YB1683
3A 380KHz 28V PWM Buck DC/DC Converter
Description
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.
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.
Features
3A Constant Output Current
140mΩ R
DSON
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
LCD Monitor / TV
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
VIN
SW
GND
1
2
3
4
SOP-8
8
7
6
5
NC
EN
NC
FB
Figure 2: Pin Configuration
Pin Description
Table 1
Pin
1,6,8
Name
NC
Not Connect.
Description
2
VIN
Supply Voltage Input Pin. YB1683 operates from a 3.6V to 28VDC
voltage.
Bypass V
IN
to GND with a suitably large capacitor to eliminate noise
on the input.
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.
Feedback Pin. Through an external resistor divider network, FB
senses the output voltage and regulates it. The feedback threshold
voltage is 1.222V.
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.
3
SW
4
GND
5
FB
7
EN
Ordering Information
Order Number
YB1683SPX8P
Package Type
SOP-8
Supplied As
2500 units Tape & Reel
Package Marking
Please contact sales
representative
2
YB1683 Rev.1.0
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YB1683
3A 380KHz 28V PWM Buck DC/DC Converter
Absolute Maximum Ratings
Input Voltage............................. -0.3V to 28V
Feedback Pin Voltage .................-0.3V to V
IN
Enable Pin Voltage.................... -0.3V to 12V
Switch Pin Voltage ......................-0.3V to V
IN
Power Dissipation .............. Internally Limited
Operating Junction Temperature......... 150°C
Storage Temperature ............ -65°C to 150°C
Recommended Operating Conditions
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
(V
CC
= 12V, T
A
=25°C, unless otherwise specified.)
Description
Input Voltage
Shutdown Supply Current
Supply Current
Feedback Voltage
Feedback Bias Current
Switch Current Limit
Oscillator Frequency
EN Pin Threshold
EN Pin Input Leakage
Current
Internal PMOS R
DSON
Max. Duty Cycle
Efficiency
Thermal Shutdown
Symbol
V
IN
I
STBY
I
CC
V
FB
I
FB
I
LIM
F
OSC
V
EN
I
H
I
L
R
DSON
D
MAX
η
T
OTSD
V
EN
= 2.5V
V
EN
= 0.5V
V
IN
≦
12V, V
FB
=0V
V
EN
= 12V, I
OUT
= 3A
V
FB
= 0V, I
SW
= 0.1A
V
IN
= 12V, V
OUT
= 5V, I
OUT
= 3A
320
0.7
V
EN
= 0V
V
EN
= 2V, V
FB
= 1.3V
V
IN
= 3.6V to 23V
V
FB
= 1.3V
1.21
Test Conditions
MIN
3.6
30
3.6
1.222
0.1
4
380
1.2
-0.1
-3
80
100
92
165
TYP
MAX
28
90
4
1.26
0.5
5
440
1.7
-1
-10
Units
V
µA
mA
V
µA
A
KHz
V
µA
µA
mΩ
%
%
°C
YB1683 Rev.1.0
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3
YB1683
3A 380KHz 28V PWM Buck DC/DC Converter
Typical Performance Characteristics
Efficiency V.S Load (Vin=12V)
100%
System Efficiency(%)
90%
80%
70%
60%
50%
0
0.5
1
1.5
2
2.5
3
Output Load Current(A)
2.5V
3.3V
5V
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
(V
IN
– V
GS
)
approximately – 0.5V, with a duty cycle of
approximately V
OUT
/ V
IN
. 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 V
IN
to GND.
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