1A, Ultra-Low Dropout, Ultra-Fast CMOS LDO Regulator


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The RT9187 is a high-performance, 1A LDO regulator, offering extremely high PSRR and ultra-low dropout. Ideal for portable RF and wireless applications with demanding performance and space requirements.
A noise reduction pin is also available for further reduction of output noise. Regulator ground current increases only slightly in dropout, further prolonging the battery life. The RT9187 also works with low-ESR ceramic capacitors, reducing the amount of board space necessary for power applications, critical in hand-held wireless devices.
The RT9187 consumes less than 0.1μA in shutdown mode and has fast turn-on time less than 40μs. The other features include ultra-low dropout voltage, high output accuracy, current limiting protection, and high ripple rejection ratio. Available in the VDFN-8L 3x3 and SOP-8 (Exposed Pad) package.


  • CDMA/GSM Cellular Handsets
  • Battery-Powered Equipment
  • Laptop, Palmtops, Notebook Computers
  • Hand-Held Instruments
  • Mini PCI & PCI-Express Cards
  • PCMCIA & New Cards
  • Portable Information Appliances
Key Spec.
Status Active
Vin (min) (V) 2.5
Vin (max) (V) 5.5
Vout (min) (V) 0.8
Vout (max) (V) 4.5
Output Adj. Method Fixed;Resistor
Accuracy (+/- %) 1.5
Iout (max) (mA) 1000
Iq (typ) (uA) 380
Vdropout @ rated current (typ) (mV) 240 @ 1A
Bias Rail Yes
Cout Type Ceramic
Features Enable Input;Extra Low Noise;Low Dropout;OCP;Stable with Ceramic Capacitor
Package Type VDFN3x3-8;PSOP-8
  • Ultra-Low-Noise for RF Application
  • Ultra-Fast Response in Line/Load Transient
  • Quick Start-Up (Typically 40μs)
  • < 0.1μA Standby Current When Shutdown
  • Low Dropout : 240mV at 1A
  • Wide Operating Voltage Ranges : 2.5V to 5.5V
  • TTL-Logic-Controlled Shutdown Input
  • Current Limiting Protection
  • Thermal Shutdown Protection
  • Only 2.2μF Output Capacitor Required for Stability
  • High Power Supply Rejection Ratio
  • RoHS Compliant and 100% Lead (Pb)-Free
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1A, Ultra-Low Dropout, Ultra-Fast CMOS LDO Regulator2005/05/18
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1A, Ultra-Low Dropout, Ultra-Fast CMOS LDO Regulator 2015/05/19
Technical Documents
TitleLast UpdateShareDownload
Richtek Selection Guide [Oct., 2020]2020/12/30
TitleLast UpdateShareViews
LDO Dropout Voltage Explained2015/03/18 169
Additional Documents
Title Last Update ShareDownload
Power Management Introduction and Selection Guide 2020/12/07
Part NumberPackage TypePackage Qty.Free SampleBuy From Authorized Distributor
RT9187GQVVDFN3x3-81500 Not available Buy from Distributor
RT9187GSPPSOP-82500 Not available Buy from Distributor