®
RT7263B
3A, 21V 500kHz Synchronous Step-Down Converter
General Description
Features
The RT7263B is a synchronous step-down regulator with
an internal power MOSFET. It achieves 3A 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.
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Wide Input Range : 4.5V to 21V
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Adjustable Output from 0.603V to 15V
3A Output Current
120mΩ
Ω/40mΩ
Ω Internal Power MOSFET Switch
Internal Compensation Minimizes External Parts
500kHz Fixed Switching Frequency
Synchronized External Clock from 300kHz to 2MHz
Adjustable Soft-Start
Cycle-by-Cycle Over Current Limit
Thermal Shutdown Protection
Small 14-Lead WDFN Package
RoHS Compliant and Halogen Free
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Fault condition protection includes cycle-by-cycle current
limiting and thermal shutdown. An adjustable soft-start
reduces the stress on the input source at startup.
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The RT7263B requires a minimal number of readily
available external components, providing a compact
solution.
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Ordering Information
Applications
RT7263B
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Package Type
QW : WDFN-14L 4x3 (W-Type)
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Lead Plating System
Z : ECO (Ecological Element with
Halogen Free and Pb free)
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Distributive Power Systems
Battery Charger
DSL Modems
Pre-Regulator for Linear Regulators
Marking Information
Note :
10 : Product Code
Richtek products are :
`
10 YM
DNN
RoHS compliant and compatible with the current requirements of IPC/JEDEC J-STD-020.
`
YMDNN : Date Code
Suitable for use in SnPb or Pb-free soldering processes.
Simplified Application Circuit
VIN
VIN
CIN
BOOT
RT7263B
CBOOT
L
VCC
SW
VOUT
CC
RT
SYNC
ON/OFF
SYNC
EN
AGND
Copyright © 2012 Richtek Technology Corporation. All rights reserved.
DS7263B-01
September 2012
R1
COUT
FB
CSS
SS
R2
GND
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1
RT7263B
Pin Configurations
(TOP VIEW)
VIN
SW
SW
SW
SW
BOOT
SYNC
14
13
1
2
3
4
5
6
7
GND
15
12
11
10
9
8
AGND
GND
GND
VCC
SS
EN
FB
WDFN-14L 4x3
Function Pin Description
Pin No.
Pin Name
Pin Function
1
VIN
Power 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.
2, 3, 4, 5
SW
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.
6
BOOT
Bootstrap for High Side Gate Driver. Connect a 100nF or greater capacitor from
SW to BOOT to power the high side switch driver.
7
SYNC
External Frequency Synchronization Input. Connect an external clock on this pin
changes the switching frequency.
8
FB
Feedback Input. FB senses the output voltage via an external resistive voltage
divider. The feedback reference voltage is 0.603V typically.
9
EN
Enable Control Input. Floating this pin or connecting this pin to logic high will
enable the device and connecting this pin to GND will disable the device.
10
SS
Soft-Start Control Input. Connect a capacitor from SS to GND to set the soft-start
period.
11
VCC
Bias Supply. Decouple with 0.1μF to 0.22μF capacitor between this pin and
GND.
12, 13,
GND
15 (Exposed Pad)
Ground. The exposed pad must be soldered to a large PCB and connected to
GND for maximum power dissipation.
14
AGND
Analog Ground. Connect this pin to the system ground in PCB layout.
Copyright © 2012 Richtek Technology Corporation. All rights reserved.
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is a registered trademark of Richtek Technology Corporation.
DS7263B-01
September 2012
RT7263B
Function Block Diagram
VIN
VCC
EN
Current Sense
Amplifier
-
Ramp
Generator
+
Regulator
BOOT
S
Oscillator
Q
+
SYNC
OC Limit
Clamp
Reference
FB
10µA
SS
Driver
R
PWM
Comparator
SW
Error
Amplifier
+
+
-
GND
400k
30pF
1pF
Operation
The RT7263B is a constant frequency, current mode
synchronous step-down converter. In normal operation,
the high side N-MOSFET is turned on when the S-R latch
is set by the oscillator and is turned off when the current
comparator resets the S-R latch. While the high side
N-MOSFET is turned off, the low side N-MOSFET is turned
on to conduct the inductor current until next cycle begins.
Error Amplifier
The error amplifier adjusts its output voltage by comparing
the feedback signal (VFB) with the internal reference. When
the load current increases, it causes a drop in the feedback
voltage relative to the reference, the error amplifier's output
voltage then rises to allow higher inductor current to match
the load current.
Oscillator
The internal oscillator runs at fixed frequency 500kHz. In
short circuit condition, the frequency is reduced to 150kHz
for low power consumption.
Internal Regulator
The regulator provides low voltage power to supply the
internal control circuits and the bootstrap power for high
side gate driver.
Copyright © 2012 Richtek Technology Corporation. All rights reserved.
DS7263B-01
September 2012
Enable
The converter is turned on when the EN pin is higher than
2V. When the EN pin is lower than 0.4V, the converter will
enter shutdown mode and reduce the supply current to
be less than 1μA.
Soft-Start (SS)
An internal current source charges an internal capacitor
to build a soft-start ramp voltage. The FB voltage will track
the internal ramp voltage during soft-start interval. The
typical soft-start time is 4ms.
UV Comparator
If the feedback voltage (VFB) is lower than 0.4V, the UV
Comparator will go high to turn off the high side MOSFET.
The output under voltage protection is designed to operate
in Hiccup mode. When the UV condition is removed, the
converter will resume switching.
Thermal Shutdown
The over temperature protection function will shut down
the switching operation when the junction temperature
exceeds 150°C. Once the junction temperature cools
down by approximately 30°C, the converter will
automatically resume switching.
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3
RT7263B
Absolute Maximum Ratings
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(Note 1)
Supply Input Voltage, VIN ---------------------------------------------------------------------------------Switch Voltage, SW ----------------------------------------------------------------------------------------Boot Voltage, BOOT ----------------------------------------------------------------------------------------Other Pins -----------------------------------------------------------------------------------------------------Power Dissipation, PD @ TA = 25°C
WDFN-14L 4x3 -----------------------------------------------------------------------------------------------Package Thermal Resistance (Note 2)
WDFN-14L 4x3, θJA -----------------------------------------------------------------------------------------WDFN-14L 4x3, θJC -----------------------------------------------------------------------------------------Junction Temperature ---------------------------------------------------------------------------------------Lead Temperature (Soldering, 10 sec.) -----------------------------------------------------------------Storage Temperature Range ------------------------------------------------------------------------------ESD Susceptibility (Note 3)
HBM (Human Body Model) ---------------------------------------------------------------------------------
Recommended Operating Conditions
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−0.3V to 26V
−0.3V to (VIN + 0.3V)
(SW − 0.3V) to (SW + 6V)
−0.3V to 6V
1.667W
60°C/W
7°C/W
150°C
260°C
−65°C to 150°C
2kV
(Note 4)
Supply Input Voltage, VIN ---------------------------------------------------------------------------------- 4.5V to 21V
Junction Temperature Range ------------------------------------------------------------------------------- −40°C to 125°C
Ambient Temperature Range ------------------------------------------------------------------------------- −40°C to 85°C
Electrical Characteristics
(VIN = 12V, TA = 25°C unless otherwise specified)
Parameter
Symbol
Test Conditions
Min
Typ
Max
Unit
Shutdown Current
ISHDN
VEN = 0
--
0
1
μA
Quiescent Current
IQ
VEN = 2V, VFB = 1V
--
0.7
--
mA
Upper Switch On Resistance
R DS(ON)1
--
120
--
mΩ
Lower Switch On Resistance
R DS(ON)2
--
40
--
mΩ
Switch Leakage
ILEAK
VEN = 0V, VSW = 0V or 12V
--
0
10
μA
Current Limit
ILIMIT
VBOOT − VSW = 4.8V
5.4
6.5
--
A
Oscillator Frequency
fSW
VFB = 0.75V
425
500
575
kHz
VFB = 0V
--
150
--
kHz
VFB = 0.8V
--
90
--
%
--
100
--
ns
Short Circuit Frequency
Maximum Duty Cycle
D MAX
Minimum On Time
tON
Feedback Voltage
VFB
Feedback Current
IFB
--
10
50
Logic-High
VIH
2
--
5.5
Logic-Low
VIL
--
--
0.4
VEN = 2V
--
1
--
VEN = 0V
--
0
--
EN Voltage
Enable Current
4.5V ≤ VIN ≤ 21V
Copyright © 2012 Richtek Technology Corporation. All rights reserved.
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4
0.593 0.603 0.613
V
nA
V
μA
is a registered trademark of Richtek Technology Corporation.
DS7263B-01
September 2012
RT7263B
Parameter
Symbol
Test Conditions
Min
Typ
Max
Unit
SYNC Threshold Logic-High
Voltage
Logic-Low
VSYNCH
1.8
--
--
VSYNCL
--
--
0.4
SYNC Frequency Range
fSYNC
0.3
--
2
MHz
SYNC Input Current
ISYNC
VSYNC = 6V
--
1.5
2.5
μA
Under Voltage Lockout
Threshold
VUVLO
VIN Rising
3.8
4
4.2
V
Under Voltage Lockout
Threshold Hysteresis
ΔVUVLO
--
400
--
mV
--
5
--
V
ICC = 5mA
--
5
--
%
CSS = 47nF
--
4.7
--
ms
VCC Regulator
VCC Load Regulation
Soft-Start Period
tSS
Thermal Shutdown Threshold
TSD
--
150
--
Thermal Shutdown Hysteresis
ΔTSD
--
30
--
V
°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.
DS7263B-01
September 2012
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
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RT7263B
Typical Application Circuit
1
VIN
BOOT
VIN
CIN
22µF
6
CBOOT
100nF
RT7263B
11
VCC
SW
CC
0.1µF
2, 3, 4, 5
FB 8
SYNC
ON/OFF
7 SYNC
SS 10
9 EN
L
VOUT
R1
RT
COUT
CSS
47nF
R2
GND
12, 13, 15 (Exposed Pad)
AGND
14
Table 1. Recommended Components Selection
VOUT (V)
R1 (kΩ)
R2 (kΩ)
RT (kΩ)
L (μH)
COUT (μF)
5
75
10.23
0
4.7
22 x 2
3.3
75
16.67
0
3.6
22 x 2
2.5
75
23.68
0
3.6
22 x 2
1.8
5
2.5
24
2
22 x 2
1.5
5
3.33
27
2
22 x 2
1.2
5
5
36
2
22 x 2
1.05
5
6.67
39
1.5
22 x 2
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is a registered trademark of Richtek Technology Corporation.
DS7263B-01
September 2012
RT7263B
Typical Operating Characteristics
Efficiency vs. Output Current
Reference Voltage vs. Input Voltage
100
0.620
90
0.615
70
Reference Voltage (V)
Efficiency (%)
80
VIN = 12V
VIN = 21V
60
50
40
30
20
0.610
0.605
0.600
0.595
0.590
0.585
10
VOUT = 1.2V, IOUT = 0A to 3A
0
0.580
0
0.5
1
1.5
2
2.5
3
4
6
8
10
14
16
18
20
22
Input Voltage (V)
Output Current (A)
Output Voltage vs. Output Current
Reference Voltage vs. Temperature
0.64
1.24
0.63
1.23
0.62
1.22
Output Voltage (V)
Reference Voltage (V)
12
0.61
0.60
0.59
0.58
1.21
1.20
VIN = 21V
VIN = 12V
1.19
1.18
0.57
1.17
0.56
1.16
VOUT = 1.2V, IOUT = 0A to 3A
-50
-25
0
25
50
75
100
125
0
0.5
1
Temperature (°C)
Switching Frequency vs. Input Voltage
2
2.5
3
Switching Frequency vs. Temperature
550
650
Switching Frequency (kHz)1
Switching Frequency (kHz)1
1.5
Output Current (A)
525
500
475
450
425
600
550
500
450
400
350
VOUT = 1.2V
400
VIN = 12V, VOUT = 1.2V
300
4
6
8
10
12
14
16
18
20
Input Voltage (V)
Copyright © 2012 Richtek Technology Corporation. All rights reserved.
DS7263B-01
September 2012
22
-50
-25
0
25
50
75
100
125
Temperature (°C)
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RT7263B
Current Limit vs. Temperature
12
10
10
Current Limit (A)
Current Limit (A)
Current Limit vs. Input Voltage
12
8
6
4
8
6
4
2
2
0
0
VIN = 12V, VOUT = 1.2V
4
6
8
10
12
14
16
18
20
22
-50
0
25
50
75
100
Input Voltage (V)
Temperature (°C)
Load Transient Response
Load Transient Response
VOUT
(500mV/Div)
VOUT
(200mV/Div)
IOUT
(1A/Div)
IOUT
(1A/Div)
VIN = 12V, VOUT = 1.2V, IOUT = 0A to 3A
Time (100μs/Div)
Output Ripple Voltage
Output Ripple Voltage
VOUT
(50mV/Div)
VSW
(10V/Div)
VSW
(10V/Div)
IL
(1A/Div)
IL
(2A/Div)
VIN = 12V, IOUT = 3A
VIN = 12V, IOUT = 1A
Time (1μs/Div)
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VIN = 12V, VOUT = 1.2V, IOUT = 1A to 3A
Time (100μs/Div)
VOUT
(50mV/Div)
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-25
Time (1μs/Div)
is a registered trademark of Richtek Technology Corporation.
DS7263B-01
September 2012
RT7263B
Power On from VIN
Power Off from VIN
VIN
(10V/Div)
VIN
(10V/Div)
VOUT
(1V/Div)
VSW
(20V/Div)
VOUT
(1V/Div)
VSW
(20V/Div)
IL
(5A/Div)
IL
(5A/Div)
VIN = 12V, VOUT = 1.2V, IOUT = 3A
Time (5ms/Div)
Time (25ms/Div)
Power On from EN
Power Off from EN
VEN
(5V/Div)
VEN
(5V/Div)
VOUT
(1V/Div)
VSW
(20V/Div)
VOUT
(1V/Div)
VSW
(20V/Div)
IL
(5A/Div)
IL
(5A/Div)
VIN = 12V, VOUT = 1.2V, IOUT = 3A
Time (2.5ms/Div)
Copyright © 2012 Richtek Technology Corporation. All rights reserved.
DS7263B-01
VIN = 12V, VOUT = 1.2V, IOUT = 3A
September 2012
VIN = 12V, VOUT = 1.2V, IOUT = 3A
Time (50μs/Div)
is a registered trademark of Richtek Technology Corporation.
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RT7263B
Application Information
The IC is a synchronous high voltage step-down converter
that can support the input voltage range from 4.5V to 21V
and the output current can be up to 3A.
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 0.603V (typ.).
The resistive divider allows the FB pin to sense a fraction
of the output voltage as shown in Figure 1.
VOUT
R1
FB
RT7263B
R2
Soft-Start
The IC contains an external soft-start clamp that gradually
raises the output voltage. The soft-start timing is
programmed by the external capacitor between SS pin
and GND. The chip provides an internal 10μA charge current
for the external capacitor. If 47nF capacitor is used to set
the soft-start, the period will be 4.7ms (typ.).
Under Voltage Lockout Threshold
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.
GND
Chip Enable Operation
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.
The EN pin is the chip enable input. Pulling the EN pin
low (2V). If the EN pin is
pulled to low-level for 10μs above, the IC will shut down.
The RT7263B can be synchronized with an external clock
ranging from 300kHz to 2MHz applied to the EN/SYNC
pin. The external clock duty cycle must be from 30% to
90%.
Copyright © 2012 Richtek Technology Corporation. All rights reserved.
DS7263B-01
September 2012
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 ⎤⎥
VIN ⎦
⎣ f ×L ⎦ ⎣
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.
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RT7263B
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) ⎦
Input and Output Capacitors Selection
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.
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.
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
VIN
−1
VOUT
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.
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
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
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12
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
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.
is a registered trademark of Richtek Technology Corporation.
DS7263B-01
September 2012
RT7263B
Thermal Shutdown
Maximum Power Dissipation (W)1
1.80
Thermal shutdown in implemented to prevent the chip from
operating at excessively high temperatures. When the
junction temperature is higher than 150°C, the chip is
shut down the switching operation. The chip is
automatically re-enabled when the junction temperature
cools down by approximately 30°C.
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 :
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
WDFN-14L 4x3 package, the thermal resistance, θJA, is
60°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 :
Copyright © 2012 Richtek Technology Corporation. All rights reserved.
DS7263B-01
September 2012
1.50
1.20
0.90
0.60
0.30
0.00
0
25
50
75
100
125
Ambient Temperature (°C)
Figure 7. Derating Curve of Maximum Power Dissipation
Layout Considerations
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.
`
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 command node to the power ground behind
the output capacitors.
`
An example of PCB layout guide is shown in Figure 8
for reference.
PD(MAX) = (125°C − 25°C) / (60°C/W) = 1.667W for
WDFN-14L 4x3 package
The maximum power dissipation depends on the operating
ambient temperature for fixed T J(MAX) and thermal
resistance, θJA. The derating curve in Figure 7 allows the
designer to see the effect of rising ambient temperature
on the maximum power dissipation.
Four-Layer PCB
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
13
RT7263B
SW should be connected to inductor by
wide and short trace and keep sensitive
components away from this trace.
GND
CIN
VIN
SW
SW
SW
CBOOT SW
BOOT
SYNC
1
14
2
13
3
4
5
6
GND
15
7
L
VOUT
COUT
12
11
10
9
8
AGND
GND CSS
GND
VCC
SS
EN
FB
RT
R2
R1
Place the feedback
components as close
to the IC as possible.
VOUT
GND
Place the input and output
capacitors as close to the
IC as possible.
Figure 8. PCB Layout Guide
Copyright © 2012 Richtek Technology Corporation. All rights reserved.
www.richtek.com
14
is a registered trademark of Richtek Technology Corporation.
DS7263B-01
September 2012
RT7263B
Outline Dimension
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.
Dimensions In Millimeters
Dimensions In Inches
Symbol
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
0.180
0.300
0.007
0.012
D
3.900
4.100
0.154
0.161
D2
3.250
3.350
0.128
0.132
E
2.900
3.100
0.114
0.122
E2
1.650
1.750
0.065
0.069
e
L
0.500
0.350
0.020
0.450
0.014
0.018
W-Type 14L DFN 4x3 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.
DS7263B-01
September 2012
www.richtek.com
15
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