PAM2803 Datasheet, PDF (1/8 Pages) Power Analog Micoelectronics – 3W High Power White LED Driver

PAM2803
3W High Power White LED Driver
Features
General Description
n LED Power Efficiency: up to 90%
n Current Accuracy:±5%(V = _IN 3.6V to 1.8V
@V_F=3.7V)
n Low Start-Up Voltage: 0.9V(I = _LED 270mA)
n Low Hold Voltage:0.75V(I_LED=200mA)
n 1MHz Switching Frequency
n Uses small, Low Profile External Components
n Low RDS(ON) : 100mΩ (TYP.)
n Open LED Protection
n Over Temperature Protection
n Low Profile SOT-23-6 Package
n Pb-Free Package
Applications
n White LED Torch (Flashlight)
n White LED Camera Flash
n DSC(Digital Still Camera)Flash
n Cellular Camera Phone Flash
n PDA Camera Flash
n Camcorder Torch(Flashlight) Lamp
The PAM2803 is a set-up DC-DC converter that
delivers a regulated output current. The device
switches at a 1.0MHz constant frequency,
allowing for the use of small value external
inductor and ceramic capacitors.
The PAM2803 is targeted to be used for driving
loads up to 1A from a two-cell alkaline battery. The
LED current can be programmed by the external
current sense resistor, Rs, connected between the
feedback pin (FB) and ground. A low 95mV
feedback voltage reduces the power loss in the Rs
for better efficiency. With its internal 2A, 100mΩ
NMOS switch, the device can provide high
efficiency even at heavy load. During the
shutdown mode, the feedback resistor Rs and the
load are completely disconnected and the current
consumption is reduced to less than 1uA.
The PAM2803 is available in the 6-lead SOT-23-6
package.
Typical Application
2.2uH
1
SW
6 VIN VOUT ⁵
C_IN
PAM2803
V_IN
10uF
SHDN FB 3
OFF ON ⁴
GND
2
I = _LED 750mA, R_S=0.127Ω
3W
WLED
C_O
R_S
10uF
Block Diagram
95mV
Reference
+
A1
-
FB
VOUT VIN
Comparator
-
Rc ^A2
+
Cc
PWM Logic
And Driver
Σ
Ramp
Generator
SW
+
-
SHDN _Shutdown
And
Soft-start
1.0MHz
Oscillator
GND
Power Analog Microelectronics,Inc
www.poweranalog.com
1
08/2007