable/battery-powered μP systems requiring reliable power-on reset.

Technical Context

The MXD1815XR26+T implements a precision bandgap-based voltage comparator to monitor VCC against a fixed 2.55V threshold. Its internal timer guarantees ≥100ms reset assertion after VCC rises above threshold, independent of supply ramp rate. The device uses BiCMOS process for low 4µA supply current and stable operation down to VCC = +1.0V.

Unlike MXD1813/MXD1818 variants, MXD1815XR26+T lacks manual-reset input detection and debouncing circuitry. Its open-drain RESET output includes an internal 5.5kΩ pullup resistor, enabling direct interface with bidirectional μP reset pins without external components.

Key Specifications

Pinout & Package

MXD1815XR26+T is housed in a 3-pin SC70 package (outline X3-2), measuring 2.0mm × 1.25mm × 0.95mm, suitable for space-constrained PCB layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MXD1815XR26+T, MAX809TRD3+T offers higher reset voltage and SOT23 packaging but lacks SC70 size advantage; TPS3808G125DBVR delivers identical threshold and lower current but adds manual reset and requires PCB redesign for 5-pin placement.

Availability

MXD1815XR26+T is available at Aetrix Electronics and suitable for industrial controllers, portable instrumentation, set-top boxes, and battery-powered microprocessor systems requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MXD1815XR26+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, and computing applications.

The MXD1815XR26+T belongs to the MXD1815–MXD1818 family of low-power μP reset supervisors targeting compact, battery-sensitive 2.5V/3.0V/3.3V systems requiring accurate voltage monitoring and minimal footprint.

FAQ

What is the exact reset threshold voltage of MXD1815XR26+T and how tightly is it specified?

The MXD1815XR26+T has a factory-set reset threshold of 2.55V, guaranteed over the full operating temperature range (-40°C to +105°C) with ±2.5% accuracy. This means the actual threshold falls between 2.47V and 2.64V under all conditions, as confirmed in the Electrical Characteristics table. The "R26" suffix explicitly denotes this 2.55V variant, and the value is trimmed during production using Maxim's BiCMOS process.

Does MXD1815XR26+T support manual reset functionality via the RESET pin?

No, MXD1815XR26+T does not support manual reset detection. Only MXD1813 and MXD1818 variants in the family include debounced manual-reset circuitry that triggers on a 1.5µs low pulse to the RESET pin. MXD1815XR26+T uses the RESET pin solely as an open-drain output - it is not an input and cannot initiate reset externally. This is confirmed in the Pin Descriptions and Functional Diagram sections.

What package type and dimensions does MXD1815XR26+T use, and is it RoHS-compliant?

MXD1815XR26+T is supplied in a 3-pin SC70 package (outline X3-2), measuring 2.0mm × 1.25mm × 0.95mm. The "+T" suffix explicitly indicates lead(Pb)-free, RoHS-compliant packaging per Maxim's ordering conventions. Land pattern information is documented in Maxim's package database under land pattern no. 90-0208, and the device meets JEDEC standards for SC70-3 footprint compatibility.

How does the open-drain RESET output of MXD1815XR26+T interface with a microcontroller that has a bidirectional reset pin?

The MXD1815XR26+T's open-drain RESET output interfaces directly with bidirectional μP reset pins (e.g., Motorola 68HC11) because its internal 5.5kΩ pullup resistor establishes a defined high state when not actively pulled low. This eliminates the need for an external pullup. When the μP asserts reset, it drives the shared line low; when released, MXD1815XR26+T's internal pullup returns the line high - enabling true wired-OR reset arbitration without contention.

What is the minimum supply voltage at which MXD1815XR26+T guarantees valid RESET output logic states?

MXD1815XR26+T guarantees correct RESET/RESET logic states down to VCC = +1.0V, as stated in the Absolute Maximum Ratings and Electrical Characteristics tables. This ensures the output remains predictably high (via internal pullup) or low (when asserted) even during deep brownout conditions - a critical feature for fail-safe operation in battery-powered systems where VCC may sag below normal operating range before shutdown.