- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄39425 > LTC3859EFE#PBF (LINEAR TECHNOLOGY CORP) SWITCHING CONTROLLER, 900 kHz SWITCHING FREQ-MAX, PDSO38 PDF資料下載
參數(shù)資料
| 型號： | LTC3859EFE#PBF |
| 廠商： | LINEAR TECHNOLOGY CORP |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | SWITCHING CONTROLLER, 900 kHz SWITCHING FREQ-MAX, PDSO38 |
| 封裝： | 4.40 MM, LEAD FREE, PLASTIC, TSSOP-38 |
| 文件頁數(shù)： | 20/42頁 |
| 文件大?。?/td> | 624K |
| 代理商： | LTC3859EFE#PBF |
第1頁第2頁第3頁第4頁第5頁第6頁第7頁第8頁第9頁第10頁第11頁第12頁第13頁第14頁第15頁第16頁第17頁第18頁第19頁當(dāng)前第20頁第21頁第22頁第23頁第24頁第25頁第26頁第27頁第28頁第29頁第30頁第31頁第32頁第33頁第34頁第35頁第36頁第37頁第38頁第39頁第40頁第41頁第42頁
LTC3859
27
3859fa
APPLICATIONS INFORMATION
To prevent the maximum junction temperature from being
exceeded, the input supply current must be checked while
operating in continuous conduction mode (PLLIN/MODE
= INTVCC) at maximum VIN.
When the voltage applied to EXTVCC rises above 4.7V, the
VBIAS LDO is turned off and the EXTVCC LDO is enabled.
The EXTVCC LDO remains on as long as the voltage applied
to EXTVCC remains above 4.5V. The EXTVCC LDO attempts
to regulate the INTVCC voltage to 5.4V, so while EXTVCC
is less than 5.4V, the LDO is in dropout and the INTVCC
voltage is approximately equal to EXTVCC. When EXTVCC
is greater than 5.4V, up to an absolute maximum of 14V,
INTVCC is regulated to 5.4V.
Using the EXTVCC LDO allows the MOSFET driver and
control power to be derived from one of the LTC3859’s
switching regulator outputs (4.7V ≤ VOUT ≤ 14V) dur-
ing normal operation and from the VBIAS LDO when the
output is out of regulation (e.g., startup, short-circuit). If
more current is required through the EXTVCC LDO than
is specied, an external Schottky diode can be added
between the EXTVCC and INTVCC pins. In this case, do
not apply more than 6V to the EXTVCC pin and make sure
than EXTVCC ≤ VBIAS.
Signicant efciency and thermal gains can be realized
by powering INTVCC from the buck output, since the VIN
current resulting from the driver and control currents will
be scaled by a factor of (Duty Cycle)/(Switcher Efciency).
For 5V to 14V regulator outputs, this means connecting
the EXTVCC pin directly to VOUT. Tying the EXTVCC pin to
a 8.5V supply reduces the junction temperature in the
previous example from 125°C to:
TJ = 70°C + (40mA)(8.5V)(34°C/W) = 82°C
However, for 3.3V and other low voltage outputs, addi-
tional circuitry is required to derive INTVCC power from
the output.
The following list summarizes the four possible connec-
tions for EXTVCC:
1. EXTVCC left open (or grounded). This will cause INTVCC
to be powered from the internal 5.4V regulator result-
ing in an efciency penalty of up to 10% at high input
voltages.
2. EXTVCC connected directly to the output voltage of one
of the buck regulators. This is the normal connection
for a 5V to 14V regulator and provides the highest ef-
ciency.
3. EXTVCC connected to an external supply. If an external
supply is available in the 5V to 14V range, it may be
used to power EXTVCCprovidingitiscompatiblewiththe
MOSFET gate drive requirements. Ensure that EXTVCC
< VIN.
4. EXTVCC connected to an output-derived boost network
off one of the buck regulators. For 3.3V and other low
voltage buck regulators, efciency gains can still be
realized by connecting EXTVCC to an output-derived
voltage that has been boosted to greater than 4.7V. This
can be done with the capacitive charge pump shown in
Figure 9. Ensure that EXTVCC < VIN.
Figure 9. Capacitive Charge Pump for EXTVCC
3859 F09
LTC3859
TG
SW
BG
PGND
RSENSE
MTOP
MBOT
L
EXTVCC
BAT85
C1
VIN1,2
BAT85
VOUT1,2
Topside MOSFET Driver Supply (CB, DB)
External bootstrap capacitors CB connected to the BOOST
pins supply the gate drive voltages for the topside MOSFETs.
Capacitor CB in the Functional Diagram is charged though
external diode DB from INTVCC when the SW pin is low.
When one of the topside MOSFETs is to be turned on, the
driver places the CB voltage across the gate-source of the
desired MOSFET. This enhances the MOSFET and turns
on the topside switch. The switch node voltage, SW, rises
to VIN for the buck channels (VOUT for the boost channel)
and the BOOST pin follows. With the topside MOSFET
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| LTC3859EFE#TRPBF | SWITCHING CONTROLLER, 900 kHz SWITCHING FREQ-MAX, PDSO38 |
| LTC4160EUDC#PBF | POWER SUPPLY MANAGEMENT CKT, PQCC20 |
| LTC4266IUHF#TRPBF | POWER SUPPLY MANAGEMENT CKT, PQCC38 |
| LTC4266CUHF#PBF | POWER SUPPLY MANAGEMENT CKT, PQCC38 |
| LTC500-4MM | LOW PASS FILTER |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LTC3859EUHF#PBF | 功能描述:IC REG CTRLR BST PWM CM 38-QFN RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 特色產(chǎn)品:LM3753/54 Scalable 2-Phase Synchronous Buck Controllers 標(biāo)準(zhǔn)包裝:1 系列:PowerWise® PWM 型:電壓模式 輸出數(shù):1 頻率 - 最大:1MHz 占空比:81% 電源電壓:4.5 V ~ 18 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:-5°C ~ 125°C 封裝/外殼:32-WFQFN 裸露焊盤 包裝:Digi-Reel® 產(chǎn)品目錄頁面:1303 (CN2011-ZH PDF) 其它名稱:LM3754SQDKR |
| LTC3859EUHF#TRPBF | 功能描述:IC REG CTRLR BST PWM CM 38-QFN RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 標(biāo)準(zhǔn)包裝:4,500 系列:PowerWise® PWM 型:控制器 輸出數(shù):1 頻率 - 最大:1MHz 占空比:95% 電源電壓:2.8 V ~ 5.5 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 ~ 125°C 封裝/外殼:6-WDFN 裸露焊盤 包裝:帶卷 (TR) 配用:LM1771EVAL-ND - BOARD EVALUATION LM1771 其它名稱:LM1771SSDX |
| LTC3859IFE#PBF | 功能描述:IC REG CTRLR BST PWM CM 38-TSSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 標(biāo)準(zhǔn)包裝:4,500 系列:PowerWise® PWM 型:控制器 輸出數(shù):1 頻率 - 最大:1MHz 占空比:95% 電源電壓:2.8 V ~ 5.5 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 ~ 125°C 封裝/外殼:6-WDFN 裸露焊盤 包裝:帶卷 (TR) 配用:LM1771EVAL-ND - BOARD EVALUATION LM1771 其它名稱:LM1771SSDX |
| LTC3859IFE#TRPBF | 功能描述:IC REG CTRLR BST PWM CM 38-TSSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 標(biāo)準(zhǔn)包裝:4,500 系列:PowerWise® PWM 型:控制器 輸出數(shù):1 頻率 - 最大:1MHz 占空比:95% 電源電壓:2.8 V ~ 5.5 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 ~ 125°C 封裝/外殼:6-WDFN 裸露焊盤 包裝:帶卷 (TR) 配用:LM1771EVAL-ND - BOARD EVALUATION LM1771 其它名稱:LM1771SSDX |
| LTC3859IUHF#PBF | 功能描述:IC REG CTRLR BST PWM CM 38VQFN RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 標(biāo)準(zhǔn)包裝:2,000 系列:- PWM 型:電流模式 輸出數(shù):1 頻率 - 最大:1MHz 占空比:50% 電源電壓:9 V ~ 10 V 降壓:無 升壓:是 回掃:是 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:8-TSSOP（0.173"，4.40mm 寬） 包裝:帶卷 (TR) |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。