RT8278 Datasheet, PDF (1/16 Pages) Richtek Technology Corporation – 2A, 24V, 3MHz Step-Down Converter

RT8278
2A, 24V, 3MHz Step-Down Converter
General Description
The RT8278 is a high voltage buck converter that can
support an input voltage range from 4.5V to 24V with output
current up to 2A. Current mode operation provides fast
transient response and eases loop stabilization.
The chip provides protection functions such as cycle-by-
cycle current limiting and thermal shutdown protection.
In shutdown mode, the regulator only draws 25μA of
supply current. The RT8278 is available in a SOP-8
(Exposed Pad) package.
Ordering Information
RT8278
Package Type
SP : SOP-8 (Exposed Pad-Option 1)
Lead Plating System
G : Green (Halogen Free and Pb Free)
Note :
Richtek products are :
` 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.
Marking Information
RT8278GSP : Product Number
RT8278
GSPYMDNN
YMDNN : Date Code
Features
Wide Operating Input Range : 4.5V to 24V
Adjustable Output Voltage Range : 0.8V to 15V
Output Current up to 2A
25μA Low Shutdown Current
High Efficiency up to 90% at 2.2MHz
Programmable Frequency : 220kHz to 3MHz
Internal Soft-Start
Stable with Low ESR Output Ceramic Capacitors
Thermal Shutdown Protection
Cycle-By-Cycle Over Current Protection
RoHS Compliant and Halogen Free
Applications
DSL Modem for ADSL2+ Standard
Distributed Power Systems
Pre-Regulator for Linear Regulators
Pin Configurations
(TOP VIEW)
BOOT
VIN
SW
GND
8
2
7
GND
3
6
9
4
5
RT
EN
COMP
FB
SOP8 (Exposed Pad)
Typical Application Circuit
V_IN
4.5V to 24V
Chip Enable
C_IN
10µF
2 _VIN
BOOT ¹
7 _EN
RT8278
SW ³
8 _RT
R_RT
24K
4,
9 (Exposed Pad)
GND
FB ⁵
COMP ⁶
DS8278-02 March 2011
C_{BOOT L}
10nF 2.2µH
D
B220A
R1
31.6k
V_OUT
3.3V/2A
C_OUT
22µF
C_C
1nF
R_C
36k
R2
10k
NCC_P
www.richtek.com
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