Power Management IC Selection Guide

  2. Selection Guide

Overview

Richtek has a large portfolio of LDOs (linear regulator) and DC/DC converters/controllers. The below table below shows a quick view on general selection criteria for LDO and DC/DC switching converter products.

The first step of design considerations is the input to output voltage difference (VIN-VOUT).

Specific application requirements like efficiency, thermal limits, noise, complexity and cost need to be taken into consideration in order to select an optimal power solution.

The table below provides a quick view on the basic criteria for selecting LDO, Buck , Boost or Buck-boost

Table 1. Power Management IC Selection Criteria
VIN, VOUT Condition Additional Condition Suitable Topology Advantage Disadvantage
VIN > VOUT
  • Low current
  • Low VIN VOUT ratio
  • Noise sensitive application
 LDO
  • Simple
  • Cheap
  • Low noise
  • Fast
  • Low efficiency
  • Thermal limit
  • High current
  • High VIN VOUT ratio
 Buck
  • High efficiency
  • Flexible
  • Switch noise
VIN < VOUT Boost
  • Good efficiency
  • Switch noise
VIN < > VOUT
  • When VIN can be smaller or larger than VOUT
    • i.e.: Battery input
 Buck-boost
  • Good efficiency
  • Switch noise