DC/DC Converter. RT8509A Datasheet

RT8509A Converter. Datasheet pdf. Equivalent

RT8509A Datasheet
Recommendation RT8509A Datasheet
Part RT8509A
Description Step-Up DC/DC Converter
Feature RT8509A; ® RT8509A 4.5A Step-Up DC/DC Converter General Description The RT8509A is a high performance switc.
Manufacture Richtek
Datasheet
Download RT8509A Datasheet




Richtek RT8509A
®
RT8509A
4.5A Step-Up DC/DC Converter
General Description
The RT8509A 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 RT8509A 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 RT8509A 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 (min.). Other features
include adjustable soft-start, over-voltage protection, and
over-temperature protection.
The RT8509A is available in the WDFN-12L 5x5 package.
Marking Information
RT8509A
GQW
YMDNN
RT8509AGQW : Product Number
YMDNN : Date Code
Features
90% Efficiency
Adjustable Output Up to 24V
2.8V to 14V Input Supply Voltage
Input Supply Under-Voltage Lockout
Fixed 1.2MHz Switching Frequency
Adjustable Soft-Start
VOUT Over-Voltage Protection
Over-Temperature Protection
Thin 12-Lead WDFN Package
RoHS Compliant and Halogen Free
Applications
GIP TFT-LCD Panels
Ordering Information
RT8509A
Package Type
QW : WDFN-12L 5x5 (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.
Simplified Application Circuit
L1 D1
VIN
VOUT
CIN R4
LX
VIN VOUT
C2
RT8509A
FB
R1
C3
R2
COUT
Enable
EN
GND
SS
COMP
R3
CSS
C1
Copyright ©2013 Richtek Technology Corporation. All rights reserved.
DS8509A-00 November 2013
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
1



Richtek RT8509A
RT8509A
Pin Configurations
(TOP VIEW)
COMP 1
FB 2
EN 3
GND 4
GND 5
GND 6
GND
13
12 SS
11 VIN
10 VOUT
9 GND
8 LX
7 LX
WDFN-12L 5x5
Functional Pin Description
Pin No.
1
2
3
Pin Name
Pin Function
COMP
Compensation Node for Error Amplifier. Connect a series RC from COMP to
ground.
Feedback Voltage Input. The FB regulation voltage is 1.25V nominal. Connect an
FB
external 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.
EN Enable Control Input. Drive EN low to turn off the Boost.
4, 5, 6, 9,
13 (Exposed Pad)
GND
Ground. The Exposed Pad must be soldered to a large PCB and connected to
GND for maximum power dissipation.
7, 8 LX
Switch Node. LX is the Drain of the internal MOSFET. Connect the
inductor/rectifier diode junction to LX and minimize the trace area for lower EMI.
10
VOUT
Over-Voltage Protection Input for Boost Converter. Bypass VOUT with a
minimum 1F ceramic capacitor directly to GND.
11
VIN
Supply Voltage Input. Bypass VIN with a minimum 1μF ceramic capacitor directly
to GND.
12 SS
Soft-Start Time Setting. Connect a soft-start capacitor (CSS) to this pin. The
soft-start capacitor is charged with a constant current of 5A. The soft-start
capacitor is discharged to ground when EN is low.
Copyright ©2013 Richtek Technology Corporation. All rights reserved.
www.richtek.com
2
is a registered trademark of Richtek Technology Corporation.
DS8509A-00 November 2013



Richtek RT8509A
Function Block Diagram
VIN
EN
COMP
FB
VOUT
OVP
LX
OTP
Protection
Soft
Start
Error Amplifier
+
1.25V -
VDD
Summing
Comparator
-
+
Clock
Control
and
Driver
Logic
Oscillator
Slope
Compensation
Current
Sense
Operation
The RT8509A is a high-performance step-up DC/DC
converter that provides a regulated and high precision
supply voltage. It incorporates current mode, fixed-
frequency, pulse-width modulation (PWM) circuitry with
a built-in N-Channel power MOSFET to achieve high
efficiency and fast transient response. The device features
an adjustable soft start time using an external soft-start
capacitor to reduce in-rush current.
RT8509A
SS
LX
GND
Copyright ©2013 Richtek Technology Corporation. All rights reserved.
DS8509A-00 November 2013
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
3







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