onsemi FAN2558MP15X

Overview

FAN2558MP15X from onsemi is a fixed-output 1.8V, 180mA low-dropout linear regulator (LDO) in a 2×2mm 6-lead MLP package, featuring power-good indication, 1% output voltage accuracy, and ultra-low 100µA ground current - deployed in portable electronics for stable core voltage regulation under dynamic load conditions.

For engineers reviewing the FAN2558MP15X datasheet, pinout, applications, or equivalent options, key selection criteria include dropout voltage at 180mA (400mV), thermal shutdown threshold (150°C), PSRR of 50dB (≤100kHz), and compatibility with 0–300mΩ ESR output capacitors without external compensation.

Technical Context

The FAN2558MP15X uses BiCMOS process technology with a P-channel MOSFET pass element and trimmed bandgap reference to achieve 1% initial output accuracy and excellent line/load regulation (±0.3%/V and ±4%). Its control loop is optimized for stability with ceramic, tantalum, or electrolytic output capacitors ranging from 1µF to ≥4.7µF and ESR up to 300mΩ.

It integrates fast-enable logic (30–300µs response), open-drain power-good monitoring with 89–97% VOUT threshold hysteresis, active output discharge via internal 100Ω pull-down, and dual protection: current limit (260–500mA) and thermal shutdown with 10°C hysteresis. The 6-lead MLP package provides θJC = 75°C/W for improved thermal performance over SOT-23 variants.

Key Specifications

Pinout & Package

Package: 2×2mm, 0.5mm pitch, 6-lead MLP (micro lead frame) - thermally enhanced surface-mount package with exposed thermal pad for PCB heat dissipation (θJA ≈ 130–180°C/W depending on copper area).

Key Features

Applications

Equivalent & Alternatives

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

Compared with FAN2558MP15X, MCP1826T-1802E/DB offers higher current headroom but sacrifices system-level fault detection and output discharge control; NCP114AMX180TBG improves efficiency and dropout but lacks the 125°C junction rating and bypass-capacitor noise suppression critical for precision analog subsystems.

Availability

FAN2558MP15X is available at Aetrix Electronics and suitable for smartphone processor rails, PCMCIA interface regulation, portable medical sensor hubs, and wearable MCU supplies requiring stable component supply with full lifecycle support and traceable sourcing.

Supply support for FAN2558MP15X 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

onsemi (formerly Fairchild Semiconductor) is a global semiconductor supplier specializing in energy-efficient power management, analog, sensing, and connectivity solutions for automotive, industrial, cloud, and consumer markets.

The FAN2558MP15X belongs to onsemi's low-voltage CMOS LDO family designed specifically for battery-powered portable electronics requiring high PSRR, low noise, fast enable, and robust thermal/current protection in ultra-compact packages.

FAQ

What is the maximum input voltage rating for the FAN2558MP15X?

The FAN2558MP15X has an absolute maximum input voltage (VIN to GND) of 6V. However, the recommended operating range is 2.7V to 5.5V for 1.8V output. Exceeding 5.5V risks permanent damage even if within the 6V absolute maximum, due to internal gate oxide stress and thermal limits. Always observe the recommended VIN range in design.

Does the FAN2558MP15X require an external bypass capacitor?

Yes - the FAN2558MP15X includes a BYP pin that accepts a 0–47nF capacitor to ground for ultra-low-noise operation. While the device functions without it, omitting the bypass capacitor increases output noise to ~30µV_RMS; adding a 10nF ceramic capacitor reduces broadband noise significantly, especially critical for ADC reference or RF-sensitive applications using the FAN2558MP15X.

Is the FAN2558MP15X pin-compatible with other members of the FAN2558 family?

No - the FAN2558MP15X uses a 6-lead MLP package, while FAN2558S18X uses a 5-lead SOT-23. Pin assignments differ: MLP places BYP on pin 5 and GND on pin 2, whereas SOT-23 has no BYP pin and assigns GND to pin 2 and VOUT to pin 5. PCB layout and footprint are not interchangeable between these variants of the FAN2558 family.

What is the purpose of the PG (Power Good) pin on the FAN2558MP15X?

The PG pin on the FAN2558MP15X is an open-drain output that signals when the regulated 1.8V output is within specification: it pulls LOW when VOUT falls below 89% (1.602V) and goes HIGH (via external pull-up) when VOUT rises above 97% (1.746V). This enables precise power sequencing and fault detection in systems using the FAN2558MP15X, such as mobile SoC boot controllers.

Can the FAN2558MP15X be used with aluminum electrolytic output capacitors?

Yes - the FAN2558MP15X is explicitly designed to remain stable with output capacitors having ESR values from 0mΩ up to 300mΩ, including aluminum electrolytic types. However, ceramic capacitors are preferred for lower ESR, smaller size, and better transient response. When using aluminum electrolytics, ensure minimum 1µF capacitance and verify ESR stays within the 0–300mΩ window per the FAN2558MP15X datasheet.