High PSRR, Low Dropout, 400mA Adjustable LDO Regulator


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The RT9043 is a high-performance, 400mA LDO regulator, offering high PSRR and low dropout. The quiescent current is as low as 35μA, further prolonging the battery life. The RT9043 also works with low-ESR ceramic capacitors, reducing the amount of board space necessary for power applications, critical in handheld wireless devices.

The RT9043 consumes typical 0.7μA in shutdown mode. The other features include low dropout voltage, high output accuracy, current limit protection, and enable/shutdown control. The RT9043 is available in the SOT-23-5 package.


  • Mega SIM Card
  • CDMA/GSM Cellular Handsets
  • Portable Information Appliances
  • Laptop, Palmtops, Notebook Computers
  • Hand-Held Instruments
  • Mini PCI & PCI-Express Cards
  • PCMCIA & New Cards
  • Notebooks
Key Spec.
Status Active
Vin (min) (V) 2.2
Vin (max) (V) 5.5
Vout (min) (V) 1.2
Vout (max) (V) 5
Output Adj. Method Resistor
Accuracy (+/- %) 1
Iout (max) (mA) 400
Iq (typ) (uA) 35
Vdropout @ rated current (typ) (mV) 230 @ 0.4A
Cout Type Ceramic
Features Enable Input;Extra Low Noise;Low Dropout;OCP;Stable with Ceramic Capacitor
Package Type SOT-25
  • Adjustable Output Voltage
  • Enable/Shutdown Control
  • Wide Operating Voltage Range : 2.2V to 5.5V
  • Low Dropout : 230mV at 400mA
  • Low-Noise for RF Application
  • Ultra-Fast Response in Line/Load Transient
  • Current Limit Protection
  • High Power Supply Rejection Ratio
  • Output Only 1μF Capacitor Required for Stability
  • RoHS Compliant and Halogen Free
TitleLast UpdateShareDownload
High PSRR, Low Dropout, 400mA Adjustable LDO Regulator2009/02/05
Title Last Update ShareDownload
High PSRR, Low Dropout, 400mA Adjustable LDO Regulator 2015/05/19
Technical Documents
TitleLast UpdateShareDownload
Richtek Selection Guide [Oct., 2020]2020/12/30
Additional Documents
Title Last Update ShareDownload
Power Management Introduction and Selection Guide 2020/12/07
Part NumberPackage TypePackage Qty.Free SampleBuy From Authorized Distributor
RT9043GBSOT-253000 Not available Buy from Distributor