onsemi FAN2558MPX

Overview

FAN2558MPX from ON Semiconductor is a fixed-output, 180mA low-dropout linear regulator in a 2×2mm 6-lead MLP package, delivering 1.0V output with ±1% accuracy, 100µA ground current, and open-drain Power Good (PG) indicator. It supports processor power-up sequencing and portable electronics requiring stable low-noise bias under 2.7–5.5V input.

For engineers reviewing the FAN2558MPX datasheet, pinout, applications, or equivalent options, key selection criteria include its 1.0V fixed output, 400mV dropout at 180mA, 50dB PSRR (≤100kHz), active output discharge, and TTL-compatible enable with 30–300µs response time - all validated for PDAs, PCMCIA, and battery-powered embedded systems.

Technical Context

The FAN2558MPX employs BiCMOS technology with a P-channel MOSFET pass element and trimmed bandgap reference to achieve 1% initial output accuracy and excellent line/load regulation. Its control loop is optimized for stability with 0–300mΩ ESR output capacitors, eliminating need for high-ESR tantalum types.

It integrates thermal shutdown (150°C trip, 10°C hysteresis), current limit (260–500mA), and fast enable logic with <1µA shutdown current. The PG pin asserts low when VOUT falls below 89% of nominal, with 1–5ms delay, supporting reliable system power monitoring in compact layouts.

Key Specifications

Pinout & Package

Package: 2×2mm 6-lead MLP (micro leadframe package), thermally enhanced for surface-mount assembly with low θJC = 75°C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with NCP1117ST10T3G and MCP1700T-1002E/TT, the FAN2558MPX uniquely combines 1.0V ±1% accuracy, integrated PG signaling, 2×2mm MLP packaging, and 30–300µs enable response - making it optimal for space-constrained, sequenced, and noise-sensitive 1V applications where diagnostics and timing control are essential.

Availability

FAN2558MPX is available at Aetrix Electronics and suitable for processor power sequencing, portable medical sensors, PCMCIA interface regulation, and handheld electronics requiring stable component supply with full lifecycle support.

Supply support for FAN2558MPX 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

ON Semiconductor (formerly Fairchild Semiconductor) is a global supplier of energy-efficient semiconductor solutions, specializing in power management, analog, and sensing technologies for automotive, industrial, and portable markets.

The FAN2558MPX belongs to ON Semiconductor's low-voltage CMOS LDO family, designed specifically for battery-powered portable electronics demanding high accuracy, low noise, small footprint, and integrated power-good monitoring.

FAQ

What is the output voltage tolerance of the FAN2558MPX?

The FAN2558MPX delivers a fixed 1.0V output with guaranteed ±1% accuracy across temperature (-40°C to +85°C) and load (100µA to 180mA), verified per datasheet electrical characteristics. This tight tolerance ensures reliable operation of 1V-core digital logic without external trimming or calibration. The FAN2558MPX achieves this using an onboard trimmed bandgap reference and BiCMOS error amplifier architecture.

Does the FAN2558MPX include a Power Good (PG) output, and how does it function?

Yes, the FAN2558MPX features an open-drain Power Good (PG) output that asserts low when VOUT drops below 89% of nominal (i.e., <0.89V). It provides a 1–5ms delay after VOUT stabilizes before asserting high, ensuring clean reset signaling. A 47kΩ external pull-up resistor is recommended. This PG functionality is integral to the FAN2558MPX design and enables safe processor boot sequencing and fault detection in portable systems.

What package type is used for the FAN2558MPX, and what are its thermal advantages?

The FAN2558MPX uses a 2×2mm 6-lead MLP (micro leadframe package), offering superior thermal performance versus standard SOT-23. Its junction-to-case thermal resistance (θJC) is 75°C/W, enabling efficient heat transfer to the PCB copper. This allows sustained 180mA operation at ambient temperatures up to +85°C without derating - a key advantage of the FAN2558MPX in dense, thermally constrained portable layouts.

Can the FAN2558MPX operate with ceramic output capacitors, and what is the minimum value required?

Yes, the FAN2558MPX is fully stable with ceramic output capacitors as low as 1µF and ESR from 0mΩ to 300mΩ - confirmed in the datasheet's stability section. Unlike older LDOs, it does not require high-ESR tantalum types. This simplifies design, reduces cost, and improves reliability. The FAN2558MPX's control loop is specifically optimized for low-ESR ceramics, making 1µF X5R/X7R MLCCs the recommended choice.

Is the FAN2558MPX suitable for new designs, and what is its lifecycle status?

The FAN2558MPX is marked "DISCONTINUED - NOT RECOMMENDED FOR NEW DESIGN" in the official ON Semiconductor documentation. While still available through Aetrix Electronics for legacy support and existing production, engineers should consult ON Semiconductor representatives for approved replacements such as the NCP1117 or newer AP73xx series. Lifecycle continuity planning for the FAN2558MPX is actively managed by Aetrix Electronics.