®
RT6248B
18V, 8A, 500kHz ACOT
TM
Synchronous Step-Down Converter
General Description
The RT6248B is a simple, easy-to-use, 8A synchronous
step-down DC-DC converter with an input supply voltage
range of 4.5V to 18V. The device build-in an accurate 0.6V
reference voltage and integrates low R
DS(ON)
power
MOSFETs to achieve high efficiency in a UQFN-12HL 3x3
package. The RT6248B adopts Advanced Constant On-
Time (ACOT
TM
) control architecture to provide an ultrafast
transient response with few external components and to
operate in nearly constant switching frequency over the
line, load, and output voltage range. The RT6248B operates
in Forced PWM that helps meet tight voltage regulation
accuracy requirements. The RT6248B senses both FETs
current for a robust over-current protection. It features
cycle-by-cycle current limit protection and prevent the
device from the catastrophic damage in output short circuit,
over current or inductor saturation. A built-in soft-start
function prevents inrush current during start-up. The device
also includes input under-voltage lockout, output under-
voltage protection, over-voltage protection, and over-
temperature protection (thermal shutdown) to provide safe
and smooth operation in all operating conditions. The
RT6248B is offered in a UQFN-12HL 3x3 (FC) package.
Features
Ω
Ω
8A Converter With Built-in 24mΩ/12mΩ Low R
DS(ON)
Power FETs
Input Supply Voltage Range : 4.5V to 18V
Output Voltage Range : 0.6V to 6V
Advanced Constant On-Time (ACOT
TM
) Control
�½
Ultrafast
�½
Transient Response
No Needs for External Compensations
�½
Optimized for Low-ESR Ceramic Output Capacitors
0.6V
±
1% High-Accuracy Feedback Reference
Voltage
Fixed Switching Frequency : 500kHz
Built-In Internally Fixed Soft-Start (Typ. 0.4ms)
Input Under-Voltage Lockout (UVLO)
Output Under-Voltage Protection (UVP) with Hiccup
Mode
Output Over-Voltage Protection (OVP) with Auto-
Recovery Mode
Available in UQFN-12HL 3x3 (FC) Package
Applications
Industrial and Commercial Low Power Systems
Computer Peripherals
LCD Monitors and TVs
Green Electronics/Appliances
Point of Load Regulation for High-Performance DSPs,
FPGAs, and ASICs
Networking Communication
Simplified Application Circuit
RT6248B
PGOOD
R
BOOT
BOOT
V
IN
C
IN
LX
V
CC
C
VCC
VCC
C
FF
(Optional)
R
FF
(Optional)
ILMT
R
EN
V
EN
EN
AGND
PGND
BYP
C
BYP
R
BYP
(Optional)
V
BYP
FB
R2
R1
C
OUT
VIN
C
BOOT
L
V
OUT
V
PGOOD
V
ILMT
Copyright
©
2018 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS6248B-01 May 2018
www.richtek.com
1
RICHTEK [ RICHTEK TECHNOLOGY CORPORATION ]
