- 您现在的位置：买卖IC网 > PDF目录80200 > LTC3865IFE#PBF (LINEAR TECHNOLOGY CORP) DUAL SWITCHING CONTROLLER, 880 kHz SWITCHING FREQ-MAX, PDSO38 PDF资料下载
参数资料
| 型号： | LTC3865IFE#PBF |
| 厂商： | LINEAR TECHNOLOGY CORP |
| 元件分类： | 稳压器 |
| 英文描述： | DUAL SWITCHING CONTROLLER, 880 kHz SWITCHING FREQ-MAX, PDSO38 |
| 封装： | 4.40 MM, LEAD FREE, PLASTIC, TSSOP-38 |
| 文件页数： | 11/38页 |
| 文件大小： | 400K |
| 代理商： | LTC3865IFE#PBF |
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页当前第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
LTC3865/LTC3865-1
19
3865fb
APPLICATIONS INFORMATION
which are highest at high input voltages. For VIN < 20V
the high current efciency generally improves with larger
MOSFETs, while for VIN > 20V the transition losses rapidly
increase to the point that the use of a higher RDS(ON) device
with lower CMILLER actually provides higher efciency. The
synchronous MOSFET losses are greatest at high input
voltage when the top switch duty factor is low or during
a short-circuit when the synchronous switch is on close
to 100% of the period.
The term (1 +
δ) is generally given for a MOSFET in the
form of a normalized RDS(ON) vs Temperature curve, but
δ = 0.005/°C can be used as an approximation for low
voltage MOSFETs.
The optional Schottky diodes conduct during the dead time
between the conduction of the two power MOSFETs. These
prevent the body diodes of the bottom MOSFETs from turn-
ing on, storing charge during the dead time and requiring
a reverse recovery period that could cost as much as 3%
in efciency at high VIN. A 1A to 3A Schottky is generally
a good compromise for both regions of operation due to
the relatively small average current. Larger diodes result
in additional transition losses due to their larger junction
capacitance.
Soft-Start and Tracking
The LTC3865/LTC3865-1 have the ability to either soft-start
by themselves with a capacitor or track the output of another
channel or external supply. When one particular channel
is congured to soft-start by itself, a capacitor should be
connected to its TK/SS pin. This channel is in the shutdown
state if its RUN pin voltage is below 1.22V. Its TK/SS pin
is actively pulled to ground in this shutdown state.
Once the RUN pin voltage is above 1.22V, the channel pow-
ers up. A soft-start current of 1.3μA then starts to charge
its soft-start capacitor. Note that soft-start or tracking is
achieved not by limiting the maximum output current of
the controller but by controlling the output ramp voltage
according to the ramp rate on the TK/SS pin. Current
foldback is disabled during this phase to ensure smooth
soft-start or tracking. The soft-start or tracking range is
dened to be the voltage range from 0V to 0.6V on the
TK/SS pin. The total soft-start time can be calculated as:
t
C
A
SOFTSTART
SS
= 06
13
.
μ
Regardless of the mode selected by the MODE/PLLIN pin,
the regulator will always start in pulse-skipping mode
up to TK/SS = 0.5V. Between TK/SS = 0.5V and 0.54V, it
will operate in forced continuous mode and revert to the
selected mode once TK/SS > 0.54V. The output ripple
is minimized during the 40mV forced continuous mode
window ensuring a clean PGOOD signal.
When the channel is congured to track another supply,
the feedback voltage of the other supply is duplicated by
a resistor divider and applied to the TK/SS pin. Therefore,
the voltage ramp rate on this pin is determined by the
ramp rate of the other supply’s voltage. Note that the small
soft-start capacitor charging current is always owing,
producing a small offset error. To minimize this error, select
the tracking resistive divider value to be small enough to
make this error negligible.
In order to track down another channel or supply after
the soft-start phase expires, the LTC3865/LTC3865-1 are
forced into continuous mode of operation as soon as VFB
is below the undervoltage threshold of 0.54V regardless of
the setting on the MODE/PLLIN pin. However, the LTC3865/
LTC3865-1 should always be set in forced continuous
mode tracking down when there is no load. After TK/SS
drops below 0.1V, the corresponding channel will operate
in discontinuous mode.
Output Voltage Tracking
The LTC3865/LTC3865-1 allow the user to program how its
output ramps up and down by means of the TK/SS pins.
Through these pins, the output can be set up to either co-
incidentally or ratiometrically track another supply’s output,
as shown in Figure 5. In the following discussions, VOUT1
refers to the LTC3865/LTC3865-1’s output 1 as a master
channel and VOUT2 refers to the LTC3865/LTC3865-1’s out-
put 2 as a slave channel. In practice, though, either phase
can be used as the master. To implement the coincident
tracking in Figure 5a, connect an additional resistive divider
to VOUT1 and connect its midpoint to the TK/SS pin of the
slave channel. The ratio of this divider should be the same
as that of the slave channel’s internal feedback divider
相关PDF资料 |
PDF描述 |
|---|---|
| LSN-T/10-D12N-C | 1-OUTPUT 51 W DC-DC REG PWR SUPPLY MODULE |
| LM9140AYM-10.0 | 1-OUTPUT TWO TERM VOLTAGE REFERENCE, 10 V, PDSO8 |
| LM285BYZ-2.5X | 1-OUTPUT TWO TERM VOLTAGE REFERENCE, 2.5 V, PBCY3 |
| LS4001-9PD1T | 1-OUTPUT 100 W AC-DC PWR FACTOR CORR MODULE |
| LTC1436AACGN-PLL | SWITCHING CONTROLLER, 400 kHz SWITCHING FREQ-MAX, PDSO24 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| LTC3865IUH#PBF | 功能描述:IC REG CTRLR BUCK PWM CM 32-QFN 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: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) |
| LTC3865IUH#TRPBF | 功能描述:IC REG CTRLR BUCK PWM CM 32-QFN 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: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) |
| LTC3865IUH-1#PBF | 功能描述:IC REG CTRLR BUCK PWM CM 32-QFN 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: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) |
| LTC3865IUH-1#TRPBF | 功能描述:IC REG CTRLR BUCK PWM CM 32-QFN 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: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) |
| LTC3866EFE#PBF | 功能描述:IC REG CTRLR BUCK PWM CM 24TSSOP 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:2,000 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:1MHz 占空比:50% 电源电压:9 V ~ 10 V 降压:无 升压:是 回扫:是 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-40°C ~ 85°C 封装/外壳:8-TSSOP（0.173"，4.40mm 宽） 包装:带卷 (TR) |
发布紧急采购，3分钟左右您将得到回复。