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The RT6321 is high efficiency synchronous step-down DC-DC converters with pseudo constant switching frequency 500kHz and deliver up to 12A output current. The RT6321 operates from 4.5V to 23V input voltage. The output voltage of RT6321 is programmed between 0.6V to 5.5V. The RT6321 supports low power mode (LPM) to dynamically change output voltage between target voltage and zero voltage.

The RT6321 adopts Advanced Constant On-Time (ACOT®) control architecture that provides ultra-fast transient response and further reduces the external component count. In steady states, the ACOT® operates at nearly constant switching frequency over line, load and output voltage ranges and makes the EMI filter design easier.

By setting the voltage of the EN/MODE pin, RT6321 operates either in diode emulation mode (DEM) or ultrasonic mode (USM) at light load. The USM maintains operation frequency above 25kHz, which eliminates the acoustic noise. In the DEM, RT6321 provides the best light-load efficiency and improves the acoustic noise with spread spectrum function.

RT6321 provides PGOOD indicator for easy system sequence control. Full protection features are also integrated in the device, including the cycle-by-cycle current limit, OVP, UVP, input UVLO and OTP.

All above functions are integrated in a UQFN-26L 4x3 (FC) package.

Applications

  • Laptop Computers
  • Tablet PCs
  • Networking Systems
  • Servers
  • Personal Video Recorders
  • Flat Panel Television and Monitors
  • Distributed Power Systems
Key Spec.
RT6321A
Status Active
Vin (min) (V) 4.5
Vin (max) (V) 23
Number of Outputs 1
Vout (min) (V) 0.6
Vout (max) (V) 5.5
Output Adj. Method Resistor
Iout (max) (A) 12
Current Limit (typ) (A) 14;16;18
Freq (typ) (kHz) 500
Ext Sync No
Ron_HS (typ) (mOhm) 17
Ron_LS (typ) (mOhm) 7.5
Iq (typ) (mA) 0.085
Features ACOT Control;Adjustable Current Limit;Cycle-by-Cycle Current Limit;Enable Input;Fast Transient Response;Internal Compensation;OCP;OTP;OVP;PSM;Power Good;Stable with Ceramic Capacitor;UVP;Ultrasonic Mode Control
Package Type UQFN4x3-26(FC)
Features
  • Input Voltage Range: 4.5V to 23V
  • Output Voltage: 0.6V to 5.5V
  • 12A Continuous Output Current
  • Stable with POSCAP and MLCC Capacitor
  • Fast Transient Response
  • Diode Emulation Mode (DEM) for Power Saving
  • Ultrasonic Mode (USM) for Avoiding Acoustic Noise
  • Pseudo Constant Switching Frequency 500kHz in CCM
  • Low-Power Mode (LPM)
  • Internal Power MOSFET Switch 17mΩ (high-side) and 7.5mΩ (low-side)
  • Overcurrent Limit: Adjustable (14A, 16A or 18A)
  • Output Under-/Overvoltage Protection (UVP/OVP)
    ► RT6321A: Latched Mode UVP/OVP
    ► RT6321AH: Hiccup Mode UVP and Non-Latched Mode OVP
  • Input Undervoltage-Lockout (UVLO)
  • Over-Temperature Protection (OTP)
    ► RT6321A: Latched Mode OTP
    ► RT6321AH: Non-Latched Mode OTP
  • Junction Temperature Range: -40°C to 125°C
Part NumberPackage TypePackage Qty.Free SampleDistributorStockBuy From Authorized Distributor
RT6321AN-AUQFN4x3-26(FC)1,500 Request Digikey 1,500 Buy
Mouser 0 Lead-Time: 14 weeks
Evaluation Board
Part NumberDistributorStockBuy From Authorized Distributor
EVB_RT6321AN-A Digikey 5 Buy
Mouser 0 Lead-Time: 14 weeks
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