Selecting_LDO_Linear_Regulators for Cellphone_DesignsPORTABLE POWER POWER-SUPPLY CIRCUITSApplication Note 898: Dec 26, 2001Selecting LDO Linear Regulators for Cellphone DesignsLow-dropout LDO linear regulators are used to power many sections of a typical cellular handset. However, these baseband, RF, and audio sections have different requirements that influence which LDO is most appropriate. After discussion of the specific requirements, different LDOs are recommended. Also, some LDO design techniques are briefly discussed to demonstrate how an LDO may be optimized for a specific level of performance. Cellular phone designs require linear regulators with low-dropout, low-noise, high PSRR, low quiescent current (Iq), and low-cost. They need to deliver a stable output and use small-value output capacitors. Ideally, one device would have a……