®
RT6278A/B
23V, 8A, 500kHz ACOT
TM
Synchronous Step-Down Converter
General Description
The RT6278A/B is a simple, easy-to-use, 8A synchronous
step-down DC-DC converter with an input supply voltage
range of 4.5V to 23V. 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 RT6278A/B 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 RT6278A operates
in automatic PSM that maintains high efficiency during
light load operation. The RT6278B operates in Forced
PWM that helps meet tight voltage regulation accuracy
requirements. The RT6278A/B 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 RT6278A/B 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 23V
Output Voltage Range : 0.6V to 6V
Advanced Constant On-Time (ACOT
TM
) Control
�½
�½
Ultrafast Transient Response
No Needs For External Compensations
�½
Optimized for Low-ESR Ceramic Output Capacitors
0.6V
±
1% High-Accuracy Feedback Reference
Voltage
Optional for Operation Modes :
Power Saving Mode (PSM) (RT6278A)
�½
Forced PWM Mode (RT6278B)
�½
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
Ultrasonic Mode (USM) for RT6278A
Available In UQFN-12HL 3x3 (FC) (U-Type) Package
Ordering Information
RT6278A/B
Package Type
QUF : UQFN-12HL 3x3 (FC) (U-Type)
Lead Plating System
G : Green (Halogen Free and Pb Free)
UVP Option
H : Hiccup
PWM Operation Mode
A : Automatic PSM
B: Forced PWM
Note :
Richtek products are :
�½
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
RoHS compliant and compatible with the current require-
ments of IPC/JEDEC J-STD-020.
Suitable for use in SnPb or Pb-free soldering processes.
�½
Copyright
©
2018 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS6278A/B-01 May 2018
www.richtek.com
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RICHTEK [ RICHTEK TECHNOLOGY CORPORATION ]
