L4978 Datasheet, PDF (6/12 Pages) STMicroelectronics – 2A STEP DOWN SWITCHING REGULATOR

L4978
Figure 3. Quiescent drain current vs. input
voltage.
Iq
(mA)
5
200KHz
R₁=22K
C₂=1.2nF
D97IN724
100KHz
4
R₁=20K
C₂=2.7nF
3
0Hz
2
1
0
Tamb=25°C
0% DC
5 10 15 20 25 30 35 40 45 50
Vcc(V)
Figure 5. Stand by drain current vs. input
voltage
Ibias
(µA)
D97IN732
150
Vss=GND
140
Tj=25°C
130
120
110
100
Tj=125°C
90
80
70
60
0 5 10 15 20 25 30 35 40 45 50 V_CC(V)
Figure 7. Load regulation
V_O
(V)
3.378
D98IN835
V_CC=35V
3.376
3.374
3.372
3.370
3.368
Tj=125°C
Tj=25°C
3.366
3.364
3.362
3.360
0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 I_O(A)
6/12
Figure 4. Quiescent current vs. junction
temperature
Iq
(mA)
D97IN731
200KHz
5
R₁=22K
C₂=1.2nF
4
3
V_CC=35V
2
0% DC
100KHz
R₁=20K
C₂=2.7nF
0Hz
1
-50 -30 -10 10 30 50 70 90 110 Tj(°C)
Figure 6. Line Regulation
V_O
(V)
3.377
3.376
D97IN733
Tj=125°C
3.375
3.374
Tj=25°C
3.373
3.372
3.371
3.370
0 5 10 15 20 25 30 35 40 45 50 V_CC(V)
Figure 8. Switching frquency vs. R1 and C2
fsw
(KHz)
500
200
100
50
20
10
D97IN784
Tamb=25°C
0.82nF
1.2nF
2.2nF
3.3nF
4.7nF
5.6nF
5
0
20
40
60
80 R1(KΩ)