YOBON YB1683SPX8P

YB1683
3A 380KHz 28V PWM Buck DC/DC Converter
Description
Features
The YB1683 is a 380 KHz fixed frequency
monolithic step down switch mode
regulator with a built in internal Power
MOSFET. It achieves 3A continuous output
current over a wide input supply range with
excellent load and line regulation.
The device includes a voltage reference,
oscillation circuit, error amplifier, internal
PMOS and etc.
„ 3A Constant Output Current
The PWM control circuit is able to adjust
the duty ratio linearly from 0 to 100%. An
enable function, an over current protection
function and a short circuit protection
function are built inside. An internal
compensation block is built in to minimize
external component count.
„
The YB1683 serves as ideal power supply
units for portable devices.
„ LCD Monitor / TV
„ 140mΩ RDSON Internal Power PMOSFET
„
„
„
„
„
„
„
Switch
Up to 92% Efficiency
Fixed 380KHz Frequency
Wide 3.6V to 28V Input Voltage Range
Output Adjustable from 1.222V to 26V
Output Current Protection
Built in Frequency Compensation
Built in Thermal Shutdown Function
Built in Current Limit Function
„ SOP8 Package is Available
„ The Minimum Dropout up to 0.3V
„ Pb-free Package
Applications
„ Portable DVD
„ Battery Charger
„ ADSL Modem
„ Telecom / Networking Equipment
Typical Application Circuit
Figure 1: Typical Application Circuit
YB1683 Rev.1.0
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YB1683
3A 380KHz 28V PWM Buck DC/DC Converter
Pin Configuration
NC
1
8
NC
VIN
2
7
EN
SW
3
6
NC
GND
4
5
FB
SOP-8
Figure 2: Pin Configuration
Pin Description
Table 1
Pin
Name
Description
1,6,8
NC
Not Connect.
2
VIN
Supply Voltage Input Pin. YB1683 operates from a 3.6V to 28VDC
voltage.
Bypass VIN to GND with a suitably large capacitor to eliminate noise
on the input.
3
SW
Power Switch Output Pin. SW is the switch node that supplies
power to the output.
Ground Pin. Care must be taken in layout. This pin should be
placed outside of the Schottky Diode to output capacitor ground
path to prevent switching current spikes from inducing voltage
noise into YB1683.
4
GND
5
FB
Feedback Pin. Through an external resistor divider network, FB
senses the output voltage and regulates it. The feedback threshold
voltage is 1.222V.
7
EN
Enable Pin. EN is a digital input that turns the regulator on or off.
Drive EN pin high to turn on the regulator, drive it low to turn it off.
Ordering Information
Order Number
Package Type
Supplied As
Package Marking
YB1683SPX8P
SOP-8
2500 units Tape & Reel
Please contact sales
representative
YB1683 Rev.1.0
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YB1683
3A 380KHz 28V PWM Buck DC/DC Converter
Absolute Maximum Ratings
Recommended Operating Conditions
Input Voltage............................. -0.3V to 28V
Feedback Pin Voltage .................-0.3V to VIN
Enable Pin Voltage.................... -0.3V to 12V
Switch Pin Voltage ......................-0.3V to VIN
Power Dissipation .............. Internally Limited
Operating Junction Temperature......... 150°C
Storage Temperature ............ -65°C to 150°C
Input Voltage............................ 3.6V to 28V
Operating Junction Temperature ... -40°C to 125°C
Operating Ambient Temperature.......-40°C to 85°C
Lead Temperature (Soldering, 10 sec)... 260°C
ESD (HBM).......................................2000V
Note:
Stresses greater than those listed under Maximum Ratings may cause permanent damage to the device. This
is a stress rating only and functional operation of the device at these or any other conditions above those
indicated in the operation is not implied. Exposure to absolute maximum rating conditions for extended
periods may affect reliability.
Electrical Characteristics
Table 2
(VCC = 12V, TA=25°C, unless otherwise specified.)
Description
Input Voltage
Shutdown Supply Current
Symbol
Test Conditions
VIN
ISTBY
MIN
TYP
3.6
MAX
Units
28
V
VEN = 0V
30
90
µA
3.6
4
mA
1.222
1.26
V
0.1
0.5
µA
4
5
A
Supply Current
ICC
VEN = 2V, VFB = 1.3V
Feedback Voltage
VFB
VIN = 3.6V to 23V
Feedback Bias Current
IFB
VFB = 1.3V
Switch Current Limit
ILIM
Oscillator Frequency
FOSC
320
380
440
KHz
EN Pin Threshold
VEN
0.7
1.2
1.7
V
1.21
EN Pin Input Leakage
Current
IH
VEN = 2.5V
-0.1
-1
µA
IL
VEN = 0.5V
-3
-10
µA
Internal PMOS RDSON
RDSON
VIN ≦ 12V, VFB =0V
VEN = 12V, IOUT = 3A
80
mΩ
Max. Duty Cycle
DMAX
VFB = 0V, ISW = 0.1A
100
%
VIN = 12V, VOUT = 5V, IOUT = 3A
92
%
165
°C
Efficiency
Thermal Shutdown
YB1683 Rev.1.0
η
TOTSD
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YB1683
3A 380KHz 28V PWM Buck DC/DC Converter
Typical Performance Characteristics
Efficiency V.S Load (Vin=12V)
System Efficiency(%)
100%
90%
80%
2.5V
70%
3.3V
60%
5V
50%
0
0.5
1
1.5
2
2.5
3
Output Load Current(A)
YB1683 Rev.1.0
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YB1683
3A 380KHz 28V PWM Buck DC/DC Converter
Function Block
Figure 3: Function Block
Functional Description
VIN
This is the positive input supply for the IC
switching regulator. A suitable input bypass
capacitor must be present at this pin to
minimize voltage transients and to supply
the switching currents needed by the
regulator.
Gnd
Circuit ground.
SW
Internal switch. The voltage at this pin
and
switches between
(VIN – VGS)
approximately – 0.5V, with a duty cycle of
approximately VOUT / VIN. To minimize
coupling to sensitive circuitry, the PC board
copper area connected to this pin should
be kept a minimum.
YB1683 Rev.1.0
FB
Senses the regulated output voltage to
complete the feedback loop.
EN
Allows the switching regulator circuit to be
shutdown using logic level signals thus
dropping the total input supply current to
approximately 30µA.Pulling this pin below a
threshold voltage of approximately 0.7 V
turns the regulator down, and pulling this
pin above 1.3V (up to a maximum of 12V)
shuts the regulator on.
For automatic star up condition, can be
implemented by the addition of a resistive
voltage divider from VIN to GND.
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YB1683
3A 380KHz 28V PWM Buck DC/DC Converter
Thermal Considerations
The SOP8 package needs a heat sink
under most conditions. The size of the heat
sink depends on the input voltage, the
output voltage, the load current and the
ambient temperature. The YB1683 junction
temperature
rises
above
ambient
temperature for a 3A load and different
input and output voltages. The data for
these curves was taken with the YB1683
(SOP8
package)
operating
as
a
buck-switching regulator in an ambient
temperature of 25 ºC (still air). These
temperature rise numbers are all
approximate and there are many factors
that can affect these temperatures. Higher
ambient temperatures require more heat
sinking.
copper Thick ness, single or double-sided,
multi-layer board and the amount of solder
on the board.
The effectiveness of the PC board to
dissipate heat also depends on the size,
quantity and spacing of other components
on the board, as well as whether the
surrounding air is still or moving.
Furthermore, some of these components
such as the catch diode will add heat to the
PC board and the heat can vary as the
input voltage changes. For the inductor,
depending on the physical size, type of
core material and the DC resistance, it
could either act as a heat sink taking heat
away from the board, or it could add heat to
the board.
For the best thermal performance, wide
copper traces and generous amounts of
printed circuit board copper should be used
in the board layout. (Once exception to this
is the output (switch) pin, which should not
have large areas of copper.) Large areas of
copper provide the best transfer of heat
(lower
thermal
resistance)
to
the
surrounding air, and moving air lowers the
thermal resistance even further.
Package thermal resistance and junction
temperature rise numbers are all
approximate, and there are many factors
that will affect these numbers. Some of
these factors include board size, shape,
thickness, position, location, and even
board temperature. Other factors are, trace
width, total printed circuit copper area,
YB1683 Rev.1.0
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YB1683
3A 380KHz 28V PWM Buck DC/DC Converter
Typical Application Circuit
YB1683 Rev.1.0
www.yobon.com.tw
7
YB1683
3A 380KHz 28V PWM Buck DC/DC Converter
Schottky Rectifier Selection Guide
YB1683 Lists some rectifier manufacturers.
VIN (Max)
3A Load Current
Part Number
20V
30V
Vendor
B320
Diodes, Inc.
SK33
Diodes, Inc.
SS32
General Semiconductor
B330
Diodes, Inc.
B340L
Diodes, Inc.
On Semiconductor
MBRD330
SK33
Diodes, Inc.
SS33
General Semiconductor
Output Voltage vs. R1, R2 Resistor Selection Guide ( VOUT = ( 1 + R1 / R2 ) * 1.222V )
YB1683 VOUT vs. R1, R2 Select Table
VOUT
R1
R2
1.8V
3.9K
8.2K
2.5V
3.2K
3K
3.3V
6.2K
3.6K
5V
6.2K
2K
9V
13K
2K
12V
16K
1.8K
YB1683 Rev.1.0
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YB1683
3A 380KHz 28V PWM Buck DC/DC Converter
Package Information (SOP-8)
NOTICE:
y The information described herein is subject to change without notice.
y Yobon does not assume any responsibility for use of any circuitry or applications described herein, nor
does it convey any patent license.
YB1683 Rev.1.0
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