DS8450B 05

®
RT8450/B
High Voltage Multi-Topology LED Driver
General Description
Features
The RT8450/B is a current mode PWM regulator for LED
driving applications. With an 1.5A switch on board and
wide input (4.5V to 40V) and/or output (up to 50V)ranges
the RT8450/B can operate in any of the three common
topologies : Buck, Boost or Buck-Boost.

High Voltage : VIN Up to 40V, VOUT Up to 50V

1.5A Switch Current
Buck, Boost or Buck-Boost Operation
Current Mode PWM with 800kHz (RT8450) and
500kHz (RT8450B) Switching Frenquency
Easy Dimming : Analog, PWM Digital or PWM
Converting to Analog with One External Capacitor
Programmable Soft-Start to Avoid Inrush Current
Programmable Over Voltage Protection to Limit
Output Voltage
VIN Under Voltage Lockout and Thermal Shutdown
RoHS Compliant and Halogen Free
With 800k/500kHz operating frequency, the external PWM
inductor and input/output capacitors can all be small. High
efficiency is achieved by a 190mV current sensing.





Dimming can be done either analog or PWM signal. An
unique built-in clampping comparator and filtering resistor
allow easy low noise analog dimming conversion from
PWM signal with only one external capacitor.
The RT8450/B is available in a TSSOP-16 (Exposed Pad)
and WDFN-12L 3x3 packages.
Ordering Information
RT8450/B
Package Type
CP : TSSOP-16 (Exposed Pad)
QW : WDFN-12L 3x3 (W-Type)
(Exposed Pad-Option 1)
Lead Plating System
G : Green (Halogen Free and Pb Free)
Switching Frequency
500kHz
800kHz
Note :
Richtek products are :


Applications



GPS, Portable DVD Backlight
Desk Lights and Room Lighting
Industrial Display Backlight
Pin Configurations
(TOP VIEW)
ISP
ISN
VC
ACTL
DCTL
EN
OVP
SS
2
3
4
5
6
7
8
16
15
14
13
GND
12
17 11
10
9
VCC1
VCC2
SW
SW
GND
GND
GND
GND
TSSOP-16 (Exposed Pad)
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
For marking information, contact our sales representative
directly or through a Richtek distributor located in your
area.
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DS8450/B-05 August 2014
ISP
ISN
VC
ACTL
DCTL
EN
1
2
3
4
5
6
GND
13
12
11
10
9
8
7
VCC2
VCC1
SW
GND
SS
OVP
WDFN-12L 3x3
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RT8450/B
Typical Application Circuit
VIN
4.5V to 40V
C1
RT8450/B
5V
VCCx
ISP
EN
ISN
R3
R4
DCTL
PWM
Dimming control
OVP
VC
R1
10k
ACTL
C3
10nF
C5
GND
SS
C2
3.3nF
R2
190mV
SW
L
20µH
C4
0.47µF
Figure 1. PWM to Analog Dimming Buck Configuration
VIN
4.5V to 40V
C1
RT8450/B
Analog
Dimming
VCCx
ISP
ACTL
ISN
R2
190mV
R3
R4
DCTL
OVP
EN
5V
GND
VC
R1
10k
C2
3.3nF
C4
L
15µH
SS
SW
C3
10nF
Figure 2. Analog Dimming Buck Configuration
VIN
4.5V to 40V
C1
RT8450/B
PWM
Dimming control
5V
VCCx
ISP
ACTL
ISN
DCTL
OVP
EN
GND
VC
R1
10k
C2
3.3nF
R3
R4
C4
L
15µH
SS
C3
10nF
R2
190mV
SW
Figure 3. PWM Dimming Buck Configuration Through ACTL Pin
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DS8450/B-05 August 2014
RT8450/B
L
15µH
VIN
4.5V to 40V
C1
C5
1µF
RT8450/B
5V
PWM
Dimming control
VCCx
SW
EN
ISP
DCTL
ISN
R2
190mV
VC
R1
10k
C2
3.3nF
SS
ACTL
C3
10nF
R3
OVP
GND
VOUT
R4
C4
0.47µF
Figure 4. PWM to Analog Dimming Boost Configuration
C5
L
VIN
4.5V to 40V
VOUT
15µH
C1
RT8450/B
VCCx
5V
PWM
Dimming control
SW
EN
ISP
DCTL
ISN
R2
190mV
VC
R1
10k
C2
3.3nF
C3
10nF
SS
OVP
ACTL
GND
R3
VOUT
R4
C4
0.47µF
Figure 5. PWM to Analog Dimming Buck-Boost Configuration
Functional Pin Description
Pin No.
Pin Name
Pin Function
TSSOP-16
WDFN-12L 3x3
(Exposed Pad)
1
1
ISP
Current Sense Amplifier Positive Input.
Current Sense Amplifier Negative Input. Voltage threshold between
2
2
ISN
ISP and ISN is 190mV.
PWM Boost Converter Loop Compensation Node.
3
3
VC
Analog Dimming Control. Effective programming range is between
4
4
ACTL
0.3V and 1.2V.
By Adding a 0.47F Filtering Capacitor on ACTL Pin, the PWM
dimming signal on DCTL pin will be averaged and converted into
5
5
DCTL
analog dimming signal on ACTL pin. VACTL = 1.2V x PWM dimming
duty cycle .
6
6
EN
Chip Enable (Active High), when low chip is in shutdown mode.
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RT8450/B
Pin No.
Pin Name
TSSOP-16
(Exposed Pad)
WDFN-12L 3x3
7
7
OVP
8
8
SS
9, 10, 11, 12,
9,
17 (Exposed Pad) 13 (Exposed Pad)
13, 14
GND
10
SW
Pin Function
Over voltage protection. PWM boost converter turns off when
VOVP goes higher than 1.2V.
Soft-Start Pin, a capacitor of at least 10nF is required for softstart.
Ground. The exposed pad must be soldered to a large PCB
and connected to GND for maximum power dissipation.
PWM Boost Converter Switch Node.
15
12
VCC2
Bipolar Power Switch Base Current Supply. VCC2 can be
connected either to VCC1 or to a separate lower voltage, as
low as 3V, for better system efficiency and/or heat concern. A
good bypass is necessary.
16
11
VCC1
Power Supply of the Chip. For good bypass, a low ESR
capacitor is required.
Function Block Diagram
SW
VCC1
OSC
-
4.5V
VCC2
S
+
R
OVP
+
1.2V
R
-
EN
+
Shutdown
-
+
-
1.4V
VC
ISN
ISP
GM
+
6µA
SS
1.2V
DCTL
+
+
-
-
GND
ACTL
VISP – VISN
(mV)
190
0
0.3
1.2
VACTL (V)
Figure 6
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DS8450/B-05 August 2014
RT8450/B
Absolute Maximum Ratings










(Note 1)
Supply Input Voltage, VCC1, VCC2 ---------------------------------------------------------------------------------------- 45V
SW Pin Voltage at Switching Off, ISP, ISN ---------------------------------------------------------------------------- 55V
DCTL, ACTL, OVP Pin Voltage ------------------------------------------------------------------------------------------ 8V (Note 2)
EN Pin Voltage --------------------------------------------------------------------------------------------------------------- 20V
Power Dissipation, PD @ TA = 25°C
TSSOP-16 --------------------------------------------------------------------------------------------------------------------- 2.66W
WDFN-12L 3x3 --------------------------------------------------------------------------------------------------------------- 1.667W
Package Thermal Resistance (Note 3)
TSSOP-16, θJA --------------------------------------------------------------------------------------------------------------- 47°C/W
WDFN-12L 3x3, θJA --------------------------------------------------------------------------------------------------------- 60°C/W
WDFN-12L 3x3, θJC --------------------------------------------------------------------------------------------------------- 8.2°C/W
Junction Temperature ------------------------------------------------------------------------------------------------------- 150°C
Lead Temperature (Soldering, 10 sec.) --------------------------------------------------------------------------------- 260°C
Storage Temperature Range ---------------------------------------------------------------------------------------------- −65°C to 150°C
ESD Susceptibility (Note 4)
HBM (Human Body Mode) ------------------------------------------------------------------------------------------------ 2kV
MM (Machine Mode) -------------------------------------------------------------------------------------------------------- 200V
Recommended Operating Conditions


(Note 5)
Junction Temperature Range ---------------------------------------------------------------------------------------------- −40°C to 125°C
Ambient Temperature Range ---------------------------------------------------------------------------------------------- −40°C to 85°C
Electrical Characteristics
(VCC1 = VCC2 = 12V, No Load on any Output, TA = 25°C, unless otherwise specified)
Parameter
Symbol
Test Conditions
Min
Typ
Max
Unit
Overall
Supply Voltage
VCC1
4.5
--
40
V
Supply Voltage VCC2 for Switch
Base Drive
VCC2
3
--
40
V
Supply Current
IVCC1
VC  0.4V (Switching off)
--
4
6
mA
Supply Current
IVCC2
VCC1 = VCC2 = 24V, I SW  1A
--
Shutdown Current
ISHDN_VCC1 VEN  0.7V
--
12
--
A
Shutdown Threshold
VEN
1
1.4
--
V
--
--
0.5
A
170
190
210
mV
EN Input Current
VEN = 3V
ISW/70 ISW/40
A
Current Sense Amplifier
Input Threshold (VISP  VISN)
4.5V  common mode  50V
Input Current
IISP
VISP = 24V
--
100
--
A
Input Current
IISN
VISN = 24V
--
40
--
A
Output Current
IVC
2.4V > VC > 0.2V
--
20
--
A
--
0.7
--
V
VC Threshold for PWM Switch Off
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RT8450/B
Parameter
Symbol
Test Conditions
Min
Typ
Max
Unit
--
--
3
A
--
0.2
--
V
--
--
0.5
A
RT8450
600
800
1000
kHz
RT8450B
RT8450
400
--
500
80
600
--
kHz
RT8450B
--
86
--
--
250
--
ns
--
0.4
--
V
1.25
1.5
--
A
--
1.2
--
V
LED Dimming
Analog Dimming ACTL Pin
Input Current
LED Current Off Threshold at
ACTL
DCTL Input Current
IACTL
0.3V  VACTL  1.2V
VACTL
IDCTL
0.3V  VDCTL  6V
PWM BOOST Converter
Switching Frequency
Maximum Duty Cycle
(Note 6)
fSW
DMAX
Minimum on Time
SW On-Voltage
VSW
SW Current Limit
ILIM_SW
ISW = 0.5A
%
OVP and Soft Start
OVP Threshold
VOVP
OVP Input Current
IOVP
0.7V  VOVP  1.5V
--
--
0.5
A
Soft Start SS Pin Current
ISS
VSS  2V
--
6
--
A
Note 1. Stresses beyond those listed under “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 for extended periods 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 in the natural convection at TA = 25°C on a high effective four layers thermal conductivity test board of
JEDEC 51-7 thermal measurement standard.
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. When the natural maximum duty cycle of the switching frequency is reached, the switching cycle will be skipped (not
reset) as the operating condition requires to effectively stretch and achieve higher on cycle than the natural maximum
duty cycle set by the switching frequency.
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RT8450/B
Typical Operating Characteristics
(ISP – ISN) Voltage vs ACTL Input Voltage
200
198
180
(ISP – ISN) Voltage (mV)
(ISP – ISN) Voltage (mV)
(ISP – ISN) Voltage vs. Input Voltage
200
196
194
192
190
188
186
184
182
4
8
12
16
20
24
28
32
36
140
120
100
80
60
40
20
VIN = 24V, VACTL = 1.5V
180
160
VIN = 24V
0
40
0.2
0.5
Input Voltage (V)
Supply Current vs. Input Voltage
1.4
100
4.5
95
4
90
3.5
Efficiency (%)
Supply Current (mA)
1.1
Efficiency vs. Input Voltage
5
3
2.5
2
1.5
85
80
75
70
1
65
0.5
VIN = 24V, VACTL = 0V
Buck, VOUT = 21V, ILED = 350mA
0
60
4
8
12
16
20
24
28
32
36
40
22
24
26
Input Voltage (V)
28
30
32
34
36
38
40
Input Voltage (V)
Efficiency vs. Input Voltage
Efficiency vs. Input Voltage
100
100
90
90
80
80
70
70
Efficiency (%)
Efficiency (%)
0.8
ACTL Input Voltage (V)
60
50
40
30
20
60
50
40
30
20
10
Boost, VOUT = 21V, ILED = 350mA
0
6
8
10
12
14
16
18
Input Voltage (V)
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20
10
Buck~Boost, VOUT = 10.5V, ILED = 350mA
0
6
8
10
12
14
16
18
Input Voltage (V)
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RT8450/B
LED Current vs. ACTL
600
500
500
LED Current (mA)
LED Current (mA)
LED Current vs. DCTL Duty
600
400
300
200
100
0
10
20
30
40
50
60
70
80
90
300
200
100
VIN = 24V, f = 1kHz
VDCTL = 0V to 3V, R2 = 0.35Ω
0
400
VIN = 24V, R2 = 0.35Ω
0
0.2
100
0.4
0.6
DCTL Duty (%)
1
1.2
1.4
ACTL (V)
OVP vs. Input Voltage
OVP vs. Temperature
1.23
1.220
1.22
OVP (V)
1.215
OVP (V)
0.8
1.210
1.205
1.21
1.2
1.19
VIN = 24V
1.200
1.18
4
10
16
22
28
34
40
-50
-25
0
25
50
75
100
125
Temperature (°C)
Input Voltage (V)
Current Limit vs. Input Voltage
ACTL-Off vs. Temperature
1.60
0.2000
0.1975
Current Limit (A)
ACTL-Off (V)
0.1950
0.1925
0.1900
0.1875
1.55
1.50
1.45
0.1850
0.1825
VIN = 24V
0.1800
-50
-25
0
25
50
75
100
Temperature (°C)
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125
1.40
4
10
16
22
28
34
40
Input Voltage (V)
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RT8450/B
Switching Frequency vs. Input Voltage
SS pin Current vs. Temperature
10
9
RT8450
800
700
600
RT8450B
500
Soft Start Current (uA)
Switching Frequency (kHz)1
900
8
7
6
5
4
3
2
1
400
VIN = 12V, CSS= 0.1μF
0
4
10
16
22
28
34
40
-50
0
25
50
75
100
Power On from EN
Power On from EN
VIN
(10V/Div)
VEN
(5V/Div)
VIN
(20V/Div)
VEN
(5V/Div)
VOUT
(10V/Div)
IOUT
(100mA/Div)
VOUT
(10V/Div)
IOUT
(100mA/Div)
VIN = 24V
CSS = 0.1μF, 12 LEDs Boost
Time (250μs/Div)
Time (250μs/Div)
Line Transient Response
Line Transient Response
VIN
(10V/Div)
VIN
(10V/Div)
VOUT_ac
(20V/Div)
VOUT_ac
(20V/Div)
VIN = 12V to 15V
10 LEDs Boost
RISET = 0.68Ω
IOUT
(100mA/Div)
Time 1ms/Div)
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125
Temperature (°C)
Input Voltage (V)
VIN = 14V
CSS = 0.1μF, 10 LEDs Boost
-25
VIN = 20V to 24V
12 LEDs Boost
RISET = 0.68Ω
IOUT
(100mA/Div)
Time 1ms/Div)
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RT8450/B
Line Transient Response
VIN
(10V/Div)
VOUT_ac
(20V/Div)
VIN = 21V to 24V
6 LEDs Buck
RISET = 0.25Ω
IOUT
(100mA/Div)
Time 1ms/Div)
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DS8450/B-05 August 2014
RT8450/B
Application Information
The RT8450/B is specifically designed to be operated in
buck, buck -boost and boost converter applications. This
device uses a fixed frequency, current mode control
scheme to provide excellent line and load regulation. 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 protection schemes in the RT8450/B include over
temperature, input voltage under voltage, output voltage
over-voltage, and switch current limit.
Loop Compensation
The RT8450/B has an external compensation pin (VC)
allowing the loop response optimized for specific
application. An external resistor in series with a capacitor
is connected from the VC pin to GND to provide a pole
and a zero for proper loop compensation. The
recommended compensation resistance and capacitance
for the RT8450/B are 10k and 3.3nF.
Soft-Start
The soft-start of the RT8450/B can be achieved by
connecting a capacitor from the SS pin to GND. The builtin soft-start circuit reduces the start-up current spike and
output voltage overshoot. The soft-start time is determined
by the external capacitor charged by an internal 6μA
constant charging current. The SS pin directly limits the
rate of voltage rise on the VC pin, which in turn limits the
peak switch current. The value of the soft-start capacitor
is user-defined to satisfy the designer’ s requirement.
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DS8450/B-05 August 2014
LED Current Setting
The LED current could be calculated by the following
equation :
ILED,MAX =
V(ISP-ISN)
R2
Where V(ISP-ISN) is the voltage between ISP and ISN
(190mV typ. if ACTL or DCTL dimming is not applied) and
the R2 is the resister between ISP and ISN.
Brightness / Dimming Control
The RT8450/B features both analog and digital dimming
control. Analog dimming is linearly controlled by an
external voltage (0.3V < VACTL < 1.2V). With an on-chip
output clamping amplifier and a resistor, PWM dimming
signal fed at DCTL pin can be easily low-pass filtered to
an analog dimming signal with one external capacitor from
ACTL pin to GND for noise-free PWM dimming. A very
high contrast ratio true digital PWM dimming can be
achieved by driving ACTL pin with a PWM signal from
100Hz to 10kHz.
Output Over Voltage Setting
The RT8450/B is equipped with over voltage protection
(OVP) function. When the voltage at OVP pin exceeds a
threshold of approximately1.2V, the power switch is turned
off. The power switch can be turned on again once the
voltage at OVP pin drops below 1.2V.
For the Boost Application, the output voltage could be
clamped at a certain voltage level. The OVP voltage can
be set by the following equation :
R3
VOUT,OVP = 1.2 x (1 +
)
R4
Where R3 and R4 are the voltage divider from VOUT to
GND with the divider center node connected to OVP pin.
Current-Limit Protection
The RT8450/B can limit the peak switch current by the
internal over current protection feature. In normal operation,
the power switch is turned off when the switch current
hits the loop-set value. The over current protection function
will turn off the power switch independent of the loop control
when the peak switch current reaches around 1.5A.
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RT8450/B
Over Temperature Protection
Schottky Diode Selection
The RT8450/B has over temperature protection (OTP)
function to prevent the excessive power dissipation from
overheating. The OTP function will shut down switching
operation when the die junction temperature exceeds
150°C. The chip will automatically start to switch again
when the die junction temperature cools off.
The Schottky diode, with low forward voltage drop and
fast switching speed, is necessary for the RT8450/B
applications. In addition, power dissipation, reverse voltage
rating and pulsating peak current are the important
parameters of the Schottky diode that must be considered.
Choose a suitable Schottky diode whose reverse voltage
rating is greater than the maximum output voltage. The
diode’ s average current rating must exceed the average
output current. The diode conducts current only when the
power switch is turned off (typically less than 50% duty
cycle).
Inductor Selection
Choose an inductor that can handle the necessary peak
current without saturating, and ensure that the inductor
has a low DCR (copper-wire resistance) to minimize I2R
power losses. A 4.7μH to 10μH inductor will meet the
demand for most of the RT8450/B applications. Inductor
manufacturers specify the maximum current rating as the
current where the inductance falls to certain percentage
of its nominal value typically 65%.
In Boost application where the transition between
discontinuous and continuous modes occurs, the value
of the required output inductor (L), can be approximated
by the following equation :
V
x D x (1-D)2
L = OUT
2 x IOUT x f
The Duty Cycle (D) could be calculated as follows :
V
- VIN
D = OUT
VOUT
Where VOUT = maximum output voltage.
VIN = minimum input voltage.
f = operating frequency.
IOUT = sum of current from all LED strings.
The boost converter operates in discontinuous mode over
the entire input voltage range can have inductor value L1
less than the calculated value L by the formula above.
With an inductance value L2 greater than L, the converter
will operate in continuous mode at the minimum input
voltage and maybe operate in discontinuous mode at
higher voltages.
The inductor must be selected with a saturation current
rating greater than the peak current provided by the
following equation :
V
xI
V xDxT
IPEAK = OUT LED + IN
η x VIN
2xL
Where ç is the efficiency of the power converter.
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Capacitor Selection
The input capacitor reduces current spikes from the input
supply and minimizes noise injection to the converter. For
most RT8450/B applications, a 4.7μF ceramic capacitor
is 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.
In Boost Application, the output capacitor is typically a
ceramic capacitor and is selected based on the output
voltage ripple requirements. The minimum value of the
output capacitor COUT is approximately given by the
following equation :
I
xDxT
COUT = LED
VRIPPLE
Layout Consideration
PCB layout is very important to design power switching
converter circuits. Some recommended layout guidelines
are suggested as follows:

The power components L1, D1, CVIN, and COUT must be
placed as close to each other as possible to reduce the
ac current loop area. The PCB trace between power
components must be as short and wide as possible
due to large current flow through these traces during
operation.

Place L1 and D1 connected to SW pin as close as
possible. The trace should be as short and wide as
possible.

The input capacitors CVCC1 and CVCC2 must be placed
as close to VCC1 and VCC2 pin as possible.
is a registered trademark of Richtek Technology Corporation.
DS8450/B-05 August 2014
RT8450/B

Place the compensation components to the VC pin as
close as possible to avoid noise pick up.
Place these components as close as possible
L1
COUT
GND
GND
CVCC2
RSENS
:
:
:
:
RVC
CVC
VIN
ISP
1
12
VCC2
ISN
2
11
VCC1
VC
3
10
SW
ACTL
4
9
GND
5
8
SS
7
OVP
DCTL
EN
6
GND
Grand Plane
CVIN
CVCC1
GND
Locate input
capacitor as
close VCC as
possible.
CSS
GND
Locate the compensation components to VC
pin as close as possible.
Figure 7. PCB Layout Guide
Copyright © 2014 Richtek Technology Corporation. All rights reserved.
DS8450/B-05 August 2014
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
13
RT8450/B
Outline Dimension
D
L
U
EXPOSED THERMAL PAD
(Bottom of Package)
E
V
E1
e
A2
A
A1
b
Dimensions In Millimeters
Dimensions In Inches
Symbol
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
4.900
5.100
0.193
0.201
e
0.65
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
2.000
3.000
0.079
0.118
V
2.000
3.000
0.079
0.118
16-Lead TSSOP (Exposed Pad) Plastic Package
Copyright © 2014 Richtek Technology Corporation. All rights reserved.
www.richtek.com
14
is a registered trademark of Richtek Technology Corporation.
DS8450/B-05 August 2014
RT8450/B
2
1
2
1
DETAIL A
Pin #1 ID and Tie Bar Mark Options
Note : The configuration of the Pin #1 identifier is optional,
but must be located within the zone indicated.
Symbol
D2
Dimensions In Millimeters
Min.
Max.
Min.
Max.
A
0.700
0.800
0.028
0.031
A1
0.000
0.050
0.000
0.002
A3
0.175
0.250
0.007
0.010
b
0.150
0.250
0.006
0.010
D
2.950
3.050
0.116
0.120
Option1
2.300
2.650
0.091
0.104
Option2
1.970
2.070
0.078
0.081
2.950
3.050
0.116
0.120
Option1
1.400
1.750
0.055
0.069
Option2
1.160
1.260
0.046
0.050
E
E2
Dimensions In Inches
e
L
0.450
0.350
0.018
0.450
0.014
0.018
W-Type 12L DFN 3x3 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.
DS8450/B-05 August 2014
www.richtek.com
15