- 您现在的位置：买卖IC网 > PDF目录15228 > LTC3890MPUH#PBF (Linear Technology)IC REG CTRLR BUCK PWM CM 32-QFN PDF资料下载
参数资料
| 型号： | LTC3890MPUH#PBF |
| 厂商： | Linear Technology |
| 文件页数： | 22/40页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BUCK PWM CM 32-QFN |
| 标准包装： | 73 |
| 系列： | PolyPhase® |
| PWM 型： | 电流模式 |
| 输出数： | 2 |
| 频率 - 最大： | 850kHz |
| 占空比： | 99% |
| 电源电压： | 4 V ~ 60 V |
| 降压： | 是 |
| 升压： | 无 |
| 回扫： | 无 |
| 反相： | 无 |
| 倍增器： | 无 |
| 除法器： | 无 |
| Cuk： | 无 |
| 隔离： | 无 |
| 工作温度： | -55°C ~ 150°C |
| 封装/外壳： | 32-WFQFN 裸露焊盘 |
| 包装： | 管件 |
第1页第2页第3页第4页第5页第6页第7页第8页第9页第10页第11页第12页第13页第14页第15页第16页第17页第18页第19页第20页第21页当前第22页第23页第24页第25页第26页第27页第28页第29页第30页第31页第32页第33页第34页第35页第36页第37页第38页第39页第40页
LTC3890
APPLICATIONS INFORMATION
The following list summarizes the four possible connec-
tions for EXTV CC :
1. EXTV CC Grounded. This will cause INTV CC to be powered
from the internal 5.1V regulator resulting in an efficiency
penalty of up to 10% at high input voltages.
2. EXTV CC Connected Directly to V OUT . This is the normal
connection for a 5V to 14V regulator and provides the
highest efficiency.
3. EXTV CC Connected to an External Supply. If an external
supply is available in the 5V to 14V range, it may be
used to power EXTV CC providing it is compatible with the
MOSFET gate drive requirements. Ensure that EXTV CC
< V IN .
4. EXTV CC Connected to an Output-Derived Boost Network.
For 3.3V and other low voltage regulators, efficiency
gains can still be realized by connecting EXTV CC 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 EXTV CC < V IN .
desired MOSFET. This enhances the top MOSFET switch
and turns it on. The switch node voltage, SW, rises to V IN
and the BOOST pin follows. With the topside MOSFET
on, the boost voltage is above the input supply: V BOOST =
V IN + V INTVCC . The value of the boost capacitor, C B , needs
to be 100 times that of the total input capacitance of the
topside MOSFET(s). The reverse breakdown of the external
Schottky diode must be greater than V IN(MAX) .
The external diode D B can be a Schottky diode or silicon
diode, but in either case it should have low-leakage and
fast recovery. Pay close attention to the reverse leakage
current specification for this diode, especially at high
temperatures where it generally increases substantially.
For applications with output voltages greater than ~5V
that are switching infrequently, a leaky diode D B can fully
discharge the bootstrap capacitor C B , creating a current
path from the output voltage to the BOOST pin to INTV CC .
Not only does this increase the quiescent current of the
converter, but it can cause INTV CC to rise to dangerous
levels if the leakage exceeds the current consumption on
INTV CC .
C IN
V IN
TG1
1/2 LTC3890
EXTV CC SW
MTOP
MBOT
BAT85
L
NDS7002
R SENSE
BAT85
BAT85
V OUT
Particularly, this is a concern in Burst Mode operation at
no load or very light loads, where the part is switching
very infrequently and the current draw on INTV CC is very
low (typically about 35μA). Generally, pulse-skipping and
forced continuous modes are less sensitive to leakage,
since the more frequent switching keeps the bootstrap
capacitor C B charged, preventing a current path from the
output voltage to INTV CC .
PGND
BG1 C OUT
3890 F09
Figure 9. Capacitive Charge Pump for EXTV CC
Topside MOSFET Driver Supply (C B , D B )
External bootstrap capacitors, C B , connected to the BOOST
pins supply the gate drive voltages for the topside MOSFETs.
Capacitor C B in the Functional Diagram is charged though
external diode D B from INTV CC when the SW pin is low.
When one of the topside MOSFETs is to be turned on, the
driver places the C B voltage across the gate-source of the
However, in cases where the converter has been operat-
ing (in any mode) and then is shut down, if the leakage
of diode D B fully discharges the bootstrap capacitor C B
before the output voltage discharges to below ~5V, then
the leakage current path can be created from the output
voltage to INTV CC . In shutdown, the INTV CC pin is able to
sink about 30μA. To accommodate diode leakage greater
than this amount in shutdown, INTV CC can be loaded
with an external resistor or clamped with a Zener diode.
Alternatively, the PGOOD resistor can be used to sink the
current (assuming the resistor pulls up to INTV CC ) since
PGOOD is pulled low when the converter is shut down.
Nonetheless, using a low-leakage diode is the best choice
to maintain low quiescent current under all conditions.
3890fc
22
相关PDF资料 |
PDF描述 |
|---|---|
| ELL-6PV330M | COIL PWR CHOKE 33UH 600MA SMD |
| ELL-6PV270M | COIL PWR CHOKE 27UH 670MA SMD |
| ELL-6PV220M | COIL PWR CHOKE 22UH 700MA SMD |
| ELL-6PV180M | COIL PWR CHOKE 18UH 840MA SMD |
| ELL-6PV150M | COIL PWR CHOKE 15UH 880MA SMD |
相关代理商/技术参数 |
参数描述 |
|---|---|
| LTC3891EFE#PBF | 功能描述:IC REG CTRLR BUCK PWM CM 20TSSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 特色产品:LM3753/54 Scalable 2-Phase Synchronous Buck Controllers 标准包装:1 系列:PowerWise® PWM 型:电压模式 输出数:1 频率 - 最大:1MHz 占空比:81% 电源电压:4.5 V ~ 18 V 降压:是 升压:无 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-5°C ~ 125°C 封装/外壳:32-WFQFN 裸露焊盘 包装:Digi-Reel® 产品目录页面:1303 (CN2011-ZH PDF) 其它名称:LM3754SQDKR |
| LTC3891EFE#PBF | 制造商:Linear Technology 功能描述:IC DC-DC CONV 900kHz TSSOP20 |
| LTC3891EFE#TRPBF | 功能描述:IC REG CTRLR BUCK PWM CM 20TSSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:500kHz 占空比:96% 电源电压:4 V ~ 36 V 降压:无 升压:是 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-40°C ~ 125°C 封装/外壳:24-WQFN 裸露焊盘 包装:带卷 (TR) |
| LTC3891EUDC#PBF | 功能描述:IC REG CTRLR BUCK PWM CM 20-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 特色产品:LM3753/54 Scalable 2-Phase Synchronous Buck Controllers 标准包装:1 系列:PowerWise® PWM 型:电压模式 输出数:1 频率 - 最大:1MHz 占空比:81% 电源电压:4.5 V ~ 18 V 降压:是 升压:无 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-5°C ~ 125°C 封装/外壳:32-WFQFN 裸露焊盘 包装:Digi-Reel® 产品目录页面:1303 (CN2011-ZH PDF) 其它名称:LM3754SQDKR |
| LTC3891EUDC#PBF | 制造商:Linear Technology 功能描述:IC DC-DC CONV 900kHz QFN20 |
发布紧急采购，3分钟左右您将得到回复。