Typical Performance Characteristics (Continued)
85
80
75
70
65
60
70
56
42
28
14
0
1.6 1.7 1.8 1.9 2.0 2.1 2.2 2.3 2.4
-40 -25 -10
5
20 35 50 65 80 95 110 125
VFB (V)
Temperature (°C)
Figure 14. Normal PWM Frequency (fOSC
)
Figure 15. PWM Frequency vs. FB Voltage
vs. Temperature
0.90
0.82
0.74
0.66
0.58
0.90
0.85
0.80
0.75
0.70
0.65
0.60
0.50
0.7 0.9 1.1 1.3 1.5 1.7 1.9 2.1 2.3 2.5 2.7 2.9 3.1 3.3
0.7 0.9 1.1 1.3 1.5 1.7 1.9 2.1 2.3 2.5 2.7 2.9 3.1 3.3
VIN (V)
VIN ( V )
Figure 16. Current-Limit Threshold vs. VIN Voltage
Figure 17. 2/3 Current-Limit Threshold vs. VIN Voltage
71.0
70.5
70.0
69.5
69.0
68.5
1.4
1.2
1.0
0.8
0.6
0.4
-40 -25 -10
5
20 35 50 65 80 95 110 125
-40 -25 -10
5
20 35 50 65 80 95 110 125
Temperature (℃)
Temperature (℃)
Figure 18. Output Current of RT Pin (IRT
vs. Temperature
)
Figure 19. FB Output High Voltage (VRTTH
)
vs. Temperature
© 2008 Fairchild Semiconductor Corporation
SG6846A • Rev. 1.1.4
www.fairchildsemi.com
10
FAIRCHILD [ FAIRCHILD SEMICONDUCTOR ]
