FAN2558SX

Voltage Regulators - Linear, Low Drop Out (LDO) Regulators Overview

The FAN2558SX is a discontinued adjustable output low dropout regulator manufactured by onsemi. It provides an output current of 180mA with a ground current of 100µA. The device operates within an input voltage range of 2.7V to 5.5V and supports an adjustable output voltage from 1V to near the input voltage. It features a TTL-level compatible enable pin, an open-drain power good indicator, and active output discharge. The component is housed in a SuperSOT-6 package and includes thermal shutdown and current limit protection.

Voltage Regulators - Linear, Low Drop Out (LDO) Regulators Feature Summary

• Adjustable output voltage configuration utilizing external resistor dividers connected to the ADJ pin
• Integrated power good diagnostic function providing an open-drain status signal for output regulation verification
• TTL-compatible enable control allowing for fast shutdown and ultra-low quiescent current consumption
• Built-in thermal shutdown and current limiting circuits to protect against overheating and short circuit conditions

Voltage Regulators - Linear, Low Drop Out (LDO) Regulators Applications

• Processor power-up sequencing systems
• Cell phones and PDAs
• Portable electronic equipment
• PCMCIA Vcc and Vpp regulation

Voltage Regulators - Linear, Low Drop Out (LDO) Regulators Procurement Notes

Verify that the FAN2558SX is marked as discontinued and not recommended for new designs. Confirm availability through onsemi representatives for potential last-time buys or legacy support. Ensure replacement components are evaluated for compatibility with existing PCB footprints and electrical requirements before integration into any system.

Voltage Regulators - Linear, Low Drop Out (LDO) Regulators Selection Notes

Select this component only for legacy designs requiring an adjustable LDO with a SuperSOT-6 footprint. Evaluate alternative packages such as MLP-6 or SOT-23-5 if new designs are permitted. Verify that the required output voltage range falls between 1V and the input supply voltage. Confirm that the 180mA load current and 100µA ground current meet the specific power budget constraints of the application.

Voltage Regulators - Linear, Low Drop Out (LDO) Regulators Part Context

The FAN2558SX belongs to the FAN2558/FAN2559 family of low voltage CMOS LDOs produced by onsemi following the Fairchild Semiconductor integration. This family offers fixed and adjustable output options with high ripple rejection and low noise characteristics. The SX suffix specifically denotes the adjustable version packaged in a 6-Lead SOT-23 format, distinct from the fixed voltage variants and other package types available within the same product line.

Voltage Regulators - Linear, Low Drop Out (LDO) Regulators Replacement Considerations

FAN2558MPX (MLP-6 Package)

Voltage Regulators - Linear, Low Drop Out (LDO) Regulators FAQ

How is the output voltage determined for the FAN2558SX?

The output voltage is set by connecting an external resistor divider between the VOUT and GND pins, with the center tap connected to the ADJ pin. The internal feedback voltage reference is approximately 0.59V.

What is the function of the Power Good (PG) pin?

The PG pin is an open-drain output that indicates when the regulated output voltage has stabilized within 5% of its nominal value. It goes LOW during fault conditions such as input dropout, overheating, or overloading.

Does the FAN2558SX include a bypass pin for noise reduction?

No, the FAN2558SX does not have a dedicated bypass pin. Noise reduction via a bypass capacitor is a feature available only in the FAN2559 fixed-output variant.