If you want to step down the supply voltage, select either DCDC converter or LDO regulator?

The step-down DCDC converter and LDO regulator both have a voltage-down function.

DCDC converter and LDO regulator are compared below.

  LDO DCDC converter
Number of peripheral parts
 ✔✔✔ ✔
Stand-by power consumption
 ✔✔✔ ✔
Noise characteristics
 ✔✔✔ ✔
Power efficiency
 ✔ ✔✔✔✔

✔:Average    ✔✔:Good、  ✔✔✔:Very Good     ✔✔✔✔:Excellent

DCDC converters are often selected in the following situations:

  • Emphasize power conversion efficiency
  • Don't worry about noise.

In the following cases, LDO are often selected.

  • I want to reduce the number of components required to step down the power supply voltage
  • Reducing standby power consumption
  • Be important in noise characteristics

The main advantages of LDO are described below.

Advantage of LDO 1: Simple circuitry with fewer components

Advantage of LDO 1: Simple circuitry with fewer components

LDO has a small circuitry and can be powered by external components. Therefore, it is cheaper and consumes less current. In addition, since the control is also simple, voltage can be output without fine adjustment.

Benefits of LDO 2: Low-noise power output

 Benefits of LDO 2: Low-noise power output

Since LDO controls the voltage by the movement of the variable resistor, the voltage can be outputted with relatively low noises.
DCDC is switched and smoothed by a LC filter, so it can be used in a steady state.
The power is waving. (voltage ripple)

Related Links

The following documents also contain related information.

Product Lists

Application Notes

Product page Low-Dropout Regulators (LDO Regulators)
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e-Learning Basics of Low-Dropout (LDO) Regulators
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