L4978 STMicroelectronics, L4978 Datasheet - Page 6

• Manufacturer Part Number: L4978
• Description: IC REG SW 2A STEP DOWN 8-DIP
• Manufacturer: STMicroelectronics
• Type: Step-Down (Buck)r

Specifications of L4978

• Internal Switch(s): Yes
• Synchronous Rectifier: No
• Number Of Outputs: 1
• Voltage - Output: 3.3 ~ 50 V
• Current - Output: 2A
• Frequency - Switching: 100kHz ~ 300kHz
• Voltage - Input: 8 ~ 55 V
• Operating Temperature: -40°C ~ 150°C
• Mounting Type: Through Hole
• Package / Case: 8-DIP (0.300", 7.62mm)
• Power - Output: 1W
• Output Voltage: 50 V
• Output Current: 2 A
• Input Voltage: 8 V to 55 V
• Switching Frequency: 90 KHz to 110 KHz
• Operating Temperature Range: - 40 C to + 150 C
• Mounting Style: Through Hole
• Duty Cycle (max): 97 %
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 497-6701-5; E-L4978; E-L4978; L4978

L4978
Figure 6. Quiescent drain current vs. input
voltage.
Figure 7. Quiescent current vs. junction
temperature
Figure 8. Stand by drain current vs. input
voltage.
6/13
(mA)
Ibias
(mA)
(µA)
150
140
130
120
110
100
Iq
5
4
3
2
1
90
80
70
60
Iq
5
4
3
2
1
-50 -30 -10 10 30 50 70 90 110 Tj(˚C)
0 5 10 15 20 25 30 35 40 45 50
0 5 10 15 20 25 30 35 40 45 50 V
Vss=GND
V
0% DC
CC
Tamb=25˚C
0% DC
=35V
200KHz
R
C
1
2
=22K
=1.2nF
Tj=25˚C
100KHz
R
C
1
2
Tj=125˚C
=20K
=2.7nF
200KHz
R
C
100KHz
R
C
0Hz
1
2
1
2
=22K
=1.2nF
=20K
=2.7nF
0Hz
D97IN724
D97IN732
D97IN731
Vcc(V)
CC
(V)
Figure 9. Line Regulation
.
Figure 10. Load regulation
.
Figure 11. Switching frquency vs. R1 and C2
.
(KHz)
3.378
3.376
3.374
3.372
3.370
3.368
3.366
3.364
3.362
3.360
3.377
3.376
3.375
3.374
3.373
3.372
3.371
3.370
500
200
100
fsw
50
20
10
V
(V)
V
(V)
5
O
O
0
0 0.2 0.4 0.6
0 5 10 15 20 25 30 35 40 45 50 V
20
Tj=125˚C
0.8
40
1.0 1.2 1.4 1.6
Tj=25˚C
Tj=125˚C
60
V
Tj=25˚C
CC
Tamb=25˚C
=35V
80
D98IN835
D97IN784
D97IN733
1.8
R1(KΩ)
CC
I
O
(V)
(A)