WD3125
WD3125
High Efficiency, 40V Step-Up White LED
Driver
Descriptions
The WD3125 is a constant current, high efficiency LED
driver. Internal MOSFET can drive up to 10 white LEDs
in series and 3S9P LEDs with 1.2A current limit and
40V OVP. A Pulse-Width-Modulation (PWM) signal can
be applied to the EN pin for LED dimming. The device
operates with 1MHz fixed switching frequency to
reduce output ripple, improve conversion efficiency,
and allows to use small external components.
LX 1
6 VIN
Http//:www.sh-willsemi.com
SOT-23-6L/TSOT-23-6L
The WD3125 is available in SOT-23-6L package and
TSOT-23-6L Package. Standard product is Pb-free and
Halogen-free.
GND 2
5 OVP
Features
Input voltage range
Open LED Protection
Reference Voltage
Switching frequency
Efficiency
Main switch current limit
PWM Dimming frequency
: 3~5.5V
: 43V (Typ.)
: 300mV (±5%)
: 1MHz (Typ.)
: Up to 92%
: 1.2A (Typ.)
: (5KHz to200KHz)
1
6
FB 3
4 EN
Pin configuration (Top view)
5
4
6
5
4
3125
YYWW
2
3
1
3125
FCYW
2
3
Applications
Smart Phones
Tablets
Portable games
3125 = Device code
YY = Year code
WW = Week code
SOT-23-6L
3125 = Device code
FC = Package Code
Y
W
= Year code
= Week code
TSOT-23-6L
Marking
Order information
Device
WD3125E-6/TR
WD3125F-6/TR
Package
SOT-23-6L
TSOT-23-6L
Shipping
3000/Reel&Tape
3000/Reel&Tape
Will Semiconductor Ltd.
1
Sep, 2014 - Rev. 1.2
WD3125
Typical applications
VIN
CIN
2.2μF
VIN
LX
L1
10 μH
D1
WSB5503W
10-Series
LED
COUT
50V/1μF
EN
WD3125
OVP
GND
FB
RSET
VIN
CIN
2.2μF
VIN
L1
22 μH
D1
WSB5503W
10-Series
LED
COUT
50V/2.2μF
LX
EN
WD3125
OVP
GND
FB
RSET
VIN
CIN
2.2μF
L1
10μH
D1
WSB5503W
COUT
50V/2.2μF
5S2P or
6S2P
LEDs
VIN
LX
EN
WD3125
OVP
GND
FB
RSET
Will Semiconductor Ltd.
2
Sep, 2014 - Rev. 1.2
WD3125
Pin descriptions
Symbol
LX
GND
FB
EN
OVP
VIN
Pin No.
1
2
3
4
5
6
Descriptions
Switch Pin. Connect this Pin to inductor and schottky diode.
Minimize the trace area to reduce EMI.
Ground Pin.
Feedback Pin. Sense the WLED current feedback voltage to set
the current rating.
Enable Pin, Active High. Apply a PWM signal at EN Pin for WLED
brightness dimming.
OVP Pin, Connect to VOUT. Voltage sensing input to trigger the
function of over voltage protection.
Power Supply Pin.
Block diagram
OVP
OVP
PWM
COMP
Current
Sense
Gate
Driver
LX
VIN
UVLO
PWM
Logic
Chip Enable
I
SENSE
OCP
1.2A
OSC
1MHz
FB
EA
V
REF
Bandgap
Reference
GND
EN
PWM
Dimming
Soft
Start
Thermal
Shutdown
Will Semiconductor Ltd.
3
Sep, 2014 - Rev. 1.2
WD3125
Absolute maximum ratings
Parameter
VIN pin voltage range
OVP pin voltage range
EN pin voltage range
LX pin voltage range (DC)
Power Dissipation – SOT-23-6L (Note 1)
Power Dissipation – SOT-23-6L (Note 2)
Junction to Ambient Thermal Resistance – SOT-23-6L (Note 1)
Junction to Ambient Thermal Resistance – SOT-23-6L (Note 2)
Symbol
V
IN
V
OVP
-
-
P
D
R
θJA
T
J
T
L
Topr
Tstg
Value
-0.3½6.5
-0.3½46
-0.3½V
IN
-0.3½46
0.5
0.3
250
416
150
260
-40 ~ 85
-55 ~ 150
Unit
V
V
V
V
W
W
o
o
C/W
C/W
o
o
o
o
Junction temperature
Lead temperature(Soldering, 10s)
Operation temperature
Storage temperature
C
C
C
C
These are stress ratings only. Stresses exceeding the range specified under “Absolute Maximum Ratings”
may cause substantial damage to the device. Functional operation of this device at other conditions beyond
those listed in the specification is not implied and prolonged exposure to extreme conditions may affect device
reliability.
Note 1:
Surface mounted on FR-4 Board using 1 square inch pad size, dual side, 1oz copper
Note 2:
Surface mounted on FR-4 board using minimum pad size, 1oz copper
Will Semiconductor Ltd.
4
Sep, 2014 - Rev. 1.2
WD3125
Electronics Characteristics
(Ta=25
o
C, V
IN
=3.7V, V
EN
=V
IN
, C
IN
=C
OUT
=1uF, unless otherwise noted)
Parameter
Operation Voltage Range
Under Voltage Lockout
Over-Voltage Threshold
UVLO Hysteresis
Quiescent Current
Supply Current
Shutdown Current
Operation Frequency
Maximum Duty Cycle
PWM Dimming Clock Rate
PWM Dimming Duty Cycle
Feedback Reference
On Resistance
Current Limit
EN Threshold Voltage
EN Sink Current
Thermal Shutdown Temperature
T
SD
Hysteresis
Shutdown Delay
V
REF
R
ON
I
LIM
V
ENL
V
ENH
I
EN
T
SD
T
SD-HYS
t
SHDN
1.5
3
160
30
1
I
LX
=100mA
Symbol
V
IN
V
UVLO
V
OVP
V
UVLO-HYS
I
Q
I
S
I
SD
f
OSC
D
MAX
Recommended
No Switching
Switching
V
EN
< 0.4V
0.8
90
5
4
285
300
0.5
1.2
0.4
1
92
200
100
315
V
IN
Rising
Test Condition
Min
3
1.8
40
Typ
--
2.2
43
0.1
0.3
1.5
1
3
1
1.2
Max
5.5
2.5
46
Units
V
V
V
V
mA
mA
μA
MHz
%
KHz
%
mV
Ω
A
V
V
μA
°
C
°
C
ms
Will Semiconductor Ltd.
5
Sep, 2014 - Rev. 1.2
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