参数资料
型号: LTC3728IUH#PBF
厂商: Linear Technology
文件页数: 20/36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: 590kHz
占空比: 99%
电源电压: 3.5 V ~ 36 V
降压:
升压:
回扫:
反相:
倍增器:
除法器:
Cuk:
隔离:
工作温度: -40°C ~ 85°C
封装/外壳: 32-WFQFN 裸露焊盘
包装: 管件
LTC3728
APPLICATIONS INFORMATION
factor of (Duty Cycle)/(Ef?ciency). For 5V regulators this
supply means connecting the EXTV CC pin directly to V OUT .
However, for 3.3V and other lower voltage regulators,
additional circuitry is required to derive INTV CC power
from the output.
The following list summarizes the four possible connec-
tions for EXTV CC:
1. EXTV CC Left Open (or Grounded). This will cause INTV CC
to be powered from the internal 5V regulator resulting in
an ef?ciency 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 regulator and provides the highest
ef?ciency.
3. EXTV CC Connected to an External Supply. If an external
supply is available in the 5V to 7V range, it may be used
to power EXTV CC providing it is compatible with the
MOSFET gate drive requirements.
4. EXTV CC Connected to an Output-Derived Boost Network.
For 3.3V and other low voltage regulators, ef?ciency
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 either the inductive
boost winding as shown in Figure 6a or the capacitive
charge pump shown in Figure 6b. The charge pump
has the advantage of simple magnetics.
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 MOS-
FETs. 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 desired MOSFET. This enhances the MOSFET and
turns on the topside switch. 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) .
When adjusting the gate drive level, the ?nal arbiter is the
total input current for the regulator. If a change is made
and the input current decreases, then the ef?ciency has
improved. If there is no change in input current, then there
is no change in ef?ciency.
Output Voltage
The LTC3728 output voltages are each set by an exter-
nal feedback resistive divider carefully placed across
the output capacitor. The resultant feedback signal is
compared with the internal precision 0.800V voltage
OPTIONAL EXTV CC
V IN
V IN
+
1 F
CONNECTION
5V < V SEC < 7V
+
C IN
C IN
+
V IN
V SEC
V IN
BAT85
0.22 F
BAT85
LTC3728
TG1
+
1 F
LTC3728
TG1
VN2222LL
BAT85
R6
EXTV CC
SW
N-CH
T1
1:N
R SENSE
+
V OUT
EXTV CC
SW
N-CH
L1
R SENSE
+
V OUT
R5
FCB
SGND
BG1
PGND
N-CH
C OUT
BG1
PGND
N-CH
C OUT
3728 F06a
Figure 6a. Secondary Output Loop and EXTV CC Connection
Figure 6b. Capacitive Charge Pump for EXTV CC
3728 F06b
3728fg
20
相关PDF资料
PDF描述
VE-J70-EY-F3 CONVERTER MOD DC/DC 5V 50W
VE-J70-EY-F2 CONVERTER MOD DC/DC 5V 50W
LTC3880EUJ#TRPBF IC REG CTRLR BUCK PWM CM 40-QFN
VE-J5K-EY-F3 CONVERTER MOD DC/DC 40V 50W
VE-J5K-EY-F2 CONVERTER MOD DC/DC 40V 50W
相关代理商/技术参数
参数描述
LTC3728LCGN 功能描述:IC REG CTRLR BUCK PWM CM 28-SSOP RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:PolyPhase® 标准包装:4,500 系列:PowerWise® PWM 型:控制器 输出数:1 频率 - 最大:1MHz 占空比:95% 电源电压:2.8 V ~ 5.5 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:-40°C ~ 125°C 封装/外壳:6-WDFN 裸露焊盘 包装:带卷 (TR) 配用:LM1771EVAL-ND - BOARD EVALUATION LM1771 其它名称:LM1771SSDX
LTC3728LCGN#PBF 功能描述:IC REG CTRLR BUCK PWM CM 28-SSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:PolyPhase® 标准包装:4,500 系列:PowerWise® PWM 型:控制器 输出数:1 频率 - 最大:1MHz 占空比:95% 电源电压:2.8 V ~ 5.5 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:-40°C ~ 125°C 封装/外壳:6-WDFN 裸露焊盘 包装:带卷 (TR) 配用:LM1771EVAL-ND - BOARD EVALUATION LM1771 其它名称:LM1771SSDX
LTC3728LCGN#TR 功能描述:IC REG CTRLR BUCK PWM CM 28-SSOP RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:PolyPhase® 标准包装:4,500 系列:PowerWise® PWM 型:控制器 输出数:1 频率 - 最大:1MHz 占空比:95% 电源电压:2.8 V ~ 5.5 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:-40°C ~ 125°C 封装/外壳:6-WDFN 裸露焊盘 包装:带卷 (TR) 配用:LM1771EVAL-ND - BOARD EVALUATION LM1771 其它名称:LM1771SSDX
LTC3728LCGN#TRPBF 功能描述:IC REG CTRLR BUCK PWM CM 28-SSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:PolyPhase® 标准包装:4,500 系列:PowerWise® PWM 型:控制器 输出数:1 频率 - 最大:1MHz 占空比:95% 电源电压:2.8 V ~ 5.5 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:-40°C ~ 125°C 封装/外壳:6-WDFN 裸露焊盘 包装:带卷 (TR) 配用:LM1771EVAL-ND - BOARD EVALUATION LM1771 其它名称:LM1771SSDX
LTC3728LCUH 功能描述:IC REG CTRLR BUCK PWM CM 32-QFN RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:PolyPhase® 标准包装:4,500 系列:PowerWise® PWM 型:控制器 输出数:1 频率 - 最大:1MHz 占空比:95% 电源电压:2.8 V ~ 5.5 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:-40°C ~ 125°C 封装/外壳:6-WDFN 裸露焊盘 包装:带卷 (TR) 配用:LM1771EVAL-ND - BOARD EVALUATION LM1771 其它名称:LM1771SSDX