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부품번호 | L4976D 기능 |
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기능 | 1A STEP DOWN SWITCHING REGULATOR | ||
제조업체 | STMicroelectronics | ||
로고 | |||
전체 11 페이지수
® 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
L4976
ELECTRICAL CHARACTERISTICS (continued)
Symbol
Parameter
Reference Section
Reference Voltage
Line Regulation
Load Regulation
Short Circuit Current
Test Condition
Iref = 0 to 10mA;
VCC = 8 to 55V
Iref = 0mA;
VCC = 8 to 55V
Vref = 0 to 5mA;
VCC = 0 to 20mA
DC Characteristics
Iqop Total operating quiescent
current
Iq Quiescent current
Error Amplifier
VFB Voltage Feedback Input
RL Line regulation
Ref. voltage stability vs
temperature
VoH High level output voltage
VoL Low level output voltage
Io source Source output current
Io sink
Sink output current
Ib Source bias current
SVRR E/A Supply voltage ripple rejection
DC open loop gain
gm Transconductance
Oscillator Section
Ramp Valley
Ramp peak
Maximum duty cycle
Maximum Frequency
Duty Cycle = 0; VFB = 3.8V
Vcc = 8 to 55V
VFB = 2.5V
VFB = 3.8V
Vcomp = 6V; VFB = 2.5V
Vcomp = 6V; VFB = 3.8V
Vcomp = Vfb; Vcc = 8 to 55V
RL = ∞
Icomp = -0.1 to 0.1mA
Vcomp = 6V
Vcc = 8V
Vcc = 55V
Duty Cycle = 0%
Rosc = 13kΩ, Cosc = 820pF
Min. Typ. Max. Unit
5.0 5.1 5.2 V
* 4.950 5.1 5.250 V
5 10 mV
2 10 mV
6 25 mV
30 65 100 mA
4 6 mA
2.5 3.5 mA
3.33
*
3.36
5
0.4
3.39
10
V
mV
mV/°C
10.3 V
0.65 V
180 220
µA
200 300
µA
2 3 µA
60 80
dB
50 57
dB
2.5 ms
0.78 0.85 0.92
V
2 2.15 2.3 V
9
9.6 10.2
V
95 97
%
500 kHz
4/11
4페이지 Figure 13. Efficiencyvs. output current.
η
(%)
D97IN741
90 VCC=8V
85 VCC=12V
80 VCC=24V
75
70
VCC=48V
65 fsw=200KHz
VO=3.36V
60
55
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 IO(A)
Figure 15. Power dissipation vs. Vcc.
Pdiss
(mW)
800
D97IN743
VO=5.1V
fsw=100KHz
600
IO=1.5A
IO=1A
400
IO=0.5A
200
0
0
10 20 30 40 50 VCC(V)
Figure 17. Pulse by pulse limiting current vs.
junction temperature.
Ilim D97IN747
(A)
fsw=100KHz
2.9 VCC=35V
2.8
2.7
2.6
2.5
2.4
2.3
-50 -25 0 25 50 75 100 125 Tj(°C)
L4976
Figure 14. Efficiencyvs. Vcc.
η D97IN742
(%)
V0=5.1V-fSW=100KHz
85 V0=5.1V-fSW =200KHz
80
75
IO=1.5A
V
0
=3V.03=6V3.-3fS6WV=-1fS2W00=K1H0z0KHz
70
0
10 20 30 40 50 VCC(V)
Figure 16. Efficiencyvs. Vo.
Pdiss
(mW)
800
600
VCC=35V
fsw=100KHz
D97IN744
IO=1.5A
IO=1A
400
IO=0.5A
200
0
0
5 10 15 20 25 30 V0(V)
Figure 18. Load transient.
7/11
7페이지 | |||
구 성 | 총 11 페이지수 | ||
다운로드 | [ L4976D.PDF 데이터시트 ] |
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부품번호 | 상세설명 및 기능 | 제조사 |
L4976 | 1A STEP DOWN SWITCHING REGULATOR | STMicroelectronics |
L4976D | 1A STEP DOWN SWITCHING REGULATOR | STMicroelectronics |
DataSheet.kr | 2020 | 연락처 | 링크모음 | 검색 | 사이트맵 |