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PDF L4976 Data sheet ( Hoja de datos )
| Número de pieza | L4976 | |
| Descripción | 1A STEP DOWN SWITCHING REGULATOR | |
| Fabricantes | STMicroelectronics | |
| Logotipo |  |
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Hay una vista previa y un enlace de descarga de L4976 (archivo pdf) en la parte inferior de esta página. Total 11 Páginas | ||
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® L4976
1A STEP DOWN SWITCHING REGULATOR
UP TO 1A STEP DOWN CONVERTER
OPERATING INPUT VOLTAGE FROM 8V TO
55V
PRECISE 5.1V REFERENCE VOLTAGE
OUTPUT VOLTAGE ADJUSTABLE FROM
3.3V TO 50V
SWITCHING FREQUENCY ADJUSTABLE UP
TO 500KHz
VOLTAGE FEEDFORWARD
ZERO LOAD CURRENT OPERATION
INTERNAL CURRENT LIMITING (PULSE-BY-
PULSE AND HICCUP MODE)
PROTECTION AGAINST FEEDBACK DIS-
CONNECTION
THERMAL SHUTDOWN
DESCRIPTION
The L4976 is a step down monolithic power
switching regulator delivering 1A at a voltage be-
tween 3.3V and 50V (selected by a simple exter-
nal divider). Realized in BCD mixed technology,
the device uses an internal power D-MOS transis-
tor (with a typical Rdson of 0.25Ω) to obtain very
high efficency and high switching speed.
A switching frequency up to 250KHz is achiev-
able (the maximum power dissipation of the pack-
TYPICAL APPLICATION CIRCUIT
Minidip
SO16W
ORDERING NUMBERS: L4976 (Minidip)
L4976D (SO16)
ages must be observed).
A wide input voltage range between 8V to 55V
and output voltages regulated from 3.3V to 40V
cover the majority of today’s applications.
Features of this new generations of DC-DC con-
verter include pulse-by-pulse current limit, hiccup
mode for short circuit protection, voltage feedfor-
ward regulation, protection against feedback loop
disconnection and thermal shutdown.
The device is available in plastic dual in line,
MINIDIP 8 for standard assembly, and SO16W
for SMD assembly.
Vi=8V to 55V
5
8
R1
20K L4976
3
4
C1 C7
220µF 220nF
C2
2.7nF
2
7
16
63V
L1
260µH
(77120)
VO=3.3V/1A
R2
9.1K
C4
22nF
C6
100nF
D1
GI
SB360
C8
330µF
May 2000
1/11
1 page  
Figure 1. 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 3. Line Regulation
VO
(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 VCC(V)
Figure 5. Switching frquency vs. R1 and C2
fsw
(KHz)
500
D97IN784
Tamb=25°C
200
100
50
20
10
0.82nF
1.2nF
2.2nF
3.3nF
4.7nF
5.6nF
5
0
20 40 60 80 R1(KΩ)
L4976
Figure 2. Quiescent current vs. junction
temperature
Iq
(mA)
D97IN731
200KHz
5 R1=22K
C2=1.2nF
4
3
VCC=35V
2 0% DC
100KHz
R1=20K
C2=2.7nF
0Hz
1
-50 -30 -10 10 30 50 70 90 110 Tj(°C)
Figure 4. Load regulation
VO
(V)
3.378
3.376
3.374
3.372
3.370
3.368
3.366
3.364
3.362
3.360
0
D97IN734
VCC=35V
Tj=25°C
Tj=125°C
0.2 0.4 0.6 0.8 1.0 1.2 1.4 IO(A)
Figure 6. Switching Frequency vs. input
voltage.
fsw
(KHz)
D97IN735
107.5
105.0
102.5
Tj=25°C
100.0
97.5
95.0
92.5
90.0
0 5 10 15 20 25 30 35 40 45 50 VCC(V)
5/11
5 Page 
L4976
Information furnished is believed to be accurate and reliable. However, STMicroelectroni cs assumes no responsibility for the consequences
of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is
granted by implication or otherwise under any patent or patent rights of STMicroelectronics. Specification mentioned in this publication are
subject to change without notice. This publication supersedes and replaces all information previously supplied. STMicroelectronics products
are not authorized for use as critical components in life support devices or systems without express written approval of STMicroelectronics.
The ST logo is a registered trademark of STMicroelectronics
© 2000 STMicroelectronics GROUP OF COMPANIES
Australia - Brazil - China - Finland - France - Germany - Hong Kong - India - Italy - Japan - Malaysia - Malta - Morocco -
Singapore - Spain - Sweden - Switzerland - United Kingdom - U.S.A.
http://www.st.com
11/11
11 Page | ||
| Páginas | Total 11 Páginas | |
| PDF Descargar | [ Datasheet L4976.PDF ] | |
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