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參數(shù)資料
| 型號： | LT1432CN8 |
| 廠商： | LINEAR TECHNOLOGY CORP |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | 5V High Efficiency Step-Down Switching Regulator Controller |
| 中文描述： | SWITCHING CONTROLLER, PDIP8 |
| 封裝： | PLASTIC, DIP-8 |
| 文件頁數(shù)： | 14/28頁 |
| 文件大?。?/td> | 611K |
| 代理商： | LT1432CN8 |
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14
LT1432
because these traces do not have errors caused by plating
operations. The suggested trace width for 1/2oz foil is
0.03" for each 1A of current limit to keep trace temperature
rise reasonable. 3A current limit would require the width
to be 0.09". 1oz foil can reduce trace width to 0.02" per
amp. Inductance in the trace is not critical so the trace can
be wound serpentine or any other shape that fits available
space. Kelvin connections should be used as shown in
Figure 14 to avoid errors due to termination resistance.
The length of the sense resistor trace can be calculated
from:
Length=W R
R
Inches
SENSE
CU
)
W = width of copper trace (
≈
0.03" per amp for 1/2oz
copper foil)
R
CU
= resistivity of PCB trace, expressed as
per square.
It is found by calculating the resistance of a section of trace
with equal length and width. For typical 1/2oz material,
R
CU
is approximately 1m
per square. In the example
shown above, with width = 2A times 0.03" = 0.06";
U
S
A
O
PPLICATI
U
U
Figure 15. Adding Foldback Current Limiting
Current limiting maintains true switching action, but power
dissipation in the IC switch and catch diode will shift
depending on output voltage. At output voltages near the
correct regulated value, power will be distributed between
switch and the diode according to the usual calculations.
Under short circuit conditions, switch duty cycle will drop
to a very low value, and power will concentrate in the
diode, which will be running at near 100% duty cycle. If
continuous shorts must be tolerated, the catch diode must
be sized to handle the full current limit value, or foldback
current can be used.
Foldback Current Limiting
Foldback current limiting makes the short circuit current
limit somewhat lower than the full load current limit to
reduce component stress under short circuit conditions.
This is shown in Figure 15 with the addition of R3 and R4.
The voltage drop across R3 adds to the 60mV current limit
+
V
SW
FB
GND
V
IN
V
C
LT1271
+
C1
200
μ
F
35V
C6
0.02
μ
F
C4
0.1
μ
F
R1
680
C5
0.03
μ
F
D1
MBR330p
C3
4.7
μ
F
TANT
D2
1N4148
L1
50
μ
H
R2
0.025
C2
470
μ
F
16V
V
OUT
5V
3A
+
×
220pF
<0.3V = NORMAL MODE
>2.5V = SHUTDOWN
OPEN = BURST MODE
V
IN
6V – 25V
LT1432 F15
R3
100
R4
12.5k
V
C
V
IN
MODE
V
OUT
V
LIM
V
+
LT1432
GND
OPTIONAL
OUTPUT
FILTER
100
μ
F
16V
10
μ
H
3A
+
DIODE
Length=0.06 0.02
0.001
=1.2 Inches
)
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PDF描述 |
|---|---|
| LT1432CN8-3.3 | RADIATION HARDENED HIGH EFFICIENCY, 5 AMP SWITCHING REGULATORS |
| LT1432CS8 | 5V High Efficiency Step-Down Switching Regulator Controller |
| LT1432CS8-3.3 | RADIATION HARDENED HIGH EFFICIENCY, 5 AMP SWITCHING REGULATORS |
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LT1432CN8-3.3 | 功能描述:IC REG CTRLR BUCK PWM 8-DIP RoHS:否 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 標準包裝:4,000 系列:- PWM 型:電壓模式 輸出數(shù):1 頻率 - 最大:1.5MHz 占空比:66.7% 電源電壓:4.75 V ~ 5.25 V 降壓:是 升壓:無 回掃:無 反相:無 倍增器:無 除法器:無 Cuk:無 隔離:無 工作溫度:-40°C ~ 85°C 封裝/外殼:40-VFQFN 裸露焊盤 包裝:帶卷 (TR) |
| LT1432CS8 | 制造商:Linear Technology 功能描述: |
| LT1432CS8-3.3 | 制造商:LINER 制造商全稱:Linear Technology 功能描述:3.3V High Efficiency Step-Down Switching Regulator Controller |
| LT1435 | 制造商:LINER 制造商全稱:Linear Technology 功能描述:4.5A, 500kHz Step-Down Switching Regulator |
| LT1436 | 制造商:LINER 制造商全稱:Linear Technology 功能描述:4.5A, 500kHz Step-Down Switching Regulator |
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