Richtek RT8463GCP, RT8463GQW Schematic [ru]
®
RT8463
High Voltage Multi-Topology LED Driver
General Description
The RT8463 is a current mode PWM regulator for LED driving applications. With a 2A power switch, wide input voltage (4.5V to 50V) and output voltage (up to 50V) ranges, the RT8463 can operate in any of the three common topologies : Buck, Boost or Buck-Boost.
With 470kHz operating frequency, the size of the external PWM inductor and input/output capacitors can be minimized. High efficiency is achieved by a 100mV current sensing control.
Brightness dimming can be controlled from either analog or PWM signal. A unique built-in clamping comparator and filtering resistor allow easy low noise analog dimming conversion from PWM signal with only one external capacitor.
The RT8463 is available in the TSSOP-14 (Exposed pad) and WDFN-12L 3x3 packages.
Features
zHigh Voltage : VIN Up to 50V, VOUT Up to 50V
zBuck, Boost or Buck-Boost Operation
zBuilt-In 2A Power Switch
zCurrent Mode PWM Control
z470kHz Fixed Switching Frequency
zEasy Dimming : Analog, PWM Digital or PWM Converting to Analog with One External Capacitor
zAdjustable Soft-Start to Avoid Inrush Current
zAdjustable Over Voltage Protection to Limit Output Voltage
zThermal Shutdown
zUnder Voltage Lockout
zRoHS Compliant and Halogen Free
Applications
zGPS, Portable DVD Backlight
zDesk Lights and Room Lighting
zIndustrial Display Backlight
Ordering Information
RT8463
Package Type
CP : TSSOP-14 (Exposed Pad)
QW : WDFN-12L 3x3 (W-Type)
Lead Plating System
G : Green (Halogen Free and Pb Free)
Note :
Richtek products are :
`RoHS compliant and compatible with the current requirements of IPC/JEDEC J-STD-020.
`Suitable for use in SnPb or Pb-free soldering processes.
Marking Information
RT8463GCP
RT8463GCP : Product Number
RT8463 YMDNN : Date Code
GCPYMDNN
RT8463GQW
98 = : Product Code
98=YM YMDNN : Date Code
DNN
Simplified Application Circuit
L |
D1 |
VIN |
VOUT |
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C1 |
RT8463 |
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C6 |
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VCC |
SW |
R2 |
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5V |
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EN |
ISP |
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PWM |
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DCTL |
ISN |
R3 |
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Dimming Control |
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VC |
OVP |
VOUT |
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R1 |
C3 |
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SS |
CREG |
R4 |
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C4 |
ACTL |
GND |
C5 |
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C2 |
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Copyright ©2013 Richtek Technology Corporation. All rights reserved. |
is a registered trademark of Richtek Technology Corporation. |
DS8463-00 January 2013 |
www.richtek.com |
|
1 |
RT8463
Pin Configurations
(TOP VIEW)
ISP |
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14 |
VCC |
ISN |
2 |
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13 |
CREG |
VC |
3 |
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12 |
SW |
ACTL |
4 |
GND |
11 |
GND |
DCTL |
5 |
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10 |
SS |
EN |
6 |
15 |
9 |
OVP |
GND |
7 |
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8 |
GND |
TSSOP-14 (Exposed Pad)
ISP 1 |
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12 |
VCC |
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ISN 2 |
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11 |
CREG |
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VC 3 |
GND |
10 |
SW |
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ACTL 4 |
9 |
GND |
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DCTL 5 |
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8 |
SS |
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EN 6 |
13 7 |
OVP |
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WDFN-12L 3x3
Functional Pin Description
Pin No. |
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TSSOP-14 |
WDFN-12L 3x3 |
Pin Name |
Pin Function |
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(Exposed Pad) |
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1 |
1 |
ISP |
Positive Current Sense Input. |
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2 |
2 |
ISN |
Negative Current Sense Input. Voltage threshold between ISP and |
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ISN is 100mV. |
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3 |
3 |
VC |
Compensation Node for PWM Boost Converter Loop. |
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4 |
4 |
ACTL |
Analog Dimming Control Input. Effective programming range is |
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between 0.2V and 1.2V. |
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Digital Dimming Control Input. By adding a 0.47μF filtering |
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5 |
5 |
DCTL |
capacitor on the ACTL pin, the PWM dimming signal on DCTL pin |
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will be averaged and converted into analog dimming signal on the |
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ACTL pin. VACTL = 1.2V x PWM dimming duty cycle. |
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6 |
6 |
EN |
Enable Control Input (Active High). When this pin is low, the chip is |
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in shutdown mode. |
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7, 8, 11, 15 |
9, |
GND |
Ground. The exposed pad must be soldered to a large PCB and |
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(Exposed Pad) |
13 (Exposed Pad) |
connected to GND for maximum power dissipation. |
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9 |
7 |
OVP |
Over Voltage Protection Sense Input. The PWM Boost converter |
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turns off when VOVP goes higher than 1.2V. |
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10 |
8 |
SS |
Soft-Start Time Setting. A minimum 10nF capacitor is required for |
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soft-start. |
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12 |
10 |
SW |
Switch Node of PWM Boost Converter. |
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13 |
11 |
CREG |
Regulator Output for Internal Circuit. Placed a 1μF |
capacitor to |
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stabilize the 5V output regulator. |
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14 |
12 |
VCC |
Power Supply Voltage Input. For good bypass, |
a low ESR |
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capacitor is required. |
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Copyright ©2013 Richtek Technology Corporation. All rights reserved. |
is a registered trademark of Richtek Technology Corporation. |
www.richtek.com |
DS8463-00 January 2013 |
2
RT8463
Function Block Diagram
VCC |
- |
OSC |
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4.5V |
+ |
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OVP |
+ |
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1.2V |
- |
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EN |
+ |
Shutdown |
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1.4V |
- |
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VC |
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5µA |
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SS |
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1.2V |
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DCTL |
+ |
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- |
SW
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5V |
CREG |
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S |
LDO |
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R |
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R |
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+ -
GM- |
ISN |
+ |
ISP |
+
-
GND
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ACTL |
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VISP – VISN |
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(mV) |
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100 |
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0 |
0.2 |
1.2 |
VACTL (V) |
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Figure 1
Operation
The RT8463 is specifically designed to be operated in Buck, Boost and Buck-Boost converter applications. This device uses a fixed frequency, current mode control scheme to provide excellent line and load regulations. The control loop has a current sense amplifier to sense the voltage between the ISP and ISN pins and provides an output voltage at the VC pin. A PWM comparator then turns off the internal power switch when the sensed power switch current exceeds the compensated VC pin voltage. The power switch will not reset by the oscillator clock in each cycle. If the comparator does not turn off the switch in a cycle, the power switch is on for more than a full
switching period until the comparator is tripped. In this manner, the programmed voltage across the sense resistor is regulated by the control loop.
The current through the sense resistor is set by the programmed voltage and the sense resistance. The voltage across the sense resistor can be programmed by either the analog or PWM signals at the ACTL pin, or the PWM signal at the DCTL pin.
The RT8463 provides protection functions which include over temperature, input voltage under voltage, output voltage over voltage, and switch current limit.
Copyright ©2013 Richtek Technology Corporation. All rights reserved. |
is a registered trademark of Richtek Technology Corporation. |
DS8463-00 January 2013 |
www.richtek.com |
|
3 |
RT8463
Absolute Maximum Ratings (Note 1)
z Supply Input Voltage, VCC ------------------------------------------------------------------------------------ |
−0.3V to 60V |
z SW Pin Voltage at Switching Off, ISP, ISN ---------------------------------------------------------------- |
−0.3V to 60V |
z DCTL, ACTL, CREG, OVP Pin Voltage -------------------------------------------------------------------- |
−0.3V to 5.5V (Note 2) |
z EN Pin Voltage --------------------------------------------------------------------------------------------------- |
−0.3V to 20V |
z Power Dissipation, PD @ TA = 25°C |
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TSSOP-14 (Exposed Pad) ------------------------------------------------------------------------------------ |
3.32W |
WDFN-12L 3x3 --------------------------------------------------------------------------------------------------- |
3.28W |
z Package Thermal Resistance (Note 3) |
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TSSOP-14 (Exposed Pad), θJA ------------------------------------------------------------------------------ |
30.1°C/W |
TSSOP-14 (Exposed Pad), θJC ------------------------------------------------------------------------------ |
7.5°C/W |
WDFN-12L 3x3, θJA --------------------------------------------------------------------------------------------- |
30.5°C/W |
WDFN-12L 3x3, θJC --------------------------------------------------------------------------------------------- |
7.5°C/W |
z Junction Temperature ------------------------------------------------------------------------------------------- |
150°C |
z Lead Temperature (Soldering, 10 sec.) --------------------------------------------------------------------- |
260°C |
z Storage Temperature Range ---------------------------------------------------------------------------------- |
−65°C to 150°C |
z ESD Susceptibility (Note 4) |
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HBM (Human Body Model) ------------------------------------------------------------------------------------ |
2kV |
MM (Machine Model) ------------------------------------------------------------------------------------------- |
200V |
Recommended Operating Conditions |
(Note 5) |
z Supply Input Voltage, VCC ------------------------------------------------------------------------------------ |
4.5V to 50V |
z Junction Temperature Range ---------------------------------------------------------------------------------- |
−40°C to 125°C |
z Ambient Temperature Range ---------------------------------------------------------------------------------- |
−40°C to 85°C |
Electrical Characteristics
(VCC = 12V, No Load on any Output, TA = 25°C, unless otherwise specified)
Parameter |
Symbol |
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Test Conditions |
Min |
Typ |
Max |
Unit |
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Overall |
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Regulator Output Voltage |
VCREG |
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ICREG = 20mA |
4.5 |
5 |
5.5 |
V |
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Supply Current |
IVCC |
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VC ≤ 0.2V (Not Switching ) |
-- |
-- |
5 |
mA |
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VIN Under Voltage Lockout |
VUVLO |
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VIN Rising |
-- |
4.2 |
-- |
V |
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Threshold |
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VIN Falling |
-- |
3.8 |
-- |
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Shutdown Current |
ISHDN |
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VEN < 0.5V |
-- |
-- |
15 |
μA |
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EN Input Voltage |
Logic-High |
VEN_H |
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2 |
-- |
-- |
V |
Logic-Low |
VEN_L |
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-- |
-- |
0.5 |
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EN Input Current |
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VEN > 2V |
-- |
-- |
1 |
μA |
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Current Sense Amplifier |
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Input Threshold (VISP − VISN) |
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VACTL ≥ 1.25V |
96 |
100 |
102 |
mV |
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VACTL = 1.2V |
95 |
98 |
101 |
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Copyright ©2013 Richtek Technology Corporation. All rights reserved. |
is a registered trademark of Richtek Technology Corporation. |
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www.richtek.com |
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DS8463-00 January 2013 |
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4
RT8463
Parameter |
Symbol |
Test Conditions |
Min |
Typ |
Max |
Unit |
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Input Current |
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IISP |
VISP = 24V |
-- |
200 |
-- |
μA |
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Input Current |
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IISN |
VISN = 24V |
-- |
20 |
-- |
μA |
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Output Current |
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IVC |
2V > VC > 0.2V |
-- |
±10 |
-- |
μA |
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VC Threshold for PWM Switch Off |
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-- |
0.2 |
-- |
V |
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LED Dimming |
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Analog Dimming ACTL Pin Input |
IACTL |
0 ≤ VACTL ≤ 3V, DCTL Floating |
-- |
-- |
2 |
μA |
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Current |
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LED Current On Threshold at |
VACTL_ON |
(VISP − VISN) = 100mV |
-- |
1.2 |
1.33 |
V |
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ACTL |
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LED Current Off Threshold at |
VACTL_OFF |
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-- |
0.2 |
0.25 |
V |
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ACTL |
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DCTL Input Current |
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IDCTL |
0.3V ≤ VDCTL ≤ 5V |
-- |
0.5 |
2 |
μA |
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DCTL Input |
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Logic-High |
VDCTL_H |
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2 |
-- |
-- |
V |
Voltage |
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Logic-Low |
VDCTL_L |
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-- |
-- |
0.1 |
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PWM Boost Converter |
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Switching Frequency |
fSW |
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420 |
470 |
520 |
kHz |
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Maximum Duty Cycle |
DMAX |
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-- |
-- |
100 |
% |
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Minimum On-Time |
(Note 6) |
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-- |
150 |
250 |
ns |
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SW RDS(ON) |
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-- |
0.3 |
0.5 |
Ω |
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SW Current Limit |
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ILIM_SW |
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2 |
2.5 |
-- |
A |
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OVP and Soft-Start |
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OVP Threshold |
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VOVP |
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1.15 |
1.2 |
1.25 |
V |
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OVP Input Current |
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IOVP |
VOVP ≤ 1.5V |
-- |
-- |
50 |
nA |
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Soft-Start SS Pin Current |
ISS |
VSS ≤ 2.5V |
-- |
5 |
8 |
μA |
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Temperature Protection |
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Thermal Shutdown Temperature |
TSD |
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-- |
150 |
-- |
°C |
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Thermal Shutdown Hysteresis |
TSD |
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-- |
20 |
-- |
°C |
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Note 1. Stresses beyond those listed “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions may affect device reliability.
Note 2. If connected with a 20kΩ serial resistor, ACTL and DCTL can go up to 40V.
Note 3. θJA is measured at TA = 25°C on a high effective thermal conductivity four-layer test board per JEDEC 51-7. θJC is measured at the exposed pad of the package.
Note 4. Devices are ESD sensitive. Handling precaution is recommended.
Note 5. The device is not guaranteed to function outside its operating conditions. Note 6. Guaranteed by design, not subjected to production test.
Copyright ©2013 Richtek Technology Corporation. All rights reserved. |
is a registered trademark of Richtek Technology Corporation. |
DS8463-00 January 2013 |
www.richtek.com |
|
5 |
RT8463
Typical Application Circuit
VIN |
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D1 |
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4.5V to 50V |
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C1 |
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RT8463 |
R2 |
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VCC |
ISP |
100mV |
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5V |
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EN |
ISN |
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R3 |
R4 |
PWM |
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DCTL |
OVP |
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Dimming control |
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GND |
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C6 |
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VC |
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CREG |
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R1 |
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C5 |
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SS |
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1µF |
L |
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10k |
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C3 |
ACTL |
SW |
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22µH |
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C2 |
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10nF |
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3.3nF |
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C4 |
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0.47µF |
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Figure 2. PWM to Analog Dimming Buck Configuration
VIN |
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D1 |
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4.5V to 50V |
C1 |
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RT8463 |
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R2 |
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VCC |
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ISP |
100mV |
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Analog |
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ACTL |
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ISN |
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R3 |
R4 |
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Dimming |
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DCTL |
OVP |
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5V |
EN |
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GND |
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C6 |
CREG |
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VC |
C5 |
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R1 |
SS |
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1µF |
L |
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10k |
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SW |
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15µH |
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C2 |
C3 |
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10nF |
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3.3nF |
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Figure 3. Analog Dimming Buck Configuration
VIN |
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D1 |
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4.5V to 50V |
C1 |
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RT8463 |
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R2 |
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VCC |
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ISP |
100mV |
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PWM |
ACTL |
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ISN |
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R3 |
R4 |
Dimming control |
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OVP |
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DCTL |
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5V |
EN |
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GND |
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C6 |
CREG |
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VC |
C5 |
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R1 |
SS |
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1µF |
L |
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10k |
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15µH |
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C3 |
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SW |
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C2 |
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10nF |
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3.3nF |
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Figure 4. PWM Dimming Buck Configuration Through ACTL Pin
Copyright ©2013 Richtek Technology Corporation. All rights reserved. |
is a registered trademark of Richtek Technology Corporation. |
www.richtek.com |
DS8463-00 January 2013 |
6
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