DC/DC Converter. RT8509 Datasheet

RT8509 Converter. Datasheet pdf. Equivalent

RT8509 Datasheet
Recommendation RT8509 Datasheet
Part RT8509
Description Step-Up DC/DC Converter
Feature RT8509; ® RT8509 3A, 14V Step-Up DC/DC Converter General Description The RT8509 is a high performance swit.
Manufacture Richtek
Datasheet
Download RT8509 Datasheet




Richtek RT8509
®
RT8509
3A, 14V Step-Up DC/DC Converter
General Description
The RT8509 is a high performance switching boost
converter that provides a regulated supply voltage for active
matrix thin film transistor (TFT) liquid crystal displays
(LCDs).
The RT8509 incorporates current mode, fixed-frequency,
pulse width modulation (PWM) circuitry with a built in
N-MOSFET to achieve high efficiency and fast transient
response.
The RT8509 has a wide input voltage range from 2.8V to
14V. In addition, the output voltage can be adjusted up to
24V via an external resistive voltage divider. The maximum
peak current is limited to 4.5A (typ.). Other features include
programmable soft-start, over voltage protection, and over
temperature protection.
The RT8509 is available in a WDFN-10L 3x3 package.
Ordering Information
RT8509
Package Type
QW : WDFN-10L 3x3 (W-Type)
Note :
Lead Plating System
G : Green (Halogen Free and Pb Free)
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.
Features
z 90% Efficiency
z Adjustable Output Up to 24V
z 2.8V to 14V Input Supply Voltage
z Input Supply Under Voltage Lockout
z Fixed 1.2MHz Switching Frequency
z Programmable Soft-Start
z VOUT Over Voltage Protection
z Over Temperature Protection
z Thin 10-Lead WDFN Package
z RoHS Compliant and Halogen Free
Applications
z GIP TFT LCD Panels
Pin Configurations
(TOP VIEW)
COMP 1
FB 2
EN 3
GND 4
GND 5
10 SS
9 VIN
8 VSUP
7 LX
11 6 LX
WDFN-10L 3x3
Marking Information
H4=YM
DNN
H4= : Product Code
YMDNN : Date Code
Typical Application Circuit
VIN
12V CIN
10µF x 2 R4
10
L1
4.7µH
D1
6, 7
LX VSUP 8
Chip Enable
C2 9 VIN RT8509
1µF
3 EN
FB 2
SS 10
4, 5, 11 (Exposed Pad) GND
COMP 1
C3
1µF
R3
56k
R1
134k
VOUT
COUT 18V
4.7µF x 3
R2
10k
CSS
33nF
C1
1nF
Copyright ©2012 Richtek Technology Corporation. All rights reserved.
DS8509-01 March 2012
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
1



Richtek RT8509
RT8509
Functional Pin Description
Pin No.
1
Pin Name
Pin Function
COMP Compensation Pin for Error Amplifier. Connect a series RC from COMP to ground.
Feedback. The FB regulation voltage is 1.25V nominal. Connect an external
2
FB
resistive voltage divider between the step-up regulator’s output (VOUT) and GND,
with the center tap connected to FB. Place the divider close to the IC and minimize
the trace area to reduce noise coupling.
3 EN Chip Enable. Drive EN low to turn off the Boost.
4, 5,
11 (Exposed Pad)
GND
Ground. The Exposed Pad must be soldered to a large PCB and connected to
GND for maximum power dissipation.
6, 7
LX
Switch. LX is the drain of the internal MOSFET. Connect the inductor/rectifier diode
junction to LX and minimize the trace area for lower EMI.
8
VSUP
Boost Converter Over Voltage Protection Input. Bypass VSUP with a minimum 1μF
ceramic capacitor directly to GND.
9 VIN Supply Input . Bypass VIN with a minimum 1μF ceramic capacitor directly to GND.
Soft-Start Control. Connect a soft-start capacitor (CSS) to this pin. The soft-start
10 SS capacitor is charged with a constant current of 5μA. The soft-start capacitor is
discharged to ground when EN is low.
Function Block Diagram
VIN
EN
COMP
FB
VSUP
OVP
LX
OTP
Protection
Soft
Start
Error Amplifier
+
1.25V -
VDD
Summing
Comparator
-
+
Clock
Control
and
Driver
Logic
Oscillator
Slope
Compensation
Current
Sense
SS
LX
GND
Copyright ©2012 Richtek Technology Corporation. All rights reserved.
www.richtek.com
2
is a registered trademark of Richtek Technology Corporation.
DS8509-01 March 2012



Richtek RT8509
RT8509
Absolute Maximum Ratings (Note 1)
z LX, VSUP to GND --------------------------------------------------------------------------------------------------------- 0.3V to 28V
z VIN, EN to GND ------------------------------------------------------------------------------------------------------------ 0.3V to 16.5V
z Other Pins to GND -------------------------------------------------------------------------------------------------------- 0.3V to 6.5V
z Power Dissipation, PD @ TA = 25°C
WDFN-10L 3x3 ------------------------------------------------------------------------------------------------------------- 1.429W
z Package Thermal Resistance (Note 2)
WDFN-10L 3x3, θJA ------------------------------------------------------------------------------------------------------- 70°C/W
WDFN-10L 3x3, θJC ------------------------------------------------------------------------------------------------------- 8.2°C/W
z Junction Temperature ----------------------------------------------------------------------------------------------------- 150°C
z Storage Temperature Range -------------------------------------------------------------------------------------------- 65°C to 150°C
z Lead Temperature (Soldering, 10sec.) -------------------------------------------------------------------------------- 260°C
z ESD Susceptibility (Note 3)
HBM (Human Body Model) ---------------------------------------------------------------------------------------------- 2kV
MM (Machine Model) ----------------------------------------------------------------------------------------------------- 200V
Recommended Operating Conditions (Note 4)
z Ambient Temperature Range -------------------------------------------------------------------------------------------- 40°C to 85°C
z Junction Temperature Range -------------------------------------------------------------------------------------------- 40°C to 125°C
Electrical Characteristics
(VIN = 3.3V, VOUT = 10V, TA =25°C unless otherwise specified)
Parameter
Symbol
Test Conditions
Supply Current
Input Voltage Range
Output Voltage Range
Under Voltage Lockout
Threshold
UVLO Hysteresis
VIN
VOUT
VUVLO
ΔVUVLO
VIN Quiescent Current
IQ
Thermal Shutdown Threshold TSD
Thermal Shutdown
Hysteresis
ΔTSD
VSUP Over Voltage
Threshold
Oscillator
Oscillator Frequency
Maximum Duty Cycle
fOSC
DMAX
Error Amplifier
VIN Rising
VFB = 1.3V, LX Not Switching
VFB = 1V, LX Switching
Temperature Rising
VSUP Rising
FB Regulation Voltage
FB Input Bias Current
FB Line Regulation
VREF
IFB
Min Typ Max Unit
2.8 -- 14 V
-- -- 24 V
-- 2.5 3 V
-- 200 -- mV
-- 1 -- mA
-- 5 --
-- 155 -- °C
-- 10 -- °C
-- 26 -- V
1000
--
1200
90
1500
--
kHz
%
-- 1.25 --
V
-- -- 100 nA
-- 0.05 0.2 %/V
Copyright ©2012 Richtek Technology Corporation. All rights reserved.
DS8509-01 March 2012
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
3







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