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參數(shù)資料
| 型號： | LT1578 |
| 廠商： | Linear Technology Corporation |
| 英文描述： | 1.5A, 200kHz Step-Down Switching Regulator(1.5A, 200kHz，步降開關(guān)穩(wěn)壓器) |
| 中文描述： | 1.5A的，200kHz降壓型開關(guān)穩(wěn)壓器（1.5A的，200kHz的，步降開關(guān)穩(wěn)壓器） |
| 文件頁數(shù)： | 22/28頁 |
| 文件大?。?/td> | 292K |
| 代理商： | LT1578 |
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LT1578/LT1578-2.5
APPLICATIO
S I
FOR
ATIO
U
How Do I Test Loop Stability
The “standard” compensation for LT1578 is a 100pF
capacitor for C
C
, with R
C
= 0. While this compensation will
work for most applications, the “optimum” value for loop
compensation components depends, to various extents,
on parameters which are not well controlled. These in-
clude inductor value (
±
30% due to production tolerance,
load current and ripple current variations), output capaci-
tance (
±
20% to
±
50% due to production tolerance,
temperature, aging and changes at the load), output
capacitor ESR (
±
200% due to production tolerance,
temperature and aging), and finally, DC input voltage and
output load current. This makes it important for the
designer to check out the final design to ensure that it is
“robust” and tolerant of all these variations.
W
U
U
One way to check switching regulator loop stability is by
pulse loading the regulator output while observing the
transient response at the output, using the circuit shown
in Figure 13. The regulator loop is “hit” with a small
transient AC load current at a relatively low frequency,
50Hz to 1kHz. This causes the output to jump a few
millivolts, then settle back to the original value, as shown
in Figure 14. A well behaved loop will settle back cleanly,
whereas a loop with poor phase or gain margin will “ring”
as it settles. The number of rings indicates the degree of
stability, and the frequency of the ringing shows the
approximate unity-gain frequency of the loop. Amplitude
of the signal is not particularly important, as long as the
amplitude is not so high that the loop behaves nonlinearly.
0.2ms/DIV
1578 F14
10mV/DIV
V
OUT
AT
I
= 500mA
BEFORE FILTER
V
OUT
AT
I
= 500mA
AFTER FILTER
V
OUT
AT
I
= 50mA
AFTER FILTER
LOAD PULSE
THROUGH 50
f
≈
780Hz
5A/DIV
Figure 14. Loop Stability Check
TO
OSCILLOSCOPE
SYNC
100Hz TO 1kHz
100mV TO 1V
P-P
ADJUSTABLE
DC LOAD
ADJUSTABLE
INPUT SUPPLY
100
μ
F TO
1000
μ
F
RIPPLE FILTER
1578 F13
TO X1
OSCILLOSCOPE
PROBE
3300pF
330pF
50
470
4.7k
SWITCHING
REGULATOR
+
Figure 13. Loop Stability Test Circuit
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| LT1579CS-3.3 | 300mA Dual Input Smart Battery Backup Regulator |
| LT1579CS8 | CAP 22UF 80V ELECT TG SMD |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LT1578-2.5 | 制造商:LINER 制造商全稱:Linear Technology 功能描述:1.5A, 200kHz Step-Down Switching Regulator |
| LT1578C | 制造商:LINER 制造商全稱:Linear Technology 功能描述:1.5A, 200kHz Step-Down Switching Regulator |
| LT1578CS8 | 功能描述:IC REG BUCK ADJ 1.5A 8SOIC 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:降壓（降壓） 輸出類型:固定 輸出數(shù):1 輸出電壓:1.2V，1.5V，1.8V，2.5V 輸入電壓:2.7 V ~ 20 V PWM 型:- 頻率 - 開關(guān):- 電流 - 輸出:50mA 同步整流器:是 工作溫度:-40°C ~ 125°C 安裝類型:表面貼裝 封裝/外殼:10-TFSOP，10-MSOP（0.118"，3.00mm 寬）裸露焊盤 包裝:帶卷 (TR) 供應(yīng)商設(shè)備封裝:10-MSOP 裸露焊盤 |
| LT1578CS8#PBF | 功能描述:IC REG BUCK ADJ 1.5A 8SOIC RoHS:是 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:降壓（降壓） 輸出類型:固定 輸出數(shù):1 輸出電壓:1.2V，1.5V，1.8V，2.5V 輸入電壓:2.7 V ~ 20 V PWM 型:- 頻率 - 開關(guān):- 電流 - 輸出:50mA 同步整流器:是 工作溫度:-40°C ~ 125°C 安裝類型:表面貼裝 封裝/外殼:10-TFSOP，10-MSOP（0.118"，3.00mm 寬）裸露焊盤 包裝:帶卷 (TR) 供應(yīng)商設(shè)備封裝:10-MSOP 裸露焊盤 |
| LT1578CS8#TR | 功能描述:IC REG BUCK ADJ 1.5A 8SOIC 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:降壓（降壓） 輸出類型:固定 輸出數(shù):1 輸出電壓:1.2V，1.5V，1.8V，2.5V 輸入電壓:2.7 V ~ 20 V PWM 型:- 頻率 - 開關(guān):- 電流 - 輸出:50mA 同步整流器:是 工作溫度:-40°C ~ 125°C 安裝類型:表面貼裝 封裝/外殼:10-TFSOP，10-MSOP（0.118"，3.00mm 寬）裸露焊盤 包裝:帶卷 (TR) 供應(yīng)商設(shè)備封裝:10-MSOP 裸露焊盤 |
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