Analog Devices Inc./Maxim Integrated MAX1589EZT250+

Overview

The MAX1589EZT250+ from Maxim Integrated is a low-dropout linear regulator with integrated active-low open-drain RESET output, designed for battery-powered portable electronics. It delivers 500mA continuous output current at 2.5V with ±0.5% initial accuracy, 175mV dropout at full load, and operates from a 1.62V–3.6V input supply - enabling operation down to single-cell Li-ion or Li-poly end-of-discharge voltage. It serves as a primary power rail for microcontroller cores or memory subsystems in space-constrained handheld devices.

For engineers reviewing the MAX1589EZT250+ datasheet, MAX1589EZT250+ pinout, MAX1589EZT250+ application, or MAX1589EZT250+ equivalent, this page provides verified technical context, package-specific pin functionality, real-world application constraints (e.g., thermal limits in SOT23), and validated alternative options for 2.5V LDO + RESET designs requiring low quiescent current and brownout supervision.

Technical Context

The MAX1589EZT250+ uses an internal P-channel MOSFET pass transistor (R_DS(ON) = 0.33Ω) to achieve low dropout and supply-current independence from load or input-output differential. Its error amplifier compares a trimmed bandgap reference against a fixed internal feedback divider to regulate the 2.5V output.

RESET assertion is controlled by a dedicated power-good comparator monitoring V_OUT; it remains asserted for ≥70ms after regulation is achieved and falls immediately if V_OUT drops below 82.5% of nominal. Shutdown logic disconnects the output, pulls OUT to GND via a 1.5kΩ resistor, and reduces supply current to <1µA.

Key Specifications

Pinout & Package

MAX1589EZT250+ is packaged in a RoHS-compliant 6-pin thin SOT23 (1.0mm height, pkg code Z6+1*), with exposed pad omitted - thermal management relies on soldering Pin 2 (GND) to a large PCB copper area.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar LDO regulator with RESET applications.

Compared with TPS79525DBVR and MCP1825-2502E/DB, the MAX1589EZT250+ uniquely combines 175mV dropout, ±0.5% accuracy, and tightly specified 70ms/82.5% RESET behavior in a single 6-pin SOT23 - reducing component count and improving power-rail timing predictability in portable systems.

Availability

MAX1589EZT250+ is available at Aetrix Electronics and suitable for notebook computers, digital still cameras, and cellular telephone power management requiring stable component supply, RoHS compliance, and long-term production continuity.

Supply support for MAX1589EZT250+ 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 portable, industrial, and communications applications.

The MAX1589 family was engineered specifically for ultra-low-input-voltage battery-powered systems needing high-accuracy, low-quiescent-current regulation with integrated power-supervision - targeting PDAs, early smartphones, and compact imaging devices.

FAQ

What is the maximum input voltage the MAX1589EZT250+ can tolerate?

The MAX1589EZT250+ has an absolute maximum input voltage of +4.0V referenced to GND. However, its operational input range is strictly 1.62V to 3.6V per datasheet specifications. Exceeding 3.6V during normal operation risks violating parametric limits and may trigger undervoltage lockout or thermal shutdown. Always limit VIN to ≤3.6V in design, even though the absolute rating allows +4.0V transiently.

Does the MAX1589EZT250+ require external capacitors, and what values are mandatory?

Yes, the MAX1589EZT250+ requires two mandatory external capacitors: a minimum 1µF ceramic capacitor between IN and GND, and a minimum 4.7µF low-ESR ceramic capacitor between OUT and GND. These are not optional - they ensure stability across temperature, load, and input conditions. Using smaller values or high-ESR types (e.g., standard electrolytics) risks oscillation, poor transient response, or failure to regulate under load.

How does the RESET output behave during shutdown or brownout?

During shutdown (SHDN = LOW), the MAX1589EZT250+ actively pulls RESET low. During brownout (VOUT falling below 82.5% of 2.5V = 2.0625V), RESET also asserts low immediately - with no propagation delay. RESET remains low for ≥70ms after VOUT rises above threshold during power-up, and releases only when VOUT sustains regulation. This behavior is guaranteed across -40°C to +85°C.

Can the MAX1589EZT250+ be used in thermally constrained PCB layouts?

Yes, but with strict layout rules: Pin 2 (GND) must be soldered to a ≥1in² copper pour acting as a heatsink. In the 6-pin thin SOT23 package, power dissipation is limited - at 500mA and 1V dropout, power is 0.5W, requiring θ_JA ≤ 110°C/W to stay below +150°C junction limit. Without adequate copper, thermal shutdown will activate. For higher ambient or sustained loads, consider the TDFN variant (MAX1589ETT250+).

Is the MAX1589EZT250+ pin-compatible with other variants in the MAX1589 family?

Yes - all MAX1589 SOT23 variants (e.g., MAX1589EZT180+, MAX1589EZT300+) share identical 6-pin thin SOT23 pinout and footprint. The only differences are preset output voltage and RoHS status (+ suffix). Swapping MAX1589EZT250+ for another SOT23 variant requires no PCB change, but verify that the new output voltage meets downstream IC requirements and that RESET timing remains compatible.