Data Sheet
WHITE LED DRIVER
General Description
The AP3008 is a 1.2MHz PWM boost switching regu-
lator designed for constant-current white LED driver
applications.
The AP3008 can drive a string of 2 to 3 white LEDs
from a 2.7V supply in series, ensuring uniform bright-
ness and eliminating several ballast resistors. The
AP3008 implements a constant frequency 1.2MHz
PWM control scheme. The high frequency PWM oper-
ation also saves board space by reducing external com-
ponent sizes. To improve efficiency, the feedback
voltage is set to 95 mV, which reduces the power
dissipation in the current setting resistor.
The AP3008 is equipped with OVP protection ability,
the SW pin monitors the output voltage and will turn
off the device if an over-voltage condition is present to
prevent damage from an open circuit condition.
The AP3008 is available in SOT-23-5 package.
AP3008
Features
·
·
·
·
·
·
·
·
Inherently Uniform LED Current
High Efficiency up to 84%
Drives 2 to 3 LEDs from a 2.7V Supply
1.2MHz PWM Operation Frequency
Requires Only 0.22
µ
F Output Capacitor
Shutdown Current: <1
µ
A
Built-in Output Over-Voltage Protection
Under Voltage Lock Out (UVLO)
Applications
·
·
·
·
·
Digital Cameras
LCD modules
GPS Receivers
Cellular Phones
PDAs, Handheld Computers
SOT-23-5
Figure 1. Package Type of AP3008
Aug. 2008 Rev. 1. 5
1
BCD Semiconductor Manufacturing Limited
Data Sheet
WHITE LED DRIVER
Pin Configuration
K Package
(SOT-23-5)
AP3008
SW
GND
FB
1
2
3
5
V
IN
4
SHDN
Figure 2. Pin Configuration of AP3008 (Top View)
Pin Description
Pin Number
1
Pin Name
SW
Function
Switch Pin. Connect inductor/diode here. The output voltage can range up to 29V but not
extend this limit. If the voltage on this pin is higher than the overvoltage protection thre-
shold (OVP), the device comes back to shutdown mode. To restart the chip, one must then
send a low to high sequence on shutdown pin or switch off the V
IN
supply.
Ground Pin.
Voltage Feedback. Reference voltage is 95mV.
Shutdown Pin. Connect to 1.5V or higher to enable device;
Connect to 0.4V or less to disable device.
Input Supply Pin. Must be locally bypassed.
2
3
4
5
GND
FB
SHDN
V
IN
Aug. 2008 Rev. 1. 5
2
BCD Semiconductor Manufacturing Limited
Data Sheet
WHITE LED DRIVER
Functional Block Diagram
AP3008
OVP
1
DRIVER
SW
FB
V
IN
3
5
V
REF
1.25V
95mV
A1
A2
COMPARATOR
R
S
Q
Q1
Σ
2
SHDN
4
GND
SHUTDOWN
RAMP
GENERATOR
1.2MHz
OSCILLATOR
Figure 3. Functional Block Diagram of AP3008
Ordering Information
AP3008
Circuit Type
Package
K: SOT-23-5
-
E1: Lead Free
G1: Green
TR: Tape and Reel
Package
SOT-23-5
Temperature
Range
-40 to 85
o
C
Part Number
Lead Free
AP3008KTR-E1
Marking ID
Lead Free
E1B
Green
AP3008KTR-G1
Green
G1B
Packing
Type
Tape & Reel
BCD Semiconductor's Pb-free products, as designated with "E1" suffix in the part number, are RoHS compliant. Products with
"G1" suffix are available in green packages.
Aug. 2008 Rev. 1. 5
3
BCD Semiconductor Manufacturing Limited
Data Sheet
WHITE LED DRIVER
Absolute Maximum Ratings (Note 1)
Parameter
Input Voltage
SW Voltage
FB Voltage
SHDN Voltage
Thermal Resistance (Junction to Atmosphere, no Heat sink)
Operating Junction Temperature
Storage Temperature Range
Lead Temperature (Soldering, 10sec)
ESD (Machine Model)
ESD (Human Body Model)
T
STG
T
LEAD
R
θJA
Symbol
V
IN
Value
15
36
10
15
265
150
-65 to 150
260
250
2000
Unit
V
V
V
V
o
C/W
o
C
o
o
AP3008
C
C
V
V
Note 1:
Stresses greater than those listed under "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 indi-
cated under "Recommended Operating Conditions" is not implied. Exposure to "Absolute Maximum Ratings" for extended
periods may affect device reliability.
Recommended Operating Conditions
Parameter
Operating Temperature Range
Operating Voltage Range
Symbol
T
OP
Min
-40
2.5
Max
85
12
Unit
o
C
V
Aug. 2008 Rev. 1. 5
4
BCD Semiconductor Manufacturing Limited
Data Sheet
WHITE LED DRIVER
Electrical Characteristics
(V
IN
=3V, V
SHDN
=3V, T
A
=25
o
C, unless otherwise specified.)
Parameter
Feedback Voltage
FB Pin Bias Current
Supply Current
Supply Current
Switch Frequency
Maximum Duty Cycle
Switch Current Limit
Switch VCESAT
Switch Leakage Current
V
TH
SHDN Voltage
SHDN Pin Bias Current
OVP Voltage
V
OVP
V
TL
I
CC
I
Q
f
D
MAX
I
LIM
V
CESAT
Duty=15%
I
SW
=250mA
V
SW
=5V
High
Low
50
29
1.5
0.4
V
µA
V
V
SHDN
=V
IN
, V
FB
=V
IN
, No switching
V
SHDN
=0V
0.8
85
Symbol
V
FB
Conditions
I
SW
=100mA, Duty Cycle=66%
Min
86
Typ
95
45
1.9
0.1
1.2
90
320
350
0.01
5
Max
104
100
2.5
1.0
1.6
Unit
mV
nA
mA
µA
MHz
%
mA
mV
µA
AP3008
Aug. 2008 Rev. 1. 5
5
BCD Semiconductor Manufacturing Limited
