Analog Devices Inc./Maxim Integrated MAX1726EUK33+T

Overview

MAX1726EUK33+T from Maxim Integrated is a fixed-output, ultra-low quiescent current (2µA), low-dropout linear regulator delivering 3.3V at up to 20mA with ±1.5% output voltage accuracy over -40°C to +85°C. It features reverse-battery protection, thermal shutdown, short-circuit foldback limiting, and operates from 2.5V to 12V input-ideal for smoke detector main power and real-time clock backup in battery-constrained systems.

For engineers reviewing the MAX1726EUK33+T datasheet, MAX1726EUK33+T pinout, MAX1726EUK33+T application, or MAX1726EUK33+T equivalent, key selection criteria include guaranteed 20mA output under 2µA IQ, 1µF minimum output capacitance requirement, SOT23-5 package footprint, and factory-trimmed 3.3V output without external resistors.

Technical Context

The MAX1726EUK33+T uses an internal p-channel MOSFET pass transistor with a 1.245V reference error amplifier, enabling ultra-low dropout operation and eliminating base-drive current losses typical of PNP regulators. Its feedback network is fully integrated-no external FB pin-simplifying layout and ensuring stable regulation across temperature and load.

Shutdown is active-low via SHDN pin, reducing supply current to 0.7µA while pulling output to GND. Thermal protection activates at +150°C with 15°C hysteresis, and reverse-battery protection limits VIN < 0V leakage to <10µA when SHDN is driven through a 100kΩ resistor.

Key Specifications

Pinout & Package

MAX1726EUK33+T is housed in a RoHS-compliant 5-pin SOT23 package (package code U5+1, outline 21-0057), with 1.3mm × 2.9mm footprint and 0.95mm height-compatible with standard SOT23 reflow profiles and automated placement.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar low-IQ LDO regulator applications.

Compared with MCP1700T-3302E/TT and TCS2113-3.3VDBVR, the MAX1726EUK33+T uniquely combines 2µA IQ, reverse-battery protection, thermal shutdown, and foldback limiting in a 5-pin SOT23-making it optimal for unattended, safety-critical, or field-deployed battery systems where reliability under fault conditions is non-negotiable.

Availability

MAX1726EUK33+T is available at Aetrix Electronics and suitable for smoke detectors, remote transmitters, and real-time clock backup power requiring stable component supply, long-lifecycle availability, and guaranteed RoHS compliance.

Supply support for MAX1726EUK33+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, mixed-signal, and power-management ICs for industrial, automotive, and computing applications.

The MAX1725/MAX1726 product line delivers ultra-low-IQ LDOs optimized for battery longevity in safety-critical and maintenance-free portable systems-emphasizing reverse protection, thermal resilience, and minimal external components.

FAQ

What is the guaranteed output current capability of the MAX1726EUK33+T?

The MAX1726EUK33+T guarantees 20mA output current across its full operating temperature range (-40°C to +85°C) and input voltage range (2.5V to 12V). This rating is validated per the Electrical Characteristics table and applies under worst-case conditions including dropout and high temperature. The MAX1726EUK33+T is not rated for continuous 100mA or higher loads-exceeding 20mA may cause thermal shutdown or output voltage deviation beyond specification.

Does the MAX1726EUK33+T require an external feedback resistor network?

No, the MAX1726EUK33+T does not require external feedback resistors. It integrates a factory-trimmed voltage divider to deliver a precise 3.3V output. Unlike the adjustable MAX1725 variant-which uses the FB pin and external R1/R2-the MAX1726EUK33+T has no FB pin and relies solely on internal trimming. This eliminates resistor tolerance errors and reduces PCB area, making the MAX1726EUK33+T ideal for compact, cost-sensitive designs.

What protection features are built into the MAX1726EUK33+T?

The MAX1726EUK33+T includes three core protection features: reverse-battery protection (limits VIN < 0V leakage to <10µA), thermal shutdown (activates at +150°C with 15°C hysteresis), and foldback short-circuit limiting (caps output current at ~40mA during hard shorts). These are implemented in silicon-not external circuits-and function independently of external components. All protections are active during normal operation and shutdown, ensuring robustness in unpredictable field environments where the MAX1726EUK33+T is deployed.

Can the MAX1726EUK33+T operate from a single 3.6V Li-ion cell?

Yes, the MAX1726EUK33+T can operate from a single 3.6V Li-ion cell. Its minimum input voltage is 2.5V, and its dropout voltage is 600mV at 20mA (typical), meaning it regulates cleanly down to VIN = 3.9V. As a Li-ion cell discharges from 4.2V to 3.0V, the MAX1726EUK33+T maintains 3.3V output until the cell reaches ~3.9V-covering most of the usable discharge curve. Below that, output follows input (dropout mode), but the MAX1726EUK33+T remains functional and protected.

What is the recommended output capacitor for stable operation of the MAX1726EUK33+T?

The MAX1726EUK33+T is specified for stable operation with a minimum 1µF ceramic capacitor (X5R or X7R dielectric) placed directly between OUT and GND. This value ensures phase margin >45° across -40°C to +85°C and load currents up to 20mA. Larger values (e.g., 2.2µF–10µF) improve transient response and PSRR but are not required. Aluminum or tantalum capacitors are not recommended due to ESR and aging effects that may compromise stability. The 1µF requirement directly enables simplified BOMs in space-constrained applications using the MAX1726EUK33+T.