L4971 STMicroelectronics, L4971 Datasheet - Page 7

• Manufacturer Part Number: L4971
• Description: IC REG SW 1.5A STEP DOWN 8-DIP
• Manufacturer: STMicroelectronics
• Type: Step-Down (Buck)r

Specifications of L4971

• Internal Switch(s): Yes
• Synchronous Rectifier: No
• Number Of Outputs: 1
• Voltage - Output: 3.3 ~ 50 V
• Current - Output: 1.5A
• Frequency - Switching: 100kHz ~ 300kHz
• Voltage - Input: 8 ~ 55 V
• Operating Temperature: 0°C ~ 125°C
• Mounting Type: Through Hole
• Package / Case: 8-DIP (0.300", 7.62mm)
• Power - Output: 1W
• Output Voltage: 50 V
• Mounting Style: Through Hole
• For Use With: 497-4744 - BOARD EVAL FOR L4971/L4978 REG
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 497-6697-5; E-L4971; E-L4971; L4971

Figure 12. Switching Frequency vs. input
Figure 13. Switching frequency vs. junction
Figure 14. Dropout voltage between pin 5 and 4
(KHz)
(KHz)
107.5
105.0
102.5
100.0
fsw
(V)
0.5
0.4
0.3
0.2
0.1
0.0
∆
97.5
95.0
92.5
90.0
105
100
fsw
95
90
V
-50
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 I
0 5 10 15 20 25 30 35 40 45 50 V
voltage.
temperature.
0
50
Tj=25˚C
Tj=125˚C
100
Tj=-25˚C
D97IN736
D97IN735
D97IN785
CC
Tj(˚C)
O
(A)
(V)
Figure 15. Efficiency vs output voltage.
Figure 16. Efficiency vs. output current.
Figure 17. Efficiency vs. output current.
(%)
(%)
(%)
96
94
92
90
88
86
84
82
90
85
80
75
70
65
60
90
85
80
75
70
65
60
η
η
η
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 I
0
0
V
V
CC
0.2 0.4 0.6 0.8 1.0 1.2 1.4 I
CC
=24V
=12V
5
V
CC
V
CC
=48V
10
V
V
=12V
CC
CC
=48V
=24V
V
100KHz
15
CC
=8V
200KHz
20
fsw=100KHz
V
fsw=100KHz
V
V
O
O
V
I
CC
=5.1V
O
=3.36V
CC
=1.5A
=8V
=35V
25
D97IN738
D97IN739
D97IN737
V
O
O
O
(A)
(A)
(V)
L4971
7/13