300/600mA, Ultra-Fast Transient Response LDO Regulator


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The RT9166/A series are CMOS low dropout regulators optimized for ultra-fast transient response. The devices are capable of supplying 300mA or 600mA of output current with a dropout voltage of 230mV or 580mV respectively.

The RT9166/A series are is optimized for CD/DVD-ROM, CD/RW or wireless communication supply applications. The RT9166/A regulators are stable with output capacitors as low as 1μF. The other features include ultra low dropout voltage, high output accuracy, current limiting protection, and high ripple rejection ratio.

The devices are available in fixed output voltages range of 1.2V to 4.5V with 0.1V per step. The RT9166/A regulators are available in 3-lead SOT-23 (RT9166 only), SOT-89,
SOT-223, TO-92 and TO-252 packages.


  • Wireless LAN Card/Keyboard/Mouse
  • Battery-Powered Equipment
  • XDSL Router
  • PCMCIA Card
Key Spec.
RT9166 RT9166A
Status Active Active
Vin (min) (V) 2.8 2.8
Vin (max) (V) 5.5 5.5
Vout (min) (V) 1.2 1.2
Vout (max) (V) 4.5 4.5
Output Adj. Method Fixed Fixed
Accuracy (+/- %) 3 3
Iout (max) (mA) 300 600
Iq (typ) (uA) 220 220
Vdropout @ rated current (typ) (mV) 230 @ 0.3A;580 @ 0.6A 230 @ 0.3A;580 @ 0.6A
Cout Type Ceramic Ceramic
Features OCP;Stable with Ceramic Capacitor OCP;Stable with Ceramic Capacitor
Package Type SOT-223;SOT-23;SOT-89 SOT-223;SOT-23;SOT-89
  • Low Quiescent Current (Typically 220mA)
  • Guaranteed 300/600mA Output Current
  • Low Dropout Voltage : 230/580mV at 300/600mA
  • Wide Operating Voltage Ranges : 3V to 5.5V
  • Ultra-Fast Transient Response
  • Tight Load and Line Regulation
  • Current Limiting Protection
  • Thermal Shutdown Protection
  • Only Low-ESR Ceramic Capacitor Required for Stability
  • Custom Voltage Available
  • RoHS Compliant and 100% Lead (Pb)-Free
TitleLast UpdateShareDownload
300/600mA, Ultra-Fast Transient Response LDO Regulator2007/01/08
Title Last Update ShareDownload
300/600mA, Ultra-Fast Transient Response LDO Regulator 2015/05/19
Technical Documents
TitleLast UpdateShareDownload
Richtek Selection Guide [Oct., 2020]2020/12/30
Part NumberPackage TypePackage Qty.Free SampleBuy From Authorized Distributor
RT9166-12GVLSOT-233000 Request Buy from Distributor
RT9166-18GVLSOT-233000 Not available Buy from Distributor
RT9166-28GVLSOT-233000 Not available Buy from Distributor
RT9166-33GVLSOT-233000 Not available Buy from Distributor
RT9166A-12GXLSOT-891000 Not available Buy from Distributor