- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄377718 > LT1933 (Linear Technology Corporation) RADIATION HARDENED HIGH EFFICIENCY, 5 AMP SWITCHING REGULATORS PDF資料下載
參數(shù)資料
| 型號(hào)： | LT1933 |
| 廠商： | Linear Technology Corporation |
| 元件分類： | 基準(zhǔn)電壓源/電流源 |
| 英文描述： | RADIATION HARDENED HIGH EFFICIENCY, 5 AMP SWITCHING REGULATORS |
| 中文描述： | 抗輻射高效，5安培開關(guān)穩(wěn)壓器 |
| 文件頁(yè)數(shù)： | 13/16頁(yè) |
| 文件大小： | 629K |
| 代理商： | LT1933 |
第1頁(yè)第2頁(yè)第3頁(yè)第4頁(yè)第5頁(yè)第6頁(yè)第7頁(yè)第8頁(yè)第9頁(yè)第10頁(yè)第11頁(yè)第12頁(yè)當(dāng)前第13頁(yè)第14頁(yè)第15頁(yè)第16頁(yè)
13
LT1933
1933f
APPLICATIU
2.2
μ
F ceramic capacitor at the input. The input voltage
rings as high as 35V and the input current peaks at 20A.
One method of damping the tank circuit is to add another
capacitor with a series resistor to the circuit. In Figure 6b
an aluminum electrolytic capacitor has been added. This
capacitor’s high equivalent series resistance damps the
circuit and eliminates the voltage overshoot. The extra
capacitor improves low frequency ripple filtering and can
slightly improve the efficiency of the circuit, though it is
likely to be the largest component in the circuit. An
alternative solution is shown in Figure 6c. A 1
resistor is
added in series with the input to eliminate the voltage
overshoot (it also reduces the peak input current). A 0.1
μ
F
capacitor improves high frequency filtering. This solution
is smaller and less expensive than the electrolytic capaci-
tor. For high input voltages its impact on efficiency is
minor, reducing efficiency less than one half percent for a
5V output at full load operating from 24V.
W
U
U
Figure 7. Model for Loop Response
–
+
–
+
1.245V
SW
V
C
LT1933
GND
1933 F07
R1
OUT
ESR
ERROR
AMPLIFIER
500k
CURRENT MODE
POWER STAGE
FB
R2
R
C
100k
C
C
80pF
C1
C1
g
m
=
150
μ
mhos
g
m
+
C
PL
0.7V
1.1mho
Frequency Compensation
The LT1933 uses current mode control to regulate the
output. This simplifies loop compensation. In particular,
the LT1933 does not require the ESR of the output
capacitor for stability allowing the use of ceramic capaci-
tors to achieve low output ripple and small circuit size.
Figure 7 shows an equivalent circuit for the LT1933
control loop. The error amp is a transconductance ampli-
fier with finite output impedance. The power section,
consisting of the modulator, power switch and inductor, is
modeled as a transconductance amplifier generating an
output current proportional to the voltage at the V
C
node.
Note that the output capacitor integrates this current, and
that the capacitor on the V
C
node (C
C
) integrates the error
amplifier output current, resulting in two poles in the loop.
R
C
provides a zero. With the recommended output capaci-
tor, the loop crossover occurs above the R
C
C
C
zero. This
simple model works well as long as the value of the
inductor is not too high and the loop crossover frequency
is much lower than the switching frequency. With a larger
ceramic capacitor (very low ESR), crossover may be lower
and a phase lead capacitor (C
PL
) across the feedback
divider may improve the phase margin and transient
response. Large electrolytic capacitors may have an ESR
large enough to create an additional zero, and the phase
lead may not be necessary.
If the output capacitor is different than the recommended
capacitor, stability should be checked across all operating
conditions, including load current, input voltage and tem-
perature. The LT1375 data sheet contains a more thor-
ough discussion of loop compensation and describes how
to test the stability using a transient load.
PCB Layout
For proper operation and minimum EMI, care must be
taken during printed circuit board layout. Figure 8 shows
the recommended component placement with trace,
ground plane and via locations. Note that large, switched
currents flow in the LT1933’s V
IN
and SW pins, the catch
diode (D1) and the input capacitor (C2). The loop formed
by these components should be as small as possible and
tied to system ground in only one place. These compo-
nents, along with the inductor and output capacitor,
SHUTDOWN
VIAS TO LOCAL GROUND PLANE
OUTLINE OF LOCAL GROUND PLANE
V
IN
V
OUT
SYSTEM
GROUND
1933 F08
C2
D1
C1
Figure 8. A Good PCB Layout Ensures Proper, Low EMI Operation
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| LT1934ES6-1 | RADIATION HARDENED HIGH EFFICIENCY, 5 AMP SWITCHING REGULATORS |
| LT1934IS6 | RADIATION HARDENED HIGH EFFICIENCY, 5 AMP SWITCHING REGULATORS |
| LT1934IS6-1 | RADIATION HARDENED HIGH EFFICIENCY, 5 AMP SWITCHING REGULATORS |
| LT1934-1 | RADIATION HARDENED HIGH EFFICIENCY, 5 AMP SWITCHING REGULATORS |
| LT1934 | RADIATION HARDENED HIGH EFFICIENCY, 5 AMP SWITCHING REGULATORS |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LT1933_1 | 制造商:LINER 制造商全稱:Linear Technology 功能描述:600mA, 500kHz Step-Down Switching Regulator in SOT-23 and DFN Packages |
| LT1933ES6 | 制造商:Linear Technology 功能描述:Conv DC-DC Single Step Down 3.6V to 36V 6-Pin TSOT-23 |
| LT1933ES6#PBF | 制造商:Linear Technology 功能描述:IC STEP-DOWN REGULATOR 6-TSOT-23 |
| LT1933ES6#TR | 功能描述:IC REG BUCK ADJ 0.6A TSOT23-6 RoHS:否 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 開關(guān)穩(wěn)壓器 系列:- 標(biāo)準(zhǔn)包裝:2,500 系列:- 類型:升壓（升壓） 輸出類型:可調(diào)式 輸出數(shù):1 輸出電壓:1.24 V ~ 30 V 輸入電壓:1.5 V ~ 12 V PWM 型:電流模式，混合 頻率 - 開關(guān):600kHz 電流 - 輸出:500mA 同步整流器:無(wú) 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:8-SOIC（0.154"，3.90mm 寬） 包裝:帶卷 (TR) 供應(yīng)商設(shè)備封裝:8-SOIC |
| LT1933ES6#TRM | 功能描述:IC REG BUCK ADJ 0.6A TSOT23-6 RoHS:否 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 開關(guān)穩(wěn)壓器 系列:- 標(biāo)準(zhǔn)包裝:2,500 系列:- 類型:升壓（升壓） 輸出類型:可調(diào)式 輸出數(shù):1 輸出電壓:1.24 V ~ 30 V 輸入電壓:1.5 V ~ 12 V PWM 型:電流模式，混合 頻率 - 開關(guān):600kHz 電流 - 輸出:500mA 同步整流器:無(wú) 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:8-SOIC（0.154"，3.90mm 寬） 包裝:帶卷 (TR) 供應(yīng)商設(shè)備封裝:8-SOIC |
發(fā)布緊急采購(gòu)，3分鐘左右您將得到回復(fù)。