L4978 STMicroelectronics, L4978 Datasheet - Page 8

• 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 18. Efficiency vs. output current.
.
Figure 19. Efficiency vs. output current.
.
Figure 20. Efficiency vs. Vcc.
.
8/13
(%)
(%)
90
85
80
75
70
65
60
90
85
80
75
70
65
60
55
η
η
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 I
90
85
80
75
70
n [%]
0
0
0.2 0.4 0.6 0.8 1.0 1.2 1.4 I
10
Vo=5.1V fsw=200kHz
Vo=3.36V fsw=200kHz
Io=2A
V
V
CC
V
CC
20
CC
V
=12V
=12V
V
CC
=48V
CC
V
=24V
Vo=3.36V fsw=100kHz
Vcc [V]
V
CC
=24V
CC
30
=48V
Vo=5.1V fsw=100kHz
=8V
V
40
CC
fsw=200KHz
V
fsw=200KHz
V
O
=8V
O
=5.1V
=3.36V
50
D97IN740
D97IN741
60
O
O
(A)
(A)
Figure 21. Power dissipation vs. Vcc.
.
Figure 22. Device Power dissipation vs. Vo
.
Figure 23. Pulse by pulse limiting current vs.
junction temperature..
Ilim
(A)
2.9
2.8
2.7
2.6
2.5
2.4
2.3
1000
-50 -25
Pdiss [mW]
800
600
400
200
1400
1200
1000
Pdiss [mW]
800
600
400
200
0
0
0
0
Vcc=35V
fsw=100kHz
Vo=5.1V
fsw=100kHz
10
0
fsw=100KHz
V
10
CC
20
25
=35V
Vcc [V]
Io=1.5A
Vo [V]
50
30
20
Io=2A
75 100 125 Tj(˚C)
Io=1.5A
40
Io=2A
Io=0.5A
Io=0.5A
Io=1A
50
30
Io=1A
D97IN747
60