SAMHOP Microelectronics Corp.
8-BIT CONSTANT CURRENT LED DRIVER
Output Current - Duty (LED turn-on rate)
Output Current - REXT Resistor
Ta - P
D
R
EXT - IOUT
1.6
1.4
1.2
100
90
80
P FREE AIR
≒
I
OUT
{(1.25 / REXT (Ω)} ×14.7
70
60
50
40
30
20
1
0.8
0.6
0.4
0.2
0
F/FN ON PCB
V
OUT = 0.7V
DD = 5.0V
V
F/FN FREE AIR
10
0
200 300
500
1,000
2,000 3,000 5,000
-40 -20
0
80
20
40
60
Ambient Temerature Ta (oC)
Fig. 1
REXT (Ω)
Output Current - Output Voltage
Vce-Ice
0.09
0.08
0.07
0.06
0.05
R=240Ω
R=470Ω
0.04
Ice
0.03
0.02
0.01
R=3900Ω
0
-0.01
0
0.5
1
1.5
2
2.5
3
3.5
Vce
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V.2.10