LED Driver. RT8453 Datasheet

RT8453 Driver. Datasheet pdf. Equivalent

RT8453 Datasheet
Recommendation RT8453 Datasheet
Part RT8453
Description High Voltage Buck LED Driver
Feature RT8453; Conceptual RT8453 High Voltage BUCK LED Driver General Description The RT8453 is a Buck current m.
Manufacture Richtek
Datasheet
Download RT8453 Datasheet




Richtek RT8453
Conceptual
RT8453
High Voltage BUCK LED Driver
General Description
The RT8453 is a Buck current mode PWM regulator for
LED driving applications. It has a 1.5A switch on board
and can be operated with wide input range from 4.5V to
40V. With a 800kHz operating frequency, the external
PWMinductor and input/output capacitors can all be small.
High efficiency is achieved with a 190mV current sensing.
Dimming can be either analog or PWM digital signal driven.
The RT8453 is available in SOP8 (Exposed pad) package.
Features
z High Voltage : VIN up to 40V
z 1.5A Switch Current
z Current Mode PWM with 800kHz Switching
z Frequency
z Easy Dimming : Analog or Digital method
z Programmable Soft Start to Avoid Inrush Current
z VIN Under Voltage Lockout and Thermal Shutdown
z RoHS Compliant and Halogen Free
Ordering Information
RT8453
Package Type
SP : SOP-8 (Exposed Pad-Option 2)
Operating Temperature Range
G : Green (Halogen Free with Comme-
rcial Standard)
Note :
Richtek Green 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.
Applications
z GPS, Portable DVD Backlight
z Desk Lights and Room Lighting
z Industrial Display Backlight
Pin Configurations
(TOP VIEW)
ISN
VC
ACTL
EN
8
27
GND
36
9
45
VCC
SW
GND
SS
SOP-8 (Exposed Pad)
Typical Application Circuit
VIN
4.5V to 40V
Analog
Dimming
5V
R1
10k
C2
3.3nF
C1
RT8453
8 VCC
ISN 1
3 ACTL
R2
190mV
R3 R4
4 EN
2 VC
5 SS
C3
10nF
SW 7
L
22uH
6, Exposed Pad (9)
GND
C4
Figure 1. Analog Dimming BUCK Configuration
DS8453-00C March 2009
www.richtek.com
1



Richtek RT8453
RT8453
Conceptual
VIN
4.5V to 40V
PWM
Dimming control
5V
R1
10k
C2
3.3nF
C1
RT8453
8 VCC
ISN 1
3 ACTL
R2
190mV
4 EN
2 VC
5 SS
C3
10nF
SW 7
L
22uH
6, Exposed Pad (9)
GND
R3 R4
C4
Figure 2. Digital Dimming BUCK Configuration Through ACTL Pin
Functional Pin Description
Pin No.
Pin Name
Pin Function
1
ISN
Current Sense Amplifier Negative Input. Voltage threshold between VCC and ISN is
190mV.
2 VC
PWM Converter Loop Compensation Node.
3
ACTL
Analog Dimming Control. Effective programming range is between 0.3V and 1.2V.
4 EN
Chip Enable (Active High). When low, chip is in shutdown mode.
5 SS
Soft Start. A capacitor of at least 10nF is required for soft start.
6,
9 (Exposed Pad)
GND
Ground. The exposed pad must be soldered to a large PCB and connected
to GND for maximum power dissipation.
7 SW PWM Converter Switch Node.
8
VCC
Power Supply of the Chip. For good bypass, a low ESR capacitor is required.
www.richtek.com
2
DS8453-00C March 2009



Richtek RT8453
Function Block Diagram
Conceptual
VCC
EN
VC
SS
ACTL
4.5V
1.4V
OSC
-
+
+ Shutdown
-
6uA
+
-
S
R
R
-
GM
+
SW
VCC
RT8453
ISN
GND
VCC – VISN
(mV)
190
0 0.3
1.2
Figure 3
VACTL (V)
DS8453-00C March 2009
www.richtek.com
3







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