RT8566 - Richtek

®
RT8566
High Voltage 8-CH LED Driver
General Description
Features
The RT8566 is an 8-CH LED driver capable of delivering
120mA for each channel. The RT8566 is a current mode
boost converter with an adjustable switching frequency
via the RT pin from 100kHz to 1MHz and a wide VIN
range from 9V to 28V.

Wide Input Supply Voltage Range : 9V to 28V

Adjustable Boost Controller Switching Frequency
from 100kHz to 1MHz
Programmable Channel Current
Channel Current Matching : ±1.5%
External Dimming Control
Boost MOSFET Over Current Protection
Automatic LED Open/Short Protection to Avoid
Output Over Voltage
VCC Under Voltage Lockout
Adjustable Over Voltage Protection
Under Voltage Protection
Thermal Shutdown Protection
Abnormal Status Indicator for Open/Short/Thermal
Condition
RoHS Compliant and Halogen Free
The PWM output voltage loop selects and regulates the
LED pin with the highest voltage string to 0.6V, hence
allowing voltage mismatches between LED strings. The
RT8566 automatically detects and disconnects any
unconnected and/or broken strings during operation from
PWM loop to prevent VOUT from over voltage. The 1.5%
matched LED currents on all channels are simply
programmed with a resistor. A very high contrast ratio true
digital PWM dimming can be achieved by driving the PWM
pin with a PWM signal.











When an abnormal situation (open/short/thermal) occurs,
a status signal will be sent to the system to shut down
the IC.
Applications

The RT8566 is available in a TSSOP-28 (Exposed Pad)
package.
Ordering Information
RT8566
Package Type
CP : TSSOP-28 (Exposed Pad-Option 1)
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


LCD TV, Monitor Display Backlight
LED Driver Application
General Purpose Constant Current Source
Pin Configurations
(TOP VIEW)
OVP/UVP
RISET
NC
PWM
NC
STATUS
NC
RT
VC
SS
EN
SEN
PGND
DRV
28
2
27
3
26
4
25
5
24
6
23
7
8
GND
22
21
9
20
10
19
11
18
12
13
14
17
29
16
15
GND
GND
GND
GND
LED1
LED2
LED3
LED4
LED5
LED6
LED7
LED8
VCC
CREG
TSSOP-28 (Exposed Pad)
RT8566GCP : Product Number
RT8566
GCPYMDNN
YMDNN : Date Code
Copyright © 2013 Richtek Technology Corporation. All rights reserved.
DS8566-03
November 2013
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
1
RT8566
Typical Application Circuit
L1
10µH
VIN
9 to 28V
D1
CIN
47µF
CVCC
1µF
RSENSE
100m
RF2
0
RT8566
LED1
12
SEN
LED8
CF
1nF
PWM Signal
24
17
RSTATUS
100k
14 DRV
1k
RISET
4 PWM
RT
Chip Enable
:
:
: …… :
:
:
:
:
STATUS 6
RDRV
5
1k 11
EN
RC
560
COUT
4.7µF x 6
……
RF1
100
ROVP1
82k
……
MSW
ROVP2
3.6M
OVP/UVP 1
16 VCC
VOUT
45V
9
CC
0.22µF
2
RISET
4.53k
8
RRT 56k
SS 10
CREG
VC
PGND
13
15
VIN
FLT
CSS 0.1µF
CREG 1µF
GND
25, 26, 27, 28,
29 (Exposed Pad)
Figure 1. General Application
FLT
VIN
9 to 28V
L1
10µH
D1
CIN
47µF
CVCC
1µF
RSENSE
100m
RF2
0
RT8566
LED1
12
SEN
CF
1nF
Chip Enable
:
:
: …… :
:
:
:
:
24
17
RSTATUS
100k
STATUS 6
RDRV
5
PWM Signal
LED8
14 DRV
1k
4 PWM
1k 11
EN
RC
560
CC
0.22µF
9
VC
PGND
13
RISET
RT
RISET
4.53k
8
RRT 56k
15
VIN
FLT
2
SS 10
CREG
COUT
4.7µF x 6
……
RF1
100
ROVP1
82k
……
MSW
OVP/UVP 1
16 VCC
VOUT
45V
ROVP2
3.6M
CSS 0.1µF
CREG 1µF
GND
25, 26, 27, 28,
29 (Exposed Pad)
Figure 2. External P-MOSFET Isolation Application
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is a registered trademark of Richtek Technology Corporation.
DS8566-03
November 2013
RT8566
Functional Pin Description
Pin No.
Pin Name
Pin Function
NC
Over Voltage and Under Voltage Protection. PWM boost converter turns off when
VOVP or VUVP goes higher than 1.2V or lower than 0.6V, respectively.
LED Current Set Pin. A resistor or a current from DAC on this pin programs the
full LED current.
No Internal Connection.
4
PWM
Dimming Control Input.
6
STATUS
Boost Converter Operation Status Output.
8
RT
Switching Frequency Set. Connect a resistor between RT and GND to set the
boost converter switching frequency.
9
VC
10
SS
11
EN
12
SEN
13
PGND
14
DRV
15
CREG
16
VCC
1
OVP/UVP
2
RISET
3, 5, 7
17 to 24
LED8 to
LED1
25, 26, 27, 28
GND
29 (Exposed pad)
PWM Boost Converter Loop Compensation Node.
Soft-Start Pin. Place a capacitor of at least 10nF from this pin to GND to set the
soft-start time period.
Chip Enable. When EN is pulled low, chip will be in shutdown mode.
Current Sense Input. During normal operation, this pin senses the voltage across
the external inductor current sensing resistor for peak current mode control and
also to limit the inductor current during every switching cycle.
Boost Converter Power Ground.
Boost Converter Power Switch Gate Output. This pin drives the external power
N-MOSFET device.
1F capacitor should be placed on this pin to stabilize the 5V output of the
internal regulator. This regulator is for chip internal use only.
Power Supply of the Chip. For good bypass, a low ESR capacitor close to the pin
is required.
Channel 8 to Channel 1 LED Current Sink. Leave the pins unconnected if not
used.
Ground. The exposed pad must be soldered to a large PCB and connected to
GND for maximum power dissipation.
Copyright © 2013 Richtek Technology Corporation. All rights reserved.
DS8566-03
November 2013
is a registered trademark of Richtek Technology Corporation.
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RT8566
Function Block Diagram
DRV SEN
OSC
RT
VCC
STATUS
OVP
-
UVLO
UVP
OTP
S
+
R
OVP/UVP
+
-
0.6V
+
R
LED Short
LED1
UVP
+
-
EN
-
5V
LDO
VC
Shutdown
+
CREG
+
-
1.2V
…………………
1.2V
LED8
VOUT
Regulation
Unit
+
5V
-
6µA
SS
PWM
GND
PGND
+
-
RISET
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is a registered trademark of Richtek Technology Corporation.
DS8566-03
November 2013
RT8566
Absolute Maximum Ratings









(Note 1)
Supply Voltage, VCC , STATUS ----------------------------------------------------------------------------------------LED1 to LED8 --------------------------------------------------------------------------------------------------------------PWM, EN, DRV, SEN, SS, VC, RT, CREG, OVP/UVP, RISET ------------------------------------------------Power Dissipation, PD @ TA = 25°C
TSSOP-28 (Exposed Pad) ----------------------------------------------------------------------------------------------Package Thermal Resistance (Note 2)
TSSOP-28 (Exposed Pad), θJA -----------------------------------------------------------------------------------------TSSOP-28 (Exposed Pad), θJC ----------------------------------------------------------------------------------------Junction Temperature -----------------------------------------------------------------------------------------------------Lead Temperature (Soldering, 10 sec.) -------------------------------------------------------------------------------Storage Temperature Range --------------------------------------------------------------------------------------------ESD Susceptibility (Note 3)
HBM (Human Body Model) ----------------------------------------------------------------------------------------------MM (Machine Model) ------------------------------------------------------------------------------------------------------
Recommended Operating Conditions




33V
50V
5.5V
3.571W
28°C/W
7°C/W
150°C
260°C
−65°C to 150°C
2kV
200V
(Note 4)
Supply Voltage, VCC ------------------------------------------------------------------------------------------------------LED1 to LED8 --------------------------------------------------------------------------------------------------------------Junction Temperature Range --------------------------------------------------------------------------------------------Ambient Temperature Range ---------------------------------------------------------------------------------------------
9V to 28V
45V
−40°C to 125°C
−40°C to 85°C
Electrical Characteristics
(VCC = 12V, TA = 25°C, unless otherwise specified)
Parameter
Symbol
Test Conditions
Min
Typ
Max
Unit
Supply Voltage
Supply Current
IVCC
Switching Off
--
5
--
mA
Shutdown Current
ISHDN
VEN  0.7V
--
--
10
A
VDD LDO Output
VCREG
--
5
--
V
VDD LDO Capability
ICREG
30
--
--
mA
VCC UVLO Threshold
VUVLO
EN Input
Threshold Voltage
VCC Rising
--
--
8
Hysteresis
--
1.4
--
V
Logic-High
VENH
1.5
--
--
V
Logic-Low
VENL
--
--
0.8
V
114
120
126
mA
--
1.5
3
%
--
0.6
--
V
LED Current Programming
LED Current Accuracy
LED Current Matching
RISET = 4.53k, V PWM  1.2V
RISET = 4.53k, V PWM  1.2V
I(MAX)  I(MIN)
2  I(Avg)
LED1 to LED8 Regulation
Voltage
Copyright © 2013 Richtek Technology Corporation. All rights reserved.
DS8566-03
November 2013
 100%
ILED = 120mA
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®
RT8566
Parameter
Symbol
VLED Threshold
Test Conditions
No Connection
RISET Pin Voltage
Dimming
PWM Input
Threshold Voltage
Min
Typ
Max
Unit
--
0.1
--
V
--
1.2
--
V
Logic-High
VPW MH
1.2
--
--
Logic-Low
VPW ML
--
--
0.4
RRT = 24k
--
1
--
MHz
RRT = Open
--
100
--
kHz
V
PWM Boost Controller
Switching Frequency
fSW
Minimum On Time
tON
--
100
--
ns
Maximum Duty Cycle
Dmax
80
--
--
%
--
0.5
--
V
Gate Driver Source
--
2.5
--
A
Gate Driver Sink
--
3
--
A
SEN Current Sense Limit
Input Current Limit
OVP, UVP, SCP, OTP and Soft-Start
OVP Threshold
VOVP
1.1
1.2
1.3
V
UVP Threshold
VUVP
0.57
0.6
0.63
V
SCP Threshold
VSCP
LED1 to LED8
--
4.3
--
V
Soft-Start Current
ISS
VSS  2.5V
--
6
--
A
Thermal Shutdown Temperature
TSD
Lockout Temperature Point
--
150
--
C
Thermal Shutdown Hysteresis
TSD
Resume Temperature Point
--
20
--
C
STATUS Low Voltage
VSTATUS
Open Drain at 10mA
--
--
0.5
V
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. 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 3. Devices are ESD sensitive. Handling precaution is recommended.
Note 4. The device is not guaranteed to function outside its operating conditions.
Copyright © 2013 Richtek Technology Corporation. All rights reserved.
DS8566-03
November 2013
is a registered trademark of Richtek Technology Corporation.
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®
RT8566
Typical Operating Characteristics
LED Current vs. Input Voltage
LED Current vs. PWM Duty Cycle
120
100
140
LED Current (mA)
LED Current (mA)
160
120
LED1
LED2
LED3
LED4
LED5
LED6
LED7
LED8
100
80
80
PWM = 200Hz
PWM = 1kHz
PWM = 10kHz
60
40
20
96LEDs, RISET = 4.3kΩ
VIN = 12V, 96LEDs, RISET = 4.3kΩ
0
60
8
10
12
14
16
18
20
22
24
26
0
28
10
20
30
40
50
60
70
Input Voltage (V)
PWM Duty Cycle (%)
Efficiency vs. Input Voltage
Power On from VIN
80
90
100
100
Efficiency (%)
95
90
VIN
(5V/Div)
85
DRV
(5V/Div)
80
75
96LEDs, RISET = 4.3kΩ
70
8
10
12
14
16
18
20
22
24
26
I IN
(1A/Div)
VIN = 12V, CSS = 0.1μF,
96LEDs, RISET = 9.1kΩ
Time (5ms/Div)
28
Input Voltage (V)
Power On from EN
Power On from PWM
VEN
(2V/Div)
PWM
(2V/Div)
DRV
(5V/Div)
DRV
(5V/Div)
I IN
(1A/Div)
VIN = 12V, CSS = 0.1μF,
96LEDs, RISET = 9.1kΩ
Time (5ms/Div)
Copyright © 2013 Richtek Technology Corporation. All rights reserved.
DS8566-03
November 2013
I IN
(1A/Div)
VIN = 12V, CSS = 0.1μF,
96LEDs, RISET = 9.1kΩ
Time (5ms/Div)
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RT8566
Application information
The RT8566 is an 8-CH driver controller that delivers well
matched LED current to each channel of LED strings. The
external N-MOSFET current source will accommodate the
power dissipation difference among channels resulting from
the forward voltage difference between the LED strings.
With high speed current source N-MOSFET drivers, the
RT8566 features highly accurate current matching, while
also providing very fast turn-on and turn-off times. This
allows a very narrow minimum on or off pulse. The RT8566
integrates adjustable switching frequency and soft-start
and provides circuitry for over temperature, over voltage,
under voltage and current limit protection.
Soft-Start
The RT8566 employs a soft-start feature to limit the inrush
current. The soft-start circuit prevents excessive inrush
current and input voltage droop. The soft-start time is
determined by a capacitor, CSS, connected between SS
and GND and charged with a 6μA constant current as shown
in the following equation.
tSS (max) = CSS x 4.8 x 105 (s)
The value of capacitor CSS is user-defined to satisfy the
designer' requirement.
Compensation
Setting and Regulation of LED current
The LED current can be calculated by the following
equation :
543.6
ILED 
RISET
where RISET is the resistor between the RISET pin and
GND. This setting is the reference for the LED current at
pin LEDx and represents the sensed LED current for each
string. The DC/DC converter regulates the LED current
according to the setting.
Over Voltage and Under Voltage Protection
The RT8566 integrates Over Voltage Protection (OVP) and
Under Voltage Protection (UVP). When the voltage at the
OVP/UVP pin rises above the threshold voltage of
approximately 1.2V or falls below the threshold voltage of
approximately 0.6V, the internal switch will be turned off
and STATUS pin will be pulled high. The internal switch
will be turned on again once the voltage at the OVP/UVP
pin returns to normal range. The output voltage can be
clamped at a certain voltage level and can be calculated
by the following equations :


R
VOUT(OVP) = VOVP x  1 + OVP2 
R
OVP1 



R
VOUT(UVP) = VUVP x  1 + OVP2 
R
OVP1 

The regulator loop can be compensated by adjusting the
external components connected to the VC pin. The VC
pin is the output of the internal error amplifier. The
compensation capacitor will adjust the integrator zero to
maintain stability and the resistor value will adjust the
frequency integrator gain for fast transient response.
Typical values of the compensation components are RC =
560Ω, CC = 0.22μF.
where ROVP1 and ROVP2 are the resistors in the resistive
voltage divider connected to the OVP/UVP pin. If at least
one string is in normal operation, the controller will
automatically ignore the open strings and continue to
regulate the current for the strings in normal operation.
Suggested value for ROVP2 is up to 3MΩ to prevent loading
effect.
LED Connection
LED Short Circuit Protection
The RT8566 equips 8-CH LED drivers and each channel
supports up to 15 LEDs. The LED strings are connected
from the output of the boost converter to pin LEDx (x = 1
to 8) respectively. If one of the LED channel is not in use,
the LED pin should be opened directly.
The RT8566 integrates LED Short Circuit Protection (SCP).
If one of the LED1 to LED8 pin voltages exceeds a
threshold of approximately 4.3V during normal operation,
the STATUS pin will be pulled high for a fault signal.
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is a registered trademark of Richtek Technology Corporation.
DS8566-03
November 2013
RT8566
STATUS
Over Temperature Protection
After the IC is enable. STATUS will output logic high if
LED Short/OVP/UVP/OTP conditions exist. STATUS will
be reset after VIN or EN is re-applied.
The RT8566 has over temperature protection function to
prevent the IC from overheating due to excessive power
dissipation. The IC will shut down and the STATUS pin
will be pulled high when junction temperature exceeds
150°C. Main converter starts switching after junction
temperature cools down by approximately 20°C.
Setting the Switching Frequency
The RT8566 switching frequency is programmable from
100kHz to 1MHz by adjusting the oscillator resistor, RRT.
The switching frequency can be calculated by the following
equation :
21.6 x 109
fSW  100k +
RRT
Current Limit Protection
Brightness Control
The RT8566 features a digital dimming control scheme. A
very high contrast ratio true digital PWM dimming is
achieved by driving the PWM pin with a PWM signal. The
recommended PWM frequency is 200Hz to 10kHz, but
the LED current cannot be 100% proportional to duty cycle,
especially for high frequency and low duty ratio.
Table 1.
Dimming Frequency (Hz) Duty (Min.) Duty (Max.)
200 < f PWM  500
0.2%
100%
500 < fPWM  1k
0.4%
100%
1k < fPWM  2k
0.7%
100%
2k < fPWM  5k
1.4%
100%
5k < fPWM  10k
3.3%
100%
Note : The minimum duty in Table 1 is based on the application
circuit and does not consider the deviation of current linearity.
Copyright © 2013 Richtek Technology Corporation. All rights reserved.
November 2013
The value of the inductance, L, can be approximated by
the following equation, where the transition is from
Discontinuous Conduction Mode (DCM) to Continuous
Conduction Mode (CCM) :
2
The RT8566 can sense the RSENSE voltage between the
SEN pin and GND to achieve over current protection. The
boost converter senses the inductor current during the on
period. The duty cycle depends on the current signal and
internal slope compensation compared with the error
signal. The external switch will be turned off when the
current signal is larger than the internal slope
compensation. In the off period, the inductor current will
decrease until the internal switch is turned on by the
oscillator. The current limit value can be calculated by the
following equation :
0.5V
Current Limit (A) 
RSENSE
DS8566-03
Inductor Selection
L=
D x 1  D  x VOUT
2 x f x IOUT
The duty cycle can be calculated as the following
equation :
D=
VOUT  VIN
VOUT
where VOUT is the maximum output voltage, VIN is the
minimum input voltage, f is the operating frequency, and
IOUT is the sum of current from all LED strings.
The boost converter operates in DCM over the entire input
voltage range when the inductor value is less than this
value, L. With an inductance greater than L, the converter
operates in CCM at the minimum input voltage and may
be discontinuous at higher voltages.
The inductor must be selected with a saturated current
rating that is greater than the peak current as provided by
the following equation :
IPEAK =
VOUT x IIOUT VIN x D x T

η x VIN
2xL
where η is the efficiency of the power converter.
Diode Selection
Schottky diodes are recommended for most applications
because of their fast recovery time and low forward voltage.
Power dissipation, reverse voltage rating, and pulsating
peak current are important parameters for consideration
when making a Schottky diode selection. Make sure that
the diode's peak current rating exceeds IPEAK and reverse
voltage rating exceeds the maximum output voltage.
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RT8566
The input capacitor reduces current spikes from the input
supply and minimizes noise injection to the converter. For
general applications, six 4.7μF ceramic capacitors are
sufficient. A value higher or lower may be used depending
on the noise level from the input supply and the input
current to the converter.
The maximum power dissipation depends on the operating
ambient temperature for fixed T J(MAX) and thermal
resistance, θJA. For the RT8566 packages, the derating
curve in Figure 3 allows the designer to see the effect of
rising ambient temperature on the maximum power
dissipation.
4.0
Maximum Power Dissipation (W)
Capacitor Selection
It is recommended to choose a ceramic capacitor based
on the output voltage ripple requirements. The minimum
value of the output capacitor, COUT, can be calculated by
the following equation :
COUT =
IOUT x D
VOUT x f
where ΔVOUT is the peak-to-peak ripple voltage at the
output.
PD(MAX) = (TJ (MAX) − TA) / θJA
where TJ (MAX) is the maximum junction temperature, TA is
the ambient temperature, and θJAis the junction to ambient
thermal resistance.
For recommended operating condition specifications of
the RT8566, the maximum junction temperature is 125°C
and TA is the ambient temperature. The junction to ambient
thermal resistance, θJA, is layout dependent. For TSSOP28 (Exposed Pad) packages, the thermal resistance, θJA,
is 28°C/W on a standard JEDEC 51-7 four-layer thermal
test board. The maximum power dissipation at TA = 25°C
can be calculated by the following formula :
3.2
2.8
2.4
2.0
1.6
1.2
0.8
0.4
0.0
Thermal Considerations
For continuous operation, do not exceed absolute
maximum junction temperature. The maximum power
dissipation depends on the thermal resistance of the IC
package, PCB layout, rate of surrounding airflow, and
difference between junction and ambient temperature. The
maximum power dissipation can be calculated by the
following formula :
Four-Layer PCB
3.6
0
25
50
75
100
125
Ambient Temperature (°C)
Figure 3. Derating Curve for RT8566 Packages
Layout Considerations
Careful PCB layout is very important for designing
switching power converter circuits. The following layout
guidelines should be strictly followed for best performance
of the RT8566.

The power components L1, D1, CIN, COUT must be placed
as close as possible to the IC to reduce current loop.
The PCB trace between power components must be as
short and wide as possible.

The compensation circuit should be kept away from
the power loops and shielded with a ground trace to
prevent any noise coupling. Place the compensation
components, RC and CC, as close as possible to pin 9.

The exposed pad of the chip should be connected to
ground plane for thermal consideration.
PD(MAX) = (125°C − 25°C / (28°C/W) = 3.571W for
TSSOP-28 (Exposed Pad) package
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is a registered trademark of Richtek Technology Corporation.
DS8566-03
November 2013
RT8566
OVP/UVP
The compensation
RISET
circuit should be kept
NC
away from the power
PWM
loops and shielded
NC
with a ground trace
to prevent any noise STATUS
NC
coupling.
RT
VC
SS
GND CC RC
EN
SEN
PGND
VOUT
DRV
D1
27
3
26
4
25
5
24
6
23
7
8
22
GND
21
9
20
10
19
11
18
17
12
29
13
16
15
14
L1
COUT
RDRV
VIN
CIN
VIN
RF1
CF
GND
+
MSW
RF2
GND
GND
GND
GND
LED1
LED2
LED3
LED4
LED5
LED6
LED7 Locate CVCC as close
LED8 to VCC as possible.
VCC
CREG
CVCC
28
2
RSENSE
PGND
Place the power
components as close as
possible to the IC. The
traces should be wide
and short especially for
the high-current loop.
Figure 4. PCB Layout Guide
Copyright © 2013 Richtek Technology Corporation. All rights reserved.
DS8566-03
November 2013
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
11
RT8566
Outline Dimension
Dimensions In Millimeters
Sym bol
Dimensions In Inches
Min
Max
Min
Max
A
1.000
1.200
0.039
0.047
A1
0.000
0.150
0.000
0.006
A2
0.800
1.050
0.031
0.041
b
0.190
0.300
0.007
0.012
D
9.600
9.800
0.378
0.386
e
0.650
0.026
E
6.300
6.500
0.248
0.256
E1
4.300
4.500
0.169
0.177
L
0.450
0.750
0.018
0.030
U
4.410
5.510
0.174
0.217
V
2.400
3.000
0.094
0.118
U
5.500
6.170
0.217
0.243
V
1.600
2.210
0.063
0.087
Option 1
Option 2
28-Lead TSSOP (Exposed Pad) Plastic Package
Richtek Technology Corporation
14F, No. 8, Tai Yuen 1st Street, Chupei City
Hsinchu, Taiwan, R.O.C.
Tel: (8863)5526789
Richtek products are sold by description only. Richtek reserves the right to change the circuitry and/or specifications without notice at any time. Customers should
obtain the latest relevant information and data sheets before placing orders and should verify that such information is current and complete. Richtek cannot
assume responsibility for use of any circuitry other than circuitry entirely embodied in a Richtek product. Information furnished by Richtek is believed to be
accurate and reliable. However, no responsibility is assumed by Richtek or its subsidiaries for its use; nor for any infringements of patents or other rights of third
parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Richtek or its subsidiaries.
www.richtek.com
12
DS8566-03
November 2013