SD42351
350MA WHITE SINGLE LED DRIVER
DESCRIPTION
The SD42351 is a low dropout current regulator rated for constant LED
sink current. The low quiescent current and low dropout voltage is
achieved by advanced Bi-CMOS process.
FEATURES
* No external component required.
* Fixed 110mA, 150 mA, 170 mA, 215 mA, 245mA, 270mA, 305mA,
335mA sink current.
* Output short / open circuit protection.
* Low dropout voltage.
* Low quiescent current
* Build-in thermal protection
* Supply voltage range 3V ~ 6V
* 2KV HBM ESD protection
* Advanced Bi-CMOS process.
SOT-89-3
APPLICATIONS
* 1W Power LED driver
ORDERING INFORMATION
Package
Type
SD42351NA
SD42351NB
SD42351NC
SOT-89-3
SD42351ND
SD42351NE
SD42351NG
SD42351NH
SD42351NL
Seal
351A
351B
351C
351D
351E
351G
351H
351L
Current Value (Typical) (mA)
335
305
270
245
215
170
150
110
HANGZHOU SILAN MICROELECTRONICS CO.,LTD
Http: //www.silan.com.cn
REV:1.5
2008.03.13
Page 1 of 5
SD42351
BLOCK DIAGRAM
ABSOLUTE MAXIMUM RATINGS
(T
amb
=25°C)
Characteristics
Max Supply Voltage
Min Supply Voltage
Operating Temperature
Storage Temperature
Symbol
V
DD(max)
V
DD(min
)
T
amb
T
st
Rating
6
3
0 ~ + 70
-40 ~ +150
Unit
V
V
°C
°C
ELECTRICAL CHARACTERISTICS
(Unless otherwise specified, T
amb
=25°C, I
OUT
=335mA)
Characteristics
Supply Voltage Range
Quiescent Current
Output Current
Current Line Regulation
Dropout Voltage
Power NMOS Leakage
Thermal Shut-down Temp
Shut-down Temp Hysteresis
Symbol
V
DD
I
Q
I
OUT
ΔI
OUT
ΔV
IN
* I
OUT
Test
--
--
3V≤V
IN
≤6V
3V≤V
IN
≤6V
condition
Min.
3
--
320
--
--
--
--
--
Typ.
--
160
335
2.08
120
0.1
140
20
Max.
6
200
350
--
--
1
--
--
Unit
V
uA
mA
%/V
mV
μA
°C
°C
Vd
ropout
I
leak
T
j(sd)
T
hyst
I=335mA,Measured at V
OUT
V
OUT
＝5V
--
--
HANGZHOU SILAN MICROELECTRONICS CO.,LTD
Http: //www.silan.com.cn
REV:1.5
2008.03.13
Page 2 of 5
SD42351
PIN CONFIGURATION
PIN DESCRIPTION
Pin No.
1
2
3
Pin Name
V
OUT
GND
V
DD
I/O
O
--
I
LED Current Output.
Ground .
Power Supply.
Pin Description
FUNCTION DESCRIPTION
The SD42351 is a low dropout current regulator rated for constant LED sink current. The low quiescent current
and low dropout voltage is achieved by advanced Bi-CMOS process. Its main function is to stabilize the current
passing, other than the LED voltage. Traditional LED drivers are Voltage regulator IC, which will affect the
brightness because of different forward voltages, although the LEDs are in the same structure. SD42351 controls
the brightness of the LED by controlling the current passing by the LED, which eliminates the limitation of
traditional voltage regulator IC.
The device consists of Voltage Reference, Error Amplifier, Power NMOS, Current Sense Resistance, LOGIC
Enable and Over Temperature Protection Circuit. The resistance senses the output current and transform to the
voltage, which compared with the reference voltage. The error is amplified, controls the Power NMOS, so that the
output current is regulated.
Inrush current (over 1 A) in traditional LED drivers is eliminated by the initial current limit circuit, thus constant
sink current in the LED is maintained.
TYPICAL APPLICATION CIRCUIT
Note:The circuit and parameters are reference only, please set the parameters of the real application circuit
based on the real test .
HANGZHOU SILAN MICROELECTRONICS CO.,LTD
Http: //www.silan.com.cn
REV:1.5
2008.03.13
Page 3 of 5
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