Low Dropout (LDO) Linear Regulators

Low dropout (LDO) linear voltage regulators are designed to operate with a very low input-to-output voltage differential (dropout voltage).
They minimize the power dissipated as heat on a device and increase conversion efficiency.

Linear voltage regulators offer a cost-effective approach to delivering stable and regulated output voltages, with design simplicity and few external components. LDO regulators provide the best cost-performance tradeoff in applications where the output current is less than few amps and the output voltage is close to that of the input.

Low Dropout (LDO) Linear Regulators, low quiescent current, Low noise High PSRR, linear voltage regulators Tiny Package Low Dropout Low Noise / High PSRR Low Quiescent Current

ST ultralow dropout regulators are ideal for battery-powered consumer and industrial applications, as well as portable healthcare devices, thanks to the following benefits:

Signal fidelity is maintained over a wide range of input voltages and output currents along the entire signal path, thanks to the high PSRR (power supply rejection rate) and low noise.

Differences between LDO regulators and switching converters

Compared to DC-DC switching converters, LDO regulators don’t generate ripple, and therefore offer a very clean supply voltage. They also reduce design effort thanks to the minimal number of external passive components needed.

Product types

High PSRR LDO regulators
This series strongly mitigates (up to 95 dB) dynamic input voltage variation over a wide frequency range.
Low Iq LDO regulators
The very limited internal consumption (below 1 µA) of this series helps extend battery life in portable applications.
Ultralow dropout LDO regulators
This series offers a minimal difference between the input and output voltages, which reduces internal dissipation and improves efficiency.

Discover our portfolio

LDO product portfolio, low quiescent current (low IQ), fast transient response, low noise


ST LDO regulators offer the following combination of benefits:

  • low dropout voltage
  • low quiescent current (low IQ)
  • fast transient response
  • low noise
  • good ripple rejection
ldo regulators low dropout
STLQ020, our LDO drops the mic
with fast response and 300 nA of quiescent current

LDL40, LDH40 and LDQ40: power management solutions for Automotive applications

AEC-Q100 grade 1 qualified and available in DFN 2x2 6L package with wettable flank, the LDH40, LDL40 and LDQ40 are the right choice for engineers and designers looking to optimize their power management systems in applications such as infotainment, EV powertrain, instrument clusters, and ADAS.

The LDQ40 can provide an output current up to 250 mA with ± 1.5 % accuracy in all the working conditions, while both LDH40 and LDL40 can provide up to 200 mA with ± 2.5 % accuracy.

They feature internal current limit, short-circuit protection (LDQ40 only), thermal shutdown, and output active discharge function for added safety and protection.

Power-good for fixed versions, and logic-controlled electronic shutdown, allow the devices to offer precise control and reliable operations.

A low ground current of just 2 μA at no load, makes the voltage regulators also ideal for use in always-on battery-connected applications, ensuring maximum efficiency and minimal power consumption.

A flexible power management solution to design your project quickly and efficiently

The STEVAL-QUADV01 evaluation board is a versatile tool based on different step-down regulators: the L6981, L7983, ST1PS03, and the ST730 LDO. These regulators offer a range of features and capabilities that make the board suitable for a wide range of applications.

The board offers four distinct approaches for generating a 5 V output voltage, which can be conveniently adjusted to alternative values by modifying the resistors in the feedback networks' resistive dividers.

To simulate and configure the L6981, L7983, and ST1PS03 step-down converters, you can use the eDesignSuite and eDSim software tools. It enables you to optimize the performance of the regulators meeting the specific needs of your application, before verifying the results on the evaluation board.

Ultra-tiny low-dropout regulator in breakthrough bumpless chip-scale package

The LDBL20 is a powerful 200 mA LDO in a tiny 0.47 x 0.47 mm innovative ST STAMP™ chip-scale package. The input voltage can range from 1.5 to 5.5 V, with 200 mV typical dropout. Rejection (PSRR) of 80 dB at 100 Hz and 50 dB at 100 kHz simplifies filtering over a wide frequency range to provide a stable rail for low-power circuitry in battery-operated applications. Quiescent current of 20 µA no-load, 100 µA full-load, and 0.3 µA in standby help maximize efficiency under all operating conditions. 
More from Low Dropout (LDO) Linear Regulators portfolio