LM3557 Datasheet, PDF (7/19 Pages) National Semiconductor (TI) – Step-Up Converter for White LED Applications

LM3557
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SNVS338B – NOVEMBER 2004 – REVISED FEBRUARY 2013
TYPICAL PERFORMANCE CHARACTERISTICS (continued)
( Circuit in Figure 1: L = DO1608C-223, D = SS16, and LED = LWT67C. Efficiency: η = P_OUT/P_IN = [(V_OUT – V_Fb) * I_OUT]/[V_IN *
I_IN]. T_A= 25°C, unless otherwise stated).
R_Sw2(Figure 3: N2) vs TEMPERATURE
ENABLE THRESHOLD vs TEMPERATURE
12
0.9
V_IN = 3.6V
V_IN = 2.7V
10
V_IN = 3V
V_IN = 4.2V
0.8
0.7
ON
8
0.6
6
V_IN = 4.2V
0.5
OFF
0.4
4
0.3
0.2
2
0.1
0
-40
25
85
0
-40
27
70
85
TEMPERATURE (°C)
Figure 10.
TEMPERATURE (°C)
Figure 11.
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