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參數(shù)資料
| 型號(hào)： | LT1303CN8-5 |
| 廠商： | LINEAR TECHNOLOGY CORP |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | Micropower High Efficiency DC/DC Converters with Low-Battery Detector Adjustable and Fixed 5V |
| 中文描述： | 0.75 A SWITCHING REGULATOR, 155 kHz SWITCHING FREQ-MAX, PDIP8 |
| 封裝： | 0.300 INCH, PLASTIC, DIP-8 |
| 文件頁(yè)數(shù)： | 6/12頁(yè) |
| 文件大?。?/td> | 280K |
| 代理商： | LT1303CN8-5 |
6
LT1303/LT1303-5
W
IAGRA
BLOCK
S
If switch current reaches 1A, causing C2 to trip, switch on-
time is reduced and off-time increases slightly. This allows
continuous operation during bursts. C2 monitors the
voltage across 3
resistor R1 which is directly related to
the switch current. Q2’s collector current is set by the
emitter-area ratio to 0.6% of Q1’s collector current. When
R1’s voltage drop exceeds 18mV, corresponding to 1A
switch current, C2’s output goes high, truncating the on-
time portion of the oscillator cycle and increasing off-time
OPERATIO
Operation of the LT1303 is best understood by referring to
the Block Diagram in Figure 2. When C1’s negative input,
related to the output voltage by the appropriate resistor-
divider ratio, is higher than the 1.24V reference voltage,
C1’s output is low. C2, A3 and the oscillator are turned off,
drawing no current. Only the reference and C1 consume
current, typically 140
μ
A. When C1’s negative input drops
below 1.24V and overcomes C1’s 6mV hysteresis, C1’s
output goes high, enabling the oscillator, current compara-
tor C2 and driver A3. Quiescent current increases to 2mA
as the device goes into active switching mode. Q1 then
turns on in controlled saturation for nominally 6
μ
s or until
current comparator C2 trips, whichever comes first. The
switch then turns off for approximately 1.5
μ
s, then turns on
again. The LT1303’s switching causes current to alter-
nately build up in L1 and dump into output capacitor C4 via
D1, increasing the output voltage. When the output is high
enough to cause C1’s output to go high, switching action
ceases. Capacitor C4 is left to supply current to the load
until V
OUT
decreases enough to force C1’s output high, and
the entire cycle repeats. Figure 4 details relevant wave-
forms. C1’s cycling causes low-to-mid-frequency ripple
voltage on the output. Ripple can be reduced by making the
U
output capacitor large. The 100
μ
F unit specified results in
ripple of 50mV to 100mV on the 5V output. A 220
μ
F
capacitor will decrease ripple by approximately 50%.
–
+
–
+
–
+
6
7
8
3
2
5
1
4
V
IN
R1
3
Q2
1
×
Q1
160
×
SHUTDOWN
LBO
LBI
GND
PGND
R1
474k
R2
156k
C3
C2
C1
FB
SW
OFF
OSCILLATOR
A3
DRIVER
CURRENT
COMPARATOR
HYSTERETIC
COMPARATOR
REFERENCE
1.24V
18mV
LT1303 BD02
Figure 3. LT1303-5 Block Diagram
20
μ
s/DIV
V
100mV/DIV
AC COUPLED
LT1303 F04
Figure 4. Burst Mode Operation in Action
I
L
1A/DIV
V
5V/DIV
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| LT1303CS8 | Micropower High Efficiency DC/DC Converters with Low-Battery Detector Adjustable and Fixed 5V |
| LT1303CS8-5 | Micropower High Efficiency DC/DC Converters with Low-Battery Detector Adjustable and Fixed 5V |
| LT1304-3.3 | Micropower DC/DC Converters with Low-Battery Detector Active in Shutdown(微功耗,3.3V固定輸出電壓,步升DC/DC變換器(關(guān)斷時(shí)電池低壓檢測(cè)器仍然工作)) |
| LT1304-5 | Micropower DC/DC Converters with Low-Battery Detector Active in Shutdown |
| LT1304 | Micropower DC/DC Converters with Low-Battery Detector Active in Shutdown |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LT1303CN8-5#PBF | 功能描述:IC REG BOOST 5V 0.2A 8DIP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 開(kāi)關(guān)穩(wěn)壓器 系列:- 標(biāo)準(zhǔn)包裝:250 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 輸入電壓:2.05 V ~ 6 V PWM 型:電壓模式 頻率 - 開(kāi)關(guān):2MHz 電流 - 輸出:500mA 同步整流器:是 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:6-UFDFN 包裝:帶卷 (TR) 供應(yīng)商設(shè)備封裝:6-SON（1.45x1） 產(chǎn)品目錄頁(yè)面:1032 (CN2011-ZH PDF) 其它名稱:296-25628-2 |
| LT1303CN8PBF | 制造商:Linear Technology 功能描述:LT1303CN8PBF |
| LT1303CS8 | 功能描述:IC REG BOOST ADJ 0.2A 8SOIC RoHS:否 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 開(kāi)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(kāi)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 |
| LT1303CS8#PBF | 功能描述:IC REG BOOST ADJ 0.2A 8SOIC RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 開(kāi)關(guān)穩(wěn)壓器 系列:- 標(biāo)準(zhǔn)包裝:250 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 輸入電壓:2.05 V ~ 6 V PWM 型:電壓模式 頻率 - 開(kāi)關(guān):2MHz 電流 - 輸出:500mA 同步整流器:是 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:6-UFDFN 包裝:帶卷 (TR) 供應(yīng)商設(shè)備封裝:6-SON（1.45x1） 產(chǎn)品目錄頁(yè)面:1032 (CN2011-ZH PDF) 其它名稱:296-25628-2 |
| LT1303CS8#TR | 功能描述:IC REG BOOST ADJ 0.2A 8SOIC RoHS:否 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 開(kāi)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(kāi)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 |
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