- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄98002 > LT1307IS8#TR (LINEAR TECHNOLOGY CORP) 1.25 A SWITCHING REGULATOR, 750 kHz SWITCHING FREQ-MAX, PDSO8 PDF資料下載
參數(shù)資料
| 型號： | LT1307IS8#TR |
| 廠商： | LINEAR TECHNOLOGY CORP |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | 1.25 A SWITCHING REGULATOR, 750 kHz SWITCHING FREQ-MAX, PDSO8 |
| 封裝： | 0.150 INCH, PLASTIC, SO-8 |
| 文件頁數(shù)： | 2/20頁 |
| 文件大小： | 369K |
| 代理商： | LT1307IS8#TR |
10
LT1307/LT1307B
1307fa
To eliminate the low frequency noise of Figure 6, the
LT1307 can be replaced with the LT1307B. Figure 9
details the spectral noise at the output of Figure 1’s circuit
using an LT1307B at 5mA load. Although spectral energy
is present at 333kHz due to alternate pulse skipping, all
Burst Mode operation spectral components are gone.
Alternate pulse skipping can be eliminated by increasing
inductance.
FREQUENCY COMPENSATION
Obtaining proper values for the frequency compensation
network is largely an empirical, iterative procedure, since
variations in input and output voltage, topology, capacitor
value and ESR, and inductance make a simple formula
elusive. As an example, consider the case of a 1.25V to
3.3V boost converter supplying 50mA. To determine
optimum compensation, the circuit is built and a transient
load is applied to the circuit. Figure 10 shows the setup.
away from 455kHz. Figure 8 shows the noise spectrum of
the converter with the load increased to 20mA. The
LT1307 shifts out of Burst Mode operation, eliminating
low frequency ripple. Spectral energy is present only at
the switching fundamental and its harmonics. Noise
voltage measures – 5dBmVRMS or 560VRMS at the
575kHz switching frequency, and is below – 60dBmVRMS
for all other frequencies in the range. By combining Burst
Mode with fixed frequency operation, the LT1307 keeps
noise away from 455kHz.
VIN
VOUT
FB
1307 F10
GND
SW
1
F
10
H
MBR0520L
C
R
590k
1M
50
66
3300
1.25V
VC
10
F*
*CERAMIC
SHDN
LT1307
Figure 10. Boost Converter with Simulated Load
Figure 11a details transient response without compensa-
tion components. Although the output ripple voltage at a
1mA load is low, allowing the error amplifier to operate
wideband results in excessive ripple at a 50mA load. Some
kind of loop stabilizing network is obviously required. A
100k/22nF series RC is connected to the VC pin, resulting
in the response pictured in Figure 11b. The output settles
in about 7ms to 8ms. This may be acceptable, but we can
do better. Reducing C to 2nF gives Figure 11c’s response.
This is clearly in the right direction. After another order of
magnitude reduction, Figure 11d’s response shows some
FREQUENCY (kHz)
205
OUTPUT
VOLTAGE
NOISE
(dBmV
RMS
)
0
–10
–20
–30
–40
–50
–60
–70
–80
–90
–100
LT1307 F09
455
705
Figure 9. LT1307B at 5mA Load Shows No Audio Components
or Sidebands About Switching Frequency, 333kHz
Fundamental Amplitude is –10dBmV, or 316
VRMS
FREQUENCY (kHz)
255
OUTPUT
NOISE
VOLTAGE
(dBmV
RMS
)
0
–10
–20
–30
–40
–50
–60
–70
–80
–90
–100
455
1307 F08
655
RBW = 100Hz
Figure 8. With Converter Delivering 20mA, Low Frequency
Sidebands Disappear. Noise is Present Only at the 575kHz
Switching Frequency
APPLICATIO S I FOR ATIO
WU
UU
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| LT1508ISW#TR | POWER FACTOR CONTROLLER WITH POST REGULATOR, 115 kHz SWITCHING FREQ-MAX, PDSO20 |
| LT1513IT7-2#PBF | 5.4 A BATTERY CHARGE CONTROLLER, 580 kHz SWITCHING FREQ-MAX, PSFM7 |
| LT1513IR-2#PBF | 5.4 A BATTERY CHARGE CONTROLLER, 580 kHz SWITCHING FREQ-MAX, PSSO7 |
| LT1640LCS8#TRPBF | 1-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO8 |
| LT1932ES6#PBF | 0.78 A SWITCHING REGULATOR, 1600 kHz SWITCHING FREQ-MAX, PDSO6 |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LT1308 | 制造商:LINER 制造商全稱:Linear Technology 功能描述:Single Cell High Current Micropower 600kHz Boost DC/DC Converter |
| LT1308A | 制造商:LINER 制造商全稱:Linear Technology 功能描述:High Current, Micropower Single Cell, 600kHz DC/DC Converters |
| LT1308A_1 | 制造商:LINER 制造商全稱:Linear Technology 功能描述:High Current, Micropower Single Cell, 600kHz DC/DC Converters |
| LT1308ACF | 功能描述:IC REG BOOST 5V 1A 14TSSOP 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:20 系列:SIMPLE SWITCHER® 類型:降壓（降壓） 輸出類型:固定 輸出數(shù):1 輸出電壓:12V 輸入電壓:4 V ~ 60 V PWM 型:電壓模式 頻率 - 開關(guān):52kHz 電流 - 輸出:1A 同步整流器:無 工作溫度:-40°C ~ 125°C 安裝類型:通孔 封裝/外殼:16-DIP（0.300"，7.62mm） 包裝:管件 供應(yīng)商設(shè)備封裝:16-DIP 其它名稱:*LM2575HVN-12LM2575HVN-12 |
| LT1308ACF#PBF | 功能描述:IC REG BOOST 5V 1A 14TSSOP 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:20 系列:SIMPLE SWITCHER® 類型:降壓（降壓） 輸出類型:固定 輸出數(shù):1 輸出電壓:12V 輸入電壓:4 V ~ 60 V PWM 型:電壓模式 頻率 - 開關(guān):52kHz 電流 - 輸出:1A 同步整流器:無 工作溫度:-40°C ~ 125°C 安裝類型:通孔 封裝/外殼:16-DIP（0.300"，7.62mm） 包裝:管件 供應(yīng)商設(shè)備封裝:16-DIP 其它名稱:*LM2575HVN-12LM2575HVN-12 |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。