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Richtek |
RT9277C/D
High Performance, Low Noise Boost Converter
General Description
Features
The RT9277C/D is a high performance, low noise, fixed
frequency step up DC-DC Converter. The RT9277C/D
converters input voltage ranging 2.5V to 5.5V into output
voltage up to 16V. Current mode control with external
compensation network makes it easy to stabilize the
system and keep maximum flexibility. Soft start function
minimizes impact on the input power system. Internal power
MOSFET with very low RDS(ON) provides high efficiency.
The RT9277C/D with 640kHz and 1.2MHz operation
frequency options provide flexibiltity of minimum output
inductor size, maximum efficiency and low BOM cost.
z Efficiency up to 90%
z VIN Operating Range : 2.5V to 5.5V
z 1.6A, 0.2Ω, 16V Internal Power MOSFET
z 640kHz and 1.2MHz Operation Frequency
z External Compensation
z Internal/External Programmable Soft Start
z Small MSOP8 Package
z OCP and OTP Function are Included
z RoHS Compliant and Halogen Free
Applications
The RT9277C/D also provides comprehensive protection
functions such as UVLO, OCP and OTP.
Ordering Information
RT9277C/D
Package Type
F : MSOP-8
QW : WDFN-8L 3x3 (W-Type)
Lead Plating System
G : Green (Halogen Free and Pb Free)
Note :
Soft Start Function
C : External Programmable
D : Internal Programmable
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.
z TFT LCD panel
z OLEDDisplay
z PCMCIA Cards
z Portable Device
Pin Configurations
(TOP VIEW)
COMP
FB
EN
GND
8
27
36
45
MSOP-8
SS
FREQ
VIN
LX
COMP 1
FB 2
EN 3
GND 4
8 SS
7 FREQ
6 VIN
9 5 LX
RT9277C
WDFN-8L 3x3
Marking Information
For marking information, contact our sales representative
directly or through a Richtek distributor located in your
area.
COMP
FB
EN
GND
8
27
36
45
MSOP-8
NC
FREQ
VIN
LX
COMP 1
FB 2
EN 3
GND 4
8 NC
7 FREQ
6 VIN
9 5 LX
RT9277D
WDFN-8L 3x3
DS9277C/D-01 April 2011
www.richtek.com
1
RT9277C/D
Typical Application Circuit
VIN
2.5V to 5.5V
C1
L1 D1
5 LX
GND 4
6 VIN
EN 3
7 FREQ FB 2
8 SS COMP 1
C5 RT9277C
Chip Enable
C2
R3
C4 C3
VOUT
R1
R2
Figure 1
VIN
2.5V to 5.5V
C1
Chip Enable
L1 D1
5 LX
6 VIN
GND 4
EN 3
VOUT
C2
R1
7 FREQ FB 2
8 NC COMP 1
R3
RT9277D
C4 C3
R2
Figure 2
Table 1. Recommended Components
Symbol
(unit)
VIN VOUT FOSC
(V) (V) (Hz)
Application 1 3.3
9 1.2M
Application 2 3.3
12 1.2M
Application 3 3.3
12 640K
C1
(μF)
10
10
10
L1
(μH)
4.7(TDK SLF6028)
4.7(TDK SLF6028)
10(TDK SLF6028)
C2
(μF)
33 (ceramic)
33 (ceramic)
33 (ceramic)
R3
(kΩ)
82
180
120
C3
(pF)
82 0
68 0
1200
C4
(pF)
10
22
22
Function Block Diagram
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2
EN
COMP
FB
FREQ
LX
VIN Protection
VFB
1.24V
Error
Amplifier
-
+
Summing
Comparator
-
+
5µA
Oscillator
Slope
Compen-
sation
Clock
4µA
Soft-
Start
Control
and
Driver
Logic
N
Current
Sense
RT9277C
VIN
SS
LX
GND
DS9277C/D-01 April 2011
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