LDO regulators

An LDO (low-dropout) is a linear voltage regulator designed to operate with a very low input-to-output voltage differential (dropout voltage). It aims to minimize the power dissipated as heat on the device and increase conversion efficiency.

ST's LDO regulators offer an optimal combination of:

• low dropout voltage
• low quiescent current (low IQ)
• fast transient response
• low noise
• and good ripple rejection

Product overview

Ultra-low dropout

The dropout voltage is the defined minimum difference between the input voltage and the desired output voltage at a specified output current. An ultra-low-dropout voltage extends the lifetime of battery-operated devices, as it allows the LDO to maintain a high current output even when the battery voltage is reduced as the battery is discharged. Furthermore, it reduces power dissipation.

Low quiescent current

Quiescent current is the current used to power an LDO’s internal circuitry. LDOs with low quiescent current are essential for maintaining efficient operation and prolonging battery life, and are a natural choice for applications with extended standby times.

High PSRR/Low noise

PSRR is a measure of the LDO’s ability to endure a changing input voltage without letting it affect the output, while low noise LDOs are designed to minimize the intrinsic noise. Maintaining the expected output voltage with high precision and low noise is vital when powering sensitive devices or when the supply voltage is derived from a noisy source.