TC2574 Datasheet, PDF (22/25 Pages) TelCom Semiconductor, Inc – 0.5A Step-Down Switching Regulator

0.5A Step-Down Switching Regulator
TC2574
TYPICAL CHARACTERISTICS (Circuit of Figure 2 Cont.)
Figure 29. Oscillator Frequency
8.0
6.0
VIN = 12 V
4.0
Normalized at 25°C
2.0
0
–2.0
–4.0
–6.0
–8.0
10
–50 –25
0
25
50
75 100 125
TJ JUNCTION TEMPERATURE (°C)
Figure 30. Switch Saturation Voltage
1.3
1.2
1.1
1.0
0.9 –40°C
0.8
25°C
0.7
0.6
125°C
0.5
0.4
0.3
0
0.1
0.2
0.3
0.4
0.5
SWITCH CURRENT (A)
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
±50
Figure 31. Minimum Operating Voltage
Adjustable Version Only
VIN = 1.23V
ILOAD = 100mA
±25
0
25
50
75 100 125
TJ JUNCTION TEMPERATURE (°C)
100
80
60
40
20
0
–20
–0
–60
–80
–100
–50
Figure 32. Feedback Pin Current
Adjustable Version Only
–25
0
25
50
75 100 125
TJ, JUNCTION TEMPERATURE (5C)
Figure 33. Continuous Mode Switching Waveforms
VOUT = 5.0V, 500mA Load Current, L = 330µH
20V
A _10V
0
0.6A
B ^0.4A
0.2A
0
C
20mV
AC
5 µsec/DIV
A: Output Pin Voltage 10V/DIV.
B: Inductor Current, 0.2 A/DI.V.
C: Output Ripple Voltage, 20mV/DIV, AC-Coupled
Figure 34. Discontinuous Mode Switching Waveforms
VOUT = 5.0V, 100mA Load Current, L = 100µH
20V
A _10V
0
0.6A
B _0.4A
0.2A
0
C
20mV
AC
5 µsec/DIV
A: Output Pin Voltage 10V/DIV.
B: Inductor Current, 0.2 A/DI.V.
C: Output Ripple Voltage, 20mV/DIV, AC-Coupled
TC2574-1 1/6/00
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