General Description

The RT6337 family are high efficiency synchronous

step-down DC-DC converters with pseudo constant

switching frequency 500kHz and deliver up to 9A output

current. The RT6337A/B and RT6337AH/BH operate

from 4.5V to 23V input voltage. The output voltage of

RT6337A/AH is programmed between 0.6V to 5.5V and

RT6337B/BH is fixed to 3.3V output voltage. The input

voltage of RT6337C/CH ranges from 5.2V to 23V and

the output voltage of RT6337C/CH is fixed to 5.1V.

The RT6337 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, RT6337

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, RT6337

provides the best light-load efficiency and improves the

acoustic noise with spread spectrum function.

RT6337 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-23L 3x3

(FC) package.

Features

⚫ Input Voltage Range

 RT6337A/B and RT6337AH/BH: 4.5V to 23V

 RT6337C/CH: 5.2V to 23V

⚫ Output Voltage

 RT6337A/AH: 0.6V to 5.5V

 RT6337B/BH: 3.3V

 RT6337C/CH: 5.1V

⚫ 9A 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

⚫ Internal Power MOSFET Switch 26m (high-side)

and 14m (low-side)

⚫ LDO

 RT6337B/BH: 3.3V/100mA

 RT6337C/CH: 5V/100mA

⚫ Overcurrent Limit

 RT6337A/AH: Adjustable (10A, 12A or 14A)

 RT6337B/BH/C/CH: 13A

⚫ Output Under-/Overvoltage Protection (UVP/OVP)

 RT6337A/B/C: Latched Mode UVP/OVP

 RT6337AH/BH/CH: Hiccup Mode UVP and NonLatched Mode OVP

⚫ Input Undervoltage Lockout (UVLO)

⚫ Over-Temperature Protection (OTP)

 RT6337A/B/C: Latched Mode OTP

 RT6337AH/BH/CH: Non-Latched Mode OTP

⚫ Junction Temperature Range: −40C to 125C

Applications

⚫ Laptop Computers

⚫ Tablet PCs

⚫ Networking Systems

⚫ Servers

⚫ Personal Video Recorders

⚫ Flat Panel Television and Monitors

⚫ Distributed Power Systems