®
RT8286
2A, 21V 500kHz Synchronous Step-Down Converter
General Description
Features
The RT8286 is a synchronous step-down regulator with
integrated power MOSFETs. It achieves 2A of continuous
output current over a wide input supply range with excellent
load and line regulation. Current mode operation provides
fast transient response and eases loop stabilization.
z
2A Output Current
The RT8286 is available in a small SOP-8 (Exposed Pad)
package for a compact solution.
Internal Soft-Start
z 150mΩ
Ω/60mΩ
Ω Internal Power MOSFET Switch
z Internal Compensation Minimizes External Parts
Count
z Fixed 500kHz Frequency
z Thermal Shutdown Protection
z Cycle-by-Cycle Over Current Protection
z Wide 4.5V to 21V Operating Input Range
z Adjustable Output from 0.808V to 15V
z Available in an SOP-8 (Exposed Pad) Package
z RoHS Compliant and Halogen Free
Ordering Information
Applications
Fault condition protection includes cycle-by-cycle current
limiting and thermal shutdown. An internal soft-start
minimizes external parts count and internal compensation
circuitry.
RT8286
Package Type
SP : SOP-8 (Exposed Pad-Option 2)
z
z
z
z
Lead Plating System
Z : ECO (Ecological Element with
Halogen Free and Pb free)
z
Distributive Power Systems
Battery Charger
DSL Modems
Pre-Regulator for Linear Regulators
Pin Configurations
Note :
Richtek products are :
`
ments of IPC/JEDEC J-STD-020.
`
(TOP VIEW)
RoHS compliant and compatible with the current requireSuitable for use in SnPb or Pb-free soldering processes.
Marking Information
VIN
8
SW
2
SW
3
BOOT
4
GND
GND
7
VCC
6
FB
5
EN
9
SOP-8 (Exposed Pad)
RT8286ZSP : Product Number
RT8286
ZSPYMDNN
YMDNN : Date Code
Copyright © 2012 Richtek Technology Corporation. All rights reserved.
DS8286-02
June 2012
is a registered trademark of Richtek Technology Corporation.
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1
RT8286
Typical Application Circuit
1
VIN
CIN
22µF
Chip Enable
BOOT
VIN
4
RT8286
SW
5 EN
8, 9 (Exposed Pad)
GND
2, 3
CBOOT
100nF
L
VOUT
6
FB
RT
VCC 7
R2
R1
COUT
CC
0.1µF
Table 1. Recommended Components Selection
VOUT (V)
5
3.3
2.5
1.8
1.5
1.2
1.05
R1 (kΩ)
75
75
75
5
5
5
5
R2 (kΩ)
14.46
24.32
35.82
4.07
5.84
10.31
16.69
RT (kΩ)
0
0
0
30
39
47
47
L (μH)
4.7
3.6
3.6
2
2
2
1.5
COUT (μF)
22 x 2
22 x 2
22 x 2
22 x 2
22 x 2
22 x 2
22 x 2
Functional Pin Description
Pin No.
Pin Name
1
VIN
2, 3
SW
4
BOOT
5
EN
6
FB
7
VCC
8,
GND
9 (Exposed Pad)
Pin Function
Supply Input. VIN supplies the power to the IC, as well as the step-down converter
switches. Drive VIN with a 4.5V to 21V power source. Bypass VIN to GND with a
suitably large capacitor to eliminate noise on the input to the IC.
Switch Node. SW is the switching node that supplies power to the output. Connect
the output LC filter from SW to the output load. Note that a capacitor is required
from SW to BOOT to power the high side switch.
High Side Gate Drive Boost Input. BOOT supplies the drive for the high side
N-MOSFET switch. Connect a 100nF or greater capacitor from SW to BOOT to
power the high side switch.
Chip Enable (Active High). For automatic start up, connect the EN pin to VIN with
a 100kΩ resistor.
Feedback Input. FB senses the output voltage to regulate said voltage. Drive FB
with a resistive voltage divider from the output voltage. The feedback threshold is
0.808V.
Bias Supply. Decouple with 0.1μF to 0.22μF capacitor. The capacitance should be
no more than 0.22μF.
Ground. The Exposed Pad must be soldered to a large PCB and connected to
GND for maximum power dissipation.
Copyright © 2012 Richtek Technology Corporation. All rights reserved.
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is a registered trademark of Richtek Technology Corporation.
DS8286-02
June 2012
RT8286
Function Block Diagram
VIN
1.2V
Shutdown
Comparator
+
-
5k
1µA
3V
+
Regulator
BOOT
-
EN
Current Sense
Amplifier
-
Ramp
Generator
Oscillator
500kHz
+
Lockout
Comparator
S
Q
+
1.7V
PWM
Comparator
VCC
Reference
FB
Error
+ Amplifier
Driver
R
SW
GND
-
30pF
400k
1pF
Copyright © 2012 Richtek Technology Corporation. All rights reserved.
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June 2012
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3
RT8286
Absolute Maximum Ratings
z
z
z
z
z
z
z
z
z
z
(Note 1)
Supply Voltage, VIN ------------------------------------------------------------------------------------------- −0.3V to 26V
Switch Voltage, SW ------------------------------------------------------------------------------------------- −0.3V to (VIN + 0.3V)
Boot Voltage, BOOT ------------------------------------------------------------------------------------------- (SW − 0.3V) to (SW + 6V)
Other Pins -------------------------------------------------------------------------------------------------------- −0.3V to 6V
Power Dissipation, PD @ TA = 25°C
SOP-8 (Exposed Pad) ---------------------------------------------------------------------------------------- 1.333W
Package Thermal Resistance (Note 2)
SOP-8 (Exposed Pad), θJA ----------------------------------------------------------------------------------- 75°C/W
SOP-8 (Exposed Pad), θJC ---------------------------------------------------------------------------------------------------------------------- 15°C/W
Junction Temperature ------------------------------------------------------------------------------------------ 150°C
Lead Temperature (Soldering, 10 sec.) -------------------------------------------------------------------- 260°C
Storage Temperature Range --------------------------------------------------------------------------------- −65°C to 150°C
ESD Susceptibility (Note 3)
HBM (Human Body Model) ----------------------------------------------------------------------------------- 2kV
Recommended Operating Conditions
z
z
z
(Note 4)
Supply Input Voltage Range, VIN --------------------------------------------------------------------------- 4.5V to 21V
Junction Temperature Range --------------------------------------------------------------------------------- −40°C to 125°C
Ambient Temperature Range --------------------------------------------------------------------------------- −40°C to 85°C
Electrical Characteristics
(VIN = 5V, TA = 25°C, unless otherwise specified)
Parameter
Shutdown Current
Quiescent Current
Min
---
Typ
0
0.7
Max
1
--
Unit
μA
mA
ISHDN
IQ
Upper Switch On Resistance
R DS(ON)1
--
150
--
mΩ
Lower Switch On Resistance
R DS(ON)2
--
60
--
mΩ
Switch Leakage
Current Limit
ILEAK
ILIM
V EN = 0V, VSW = 0V or 12V
V BOOT − VSW = 4.8V
-3.9
0
5
10
--
μA
A
Oscillator Frequency
Short Circuit Frequency
f SW
V FB = 0.75V
V FB = 0V
425
--
500
150
575
--
kHz
kHz
Maximum Duty Cycle
D MAX
V FB = 0.8V
--
90
--
%
Minimum On Time
tON
--
100
--
ns
Feedback Voltage
V FB
0.796
0.808
0.82
V
nA
Feedback Current
EN Input Threshold
Voltage
Symbol
4.5V ≤ VIN ≤ 21V
Logic-High
IFB
V IH
-2
10
--
50
5.5
Logic-Low
V IL
V EN = 2V
---
-1
0.4
--
V EN = 0V
--
0
--
V IN Rising
3.8
4
4.2
V
--
400
--
mV
Enable Current
Under Voltage Lockout Threshold
Under Voltage Lockout Threshold
Hysteresis
V UVLO
ΔVUVLO
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Test Conditions
V EN = 0
V EN = 2V, VFB = 1V
V
μA
is a registered trademark of Richtek Technology Corporation.
DS8286-02
June 2012
RT8286
Parameter
Symbol
Test Conditions
VCC Regulator
VCC Load Regulation
ICC = 5mA
Min
Typ
Max
Unit
--
5
--
V
--
5
--
%
ms
Soft-Start Period
tSS
--
2
--
Thermal Shutdown
TSD
--
150
--
Thermal Shutdown Hysteresis
ΔTSD
--
30
--
°C
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 © 2012 Richtek Technology Corporation. All rights reserved.
DS8286-02
June 2012
is a registered trademark of Richtek Technology Corporation.
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RT8286
Typical Operating Characteristics
Reference Voltage vs. Input Voltage
Efficiency vs. Output Current
100
0.830
90
VIN = 12V
0.825
70
Reference Voltage (V)
Efficiency (%)
80
VIN = 21V
60
50
40
30
20
0.820
0.815
0.810
0.805
0.800
0.795
10
VOUT = 1.22V, IOUT = 0A to 2A
0
0.790
0
0.25
0.5
0.75
1
1.25
1.5
1.75
2
4
6
8
10
Output Current (A)
14
16
18
20
22
Input Voltage (V)
Reference Voltage vs. Temperature
Output Voltage vs. Output Current
0.84
1.240
0.83
1.235
0.82
1.230
Output Voltage (V)
Reference Voltage (V)
12
0.81
0.80
0.79
0.78
1.225
1.220
1.215
1.210
0.77
1.205
0.76
1.200
VIN = 12V, VOUT = 1.22V, IOUT = 0A to 2A
-50
-25
0
25
50
75
100
125
0
0.25
0.5
1
1.25
1.5
1.75
2
Switching Frequency vs. Temperature
Switching Frequency vs. Input Voltage
550
550
525
525
Switching Frequency (kHz)1
Switching Frequency (kHz)1
0.75
Output Current (A)
Temperature (°C)
500
475
450
425
400
375
500
475
450
425
400
375
VIN = 12V, VOUT = 1.22V, IOUT = 1A
VOUT = 1.22V, IOUT = 0.8A
350
350
4
6
8
10
12
14
16
18
20
Input Voltage (V)
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22
-50
-25
0
25
50
75
100
125
Temperature (°C)
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DS8286-02
June 2012
RT8286
Current Limit vs. Temperature
10
8
8
Current Limit (A)
Current Limit (A)
Current Limit vs. Input Voltage
10
6
4
6
4
2
2
0
0
VIN = 12V, VOUT = 1.22V
4
6
8
10
12
14
16
18
20
-50
22
0
25
50
75
100
Input Voltage (V)
Temperature (°C)
Load Transient Response
Load Transient Response
VOUT
(200mV/Div)
VOUT
(200mV/Div)
IOUT
(1A/Div)
IOUT
(1A/Div)
VIN = 12V, VOUT = 1.22V, IOUT = 0A to 2A
Time (100μs/Div)
Output Voltage Ripple
Output Voltage Ripple
VOUT
(50mV/Div)
VLX
(10V/Div)
VLX
(10V/Div)
IL
(2A/Div)
IL
(2A/Div)
VIN = 12V, IOUT = 1A
Time (1μs/Div)
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125
VIN = 12V, VOUT = 1.22V, IOUT = 1A to 2A
Time (100μs/Div)
VOUT
(50mV/Div)
DS8286-02
-25
VIN = 12V, IOUT = 2A
Time (1μs/Div)
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RT8286
Power On from VIN
Power Off from VIN
VIN
(10V/Div)
VIN
(10V/Div)
VOUT
(1V/Div)
VOUT
(1V/Div)
IL
(2A/Div)
IL
(2A/Div)
VIN = 12V, VOUT = 1.22V, IOUT = 2A
VIN = 12V, VOUT = 1.22V, IOUT = 2A
Time (5ms/Div)
Time (50ms/Div)
Power On from EN
Power Off from EN
VEN
(5V/Div)
VEN
(5V/Div)
VOUT
(1V/Div)
VOUT
(1V/Div)
VLX
(10V/Div)
VLX
(10V/Div)
IL
(2A/Div)
VIN = 12V, VOUT = 1.22V, IOUT = 2A
Time (2.5ms/Div)
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IL
(2A/Div)
VIN = 12V, VOUT = 1.22V, IOUT = 2A
Time (50μs/Div)
is a registered trademark of Richtek Technology Corporation.
DS8286-02
June 2012
RT8286
Application Information
The IC is a synchronous high voltage buck converter that
can support the input voltage range from 4.5V to 21V and
the output current can be up to 2A.
Output Voltage Setting
The output voltage is set by an external resistive divider
according to the following equation :
VOUT = VFB ⎛⎜ 1+ R1 ⎞⎟
⎝ R2 ⎠
where VFB is the feedback reference voltage 0.808V
(typical).
The resistive divider allows the FB pin to sense a fraction
of the output voltage as shown in Figure 1.
Soft-Start
The IC contains an internal soft-start function to prevent
large inrush current and output voltage overshoot when
the converter starts up. Soft-start automatically begins
once the chip is enabled. During soft-start, the internal
soft-start capacitor becomes charged and generates a
linear ramping up voltage across the capacitor. This voltage
clamps the voltage at the internal reference, causing the
duty pulse width to increase slowly and in turn reduce the
output surge current. Finally, the internal 1V reference
takes over the loop control once the internal ramping-up
voltage becomes higher than 1V. The typical soft-start
time for this IC is set at 2ms.
VOUT
Under Voltage Lockout Threshold
R1
FB
RT8286
R2
GND
Figure 1. Output Voltage Setting
External Bootstrap Diode
Connect a 100nF low ESR ceramic capacitor between
the BOOT pin and SW pin as shown in Figure 2. This
capacitor provides the gate driver voltage for the high side
MOSFET. It is recommended to add an external bootstrap
diode between an external 5V and BOOT pin for efficiency
improvement when input voltage is lower than 5.5V or duty
ratio is higher than 65% .The bootstrap diode can be a
low cost one such as IN4148 or BAT54. The external 5V
can be a 5V fixed input from system or a 5V output of the
IC. Note that the external boot voltage must be lower than
5.5V.
5V
BOOT
RT8286
100nF
The IC includes an input Under Voltage Lockout Protection
(UVLO). If the input voltage exceeds the UVLO rising
threshold voltage (4.2V), the converter resets and prepares
the PWM for operation. If the input voltage falls below the
UVLO falling threshold voltage (3.8V) during normal
operation, the device stops switching. The UVLO rising
and falling threshold voltage includes a hysteresis to
prevent noise caused reset.
Chip Enable Operation
The EN pin is the chip enable input. Pulling the EN pin
low (2V, < 5.5V) will turn on the
device again. For external timing control (e.g.RC), the
EN pin can also be externally pulled high by adding a
REN* resistor and CEN* capacitor from the VIN pin, as can
be seen from the Figure 5.
An external MOSFET can be added to implement digital
control on the EN pin when front age system voltage below
2.5V is available, as shown in Figure 3. In this case, a
100kΩ pull-up resistor, REN, is connected between VIN
and the EN pin. MOSFET Q1 will be under logic control
to pull down the EN pin.
SW
Figure 2. External Bootstrap Diode
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June 2012
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9
RT8286
1
VIN
REN
100k
BOOT
VIN
CIN
4
CBOOT
RT8286
SW
2, 3
L
VOUT
5 EN
R1
Chip Enable
FB 6
Q1
7
VCC
COUT
RT
R2
GND 8, 9 (Exposed Pad)
CC
Figure 3. Enable Control Circuit for Logic Control with Low Voltage
1
VIN
REN
100k
BOOT
VIN
CIN
4
CBOOT
RT8286
SW
2, 3
VOUT
5 EN
REN2
7
R1
FB 6
VCC
CC
L
COUT
RT
GND 8, 9 (Exposed Pad)
R2
Figure 4. The Resistors can be Selected to Set IC Lockout Threshold
To prevent enabling circuit when VIN is smaller than the
VOUT target value, a resistive voltage divider can be placed
between the input voltage and ground and connected to
the EN pin to adjust IC lockout threshold, as shown in
Figure 4. For example, if an 8V output voltage is regulated
from a 12V input voltage, the resistor REN2 can be selected
to set input lockout threshold larger than 8V.
Under Output Voltage Protection-Hiccup Mode
For the IC, Hiccup Mode of Under Voltage Protection (UVP)
is provided. When the FB voltage drops below half of the
feedback reference voltage, VFB, the UVP function will be
triggered and the IC will shut down for a period of time and
then recover automatically. The Hiccup Mode of UVP can
reduce input current in short-circuit conditions.
Inductor Selection
For a given input and output voltage, the inductor value
and operating frequency determine the ripple current. The
ripple current ΔIL increases with higher VIN and decreases
with higher inductance.
V
V
ΔIL = ⎡⎢ OUT ⎤⎥ × ⎡⎢1− OUT ⎤⎥
f
×
L
VIN ⎦
⎣
⎦ ⎣
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Having a lower ripple current reduces not only the ESR
losses in the output capacitors but also the output voltage
ripple. Highest efficiency operation is achieved by reducing
ripple current at low frequency, but it requires a large
inductor to attain this goal.
For the ripple current selection, the value of ΔIL = 0.24(IMAX)
will be a reasonable starting point. The largest ripple current
occurs at the highest VIN. To guarantee that the ripple
current stays below a specified maximum, the inductor
value should be chosen according to the following
equation :
⎡ VOUT ⎤ ⎡
VOUT ⎤
L =⎢
⎥ × ⎢1 −
⎥
⎣ f × ΔIL(MAX) ⎦ ⎣ VIN(MAX) ⎦
The inductor's current rating (caused a 40°C temperature
rising from 25°C ambient) should be greater than the
maximum load current and its saturation current should
be greater than the short circuit peak current limit. Please
see Table 2 for the inductor selection reference and it is
highly recommended to keep inductor value as close as
possible to the recommended inductor values for each
Vout as shown in Table 1.
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RT8286
Table 2. Suggested Inductors for Typical
Application Circuit
Component Supplier
Series
Dimensions (mm)
TDK
VLF10045
10 x 9.7 x 4.5
TDK
SLF12565
12.5 x 12.5 x 6.5
TAIYO YUDEN
NR8040
8x8x4
Input and Output Capacitors Selection
The input capacitance, C IN, is needed to filter the
trapezoidal current at the source of the high side MOSFET.
To prevent large ripple current, a low ESR input capacitor
sized for the maximum RMS current should be used. The
RMS current is given by :
V
IRMS = IOUT(MAX) OUT
VIN
This formula has a maximum at VIN = 2VOUT, where IRMS =
IOUT / 2. This simple worst case condition is commonly
used for design because even significant deviations do
not offer much relief.
Choose a capacitor rated at a higher temperature than
required. Several capacitors may also be paralleled to
meet size or height requirements in the design.
For the input capacitor, one 22μF low ESR ceramic
capacitors are recommended. For the recommended
capacitor, please refer to Table 3 for more detail.
VIN
−1
VOUT
Table 3. Suggested Capacitors for CIN and COUT
Location
Component Supplier
Part No.
Capacitance (μF)
Case Size
CIN
MURATA
GRM32ER71C226M
22
1210
CIN
TDK
C3225X5R1C226M
22
1210
COUT
MURATA
GRM31CR60J476M
47
1206
COUT
TDK
C3225X5R0J476M
47
1210
COUT
MURATA
GRM32ER71C226M
22
1210
COUT
TDK
C3225X5R1C226M
22
1210
The selection of COUT is determined by the required ESR
to minimize voltage ripple.
Moreover, the amount of bulk capacitance is also a key
for COUT selection to ensure that the control loop is stable.
Loop stability can be checked by viewing the load transient
response.
The output ripple, ΔVOUT, is determined by :
1
⎤
ΔVOUT ≤ ΔIL ⎡⎢ESR +
8fCOUT ⎦⎥
⎣
Higher values, lower cost ceramic capacitors are now
becoming available in smaller case sizes. Their high ripple
current, high voltage rating and low ESR make them ideal
for switching regulator applications. However, care must
be taken when these capacitors are used at input and
output. When a ceramic capacitor is used at the input
Copyright © 2012 Richtek Technology Corporation. All rights reserved.
DS8286-02
June 2012
and the power is supplied by a wall adapter through long
wires, a load step at the output can induce ringing at the
input, VIN. At best, this ringing can couple to the output
and be mistaken as loop instability. At worst, a sudden
inrush of current through the long wires can potentially
cause a voltage spike at VIN large enough to damage the
part.
Thermal Shutdown
Thermal shutdown is implemented to prevent the chip from
operating at excessively high temperatures. When the
junction temperature is higher than 150°C, the whole chip
is shutdown. The chip is automatically re-enable when
the junction temperature cools down by approximately
30 degrees.
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RT8286
EMI Consideration
Figure 5. Another method is by adding a resistor in series
with the bootstrap capacitor, CBOOT, but this method will
decrease the driving capability to the high side MOSFET.
It is strongly recommended to reserve the R-C snubber
during PCB layout for EMI improvement. Moreover,
reducing the SW trace area and keeping the main power
in a small loop will be helpful on EMI performance. For
detailed PCB layout guide, please refer to the section
Layout Considerations.
Since parasitic inductance and capacitance effects in PCB
circuitry would cause a spike voltage on SW pin when
high side MOSFET is turned-on/off, this spike voltage on
SW may impact on EMI performance in the system. In
order to enhance EMI performance, there are two methods
to suppress the spike voltage. One way is by placing an
R-C snubber (RS*, CS*) between SW and GND and locating
them as close as possible to the SW pin, as shown in
1
VIN
REN*
BOOT
VIN
CIN
CBOOT
RT8286
SW
5
4
L
2, 3
VOUT
CS*
EN
COUT
R1
RS *
CEN*
7
VCC
CC
RT
FB 6
GND 8, 9 (Exposed Pad)
R2
* : Optional
Figure 5. Reference Circuit with Snubber and Enable Timing Control
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 :
PD(MAX) = (TJ(MAX) − TA) / θJA
where TJ(MAX) is the maximum junction temperature, TA is
the ambient temperature, and θJA is the junction to ambient
thermal resistance.
For recommended operating condition specifications, the
maximum junction temperature is 125°C. The junction to
ambient thermal resistance, θJA, is layout dependent. For
SOP-8 (Exposed Pad) packages, the thermal resistance,
θJA, is 75°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 :
The maximum power dissipation depends on the operating
ambient temperature for fixed T J(MAX) and thermal
resistance, θJA. The derating curve in Figure 6 allows the
designer to see the effect of rising ambient temperature
on the maximum power dissipation.
1.4
Maximum Power Dissipation (W)
Thermal Considerations
Four-Layer PCB
1.2
1.0
0.8
0.6
0.4
0.2
0.0
0
25
50
75
100
125
Ambient Temperature (°C)
Figure 6. Derating Curve of Maximum Power Dissipation
PD(MAX) = (125°C − 25°C) / (75°C/W) = 1.333W for
SOP-8 (Exposed Pad) package
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June 2012
RT8286
Layout Considerations
`
Connect feedback network behind the output capacitors.
Keep the loop area small. Place the feedback
components near the IC.
`
Connect all analog grounds to a common node and then
connect the common node to the power ground behind
the output capacitors.
`
An example of PCB layout guide is shown in Figure 7.
for reference.
Follow the PCB layout guidelines for optimal performance
of the IC.
`
Keep the traces of the main current paths as short and
wide as possible.
`
Put the input capacitor as close as possible to the device
pins (VIN and GND).
`
SW node is with high frequency voltage swing and
should be kept at small area. Keep analog components
away from the SW node to prevent stray capacitive noise
pickup.
Place the input and
output capacitors
as close to the IC
as possible.
GND
CIN
SW should be connected
to inductor by wide and
short trace and keep
sensitive components
away from this trace.
L
CBOOT
VIN
8
SW
2
SW
3
BOOT
4
VOUT
GND
GND
7
VCC
6
FB
5
EN
9
RT
R2
R1
Place the feedback
as close to the IC as
possible.
VOUT
COUT
GND
Figure 7. PCB Layout Guide
Copyright © 2012 Richtek Technology Corporation. All rights reserved.
DS8286-02
June 2012
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
13
RT8286
Outline Dimension
H
A
M
EXPOSED THERMAL PAD
(Bottom of Package)
Y
J
X
B
F
C
I
D
Dimensions In Millimeters
Dimensions In Inches
Symbol
Min
Max
Min
Max
A
4.801
5.004
0.189
0.197
B
3.810
4.000
0.150
0.157
C
1.346
1.753
0.053
0.069
D
0.330
0.510
0.013
0.020
F
1.194
1.346
0.047
0.053
H
0.170
0.254
0.007
0.010
I
0.000
0.152
0.000
0.006
J
5.791
6.200
0.228
0.244
M
0.406
1.270
0.016
0.050
X
2.000
2.300
0.079
0.091
Y
2.000
2.300
0.079
0.091
X
2.100
2.500
0.083
0.098
Y
3.000
3.500
0.118
0.138
Option 1
Option 2
8-Lead SOP (Exposed Pad) Plastic Package
Richtek Technology Corporation
5F, No. 20, Taiyuen 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
14
DS8286-02
June 2012
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