- 您现在的位置：买卖IC网 > PDF目录1832 > LTC3838IFE#TRPBF (Linear Technology)IC REG CTRLR BUCK PWM CM 38TSSOP PDF资料下载
参数资料
| 型号： | LTC3838IFE#TRPBF |
| 厂商： | Linear Technology |
| 文件页数： | 15/54页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BUCK PWM CM 38TSSOP |
| 标准包装： | 2,500 |
| 系列： | PolyPhase® |
| PWM 型： | 电流模式 |
| 输出数： | 2 |
| 频率 - 最大： | 2MHz |
| 电源电压： | 4.5 V ~ 38 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： | 38-TFSOP （0.173"，4.40mm 宽）裸露焊盘 |
| 包装： | 带卷 (TR) |
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页当前第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页第39页第40页第41页第42页第43页第44页第45页第46页第47页第48页第49页第50页第51页第52页第53页第54页
LTC3838
OPERATION (Refer to Functional Diagram)
from V IN and can output 5.3V to DRV CC1 . Alternatively,
an internal EXTV CC switch (with on-resistance of around
2Ω) can short the EXTV CC pin to DRV CC2 .
If the EXTV CC pin is below the EXTV CC switchover voltage
(typically 4.6V with 200mV hysteresis, see the Electri-
cal Characteristics Table), then the internal 5.3V LDO is
enabled. If the EXTV CC pin is tied to an external voltage
source greater than this EXTV CC switchover voltage, then
the LDO is shut down and the internal EXTV CC switch
shorts the EXTV CC pin to the DRV CC2 pin, thereby power-
ing DRV CC and INTV CC with the external voltage source
and helping to increase overall efficiency and decrease
internal self heating from power dissipated in the LDO.
This external power source could be the output of the
step-down converter itself (if the output is programmed
to higher than the switchover voltage’s higher limit, 4.8V).
The V IN pin still needs to be powered up but now draws
minimum current.
Power for most internal control circuitry other than gate
drivers is derived from the INTV CC pin. INTV CC can be pow-
ered from the combined DRV CC pins through an external
RC filter to SGND to filter out noises due to switching.
Shutdown and Start-Up
Each of the RUN1 and RUN2 pins has an internal proportion-
al-to-absolute-temperature (PTAT) current source (around
1.2μA at 25°C) to pull up the pins. Taking both RUN1 and
RUN2 pins below a certain threshold voltage (around 0.8V
at 25°C) shuts down all bias of INTV CC and DRV CC and
places the LTC3838 into micropower shutdown mode
with a minimum I Q at the V IN pin. The LTC3838’s DRV CC
(through the internal 5.3V LDO regulator or EXTV CC ) and
the corresponding channel’s internal circuitry off INTV CC
will be biased up when either or both RUN pins are pulled
up above the 0.8V threshold, either by the internal pull-up
current or driven directly by external voltage source such
as logic gate output.
A channel of the LTC3838 will not start switching until the
RUN pin of the respective channel is pulled up to 1.2V.
When a RUN pin rises above 1.2V, the corresponding
channel’s TG and BG drivers are enabled, and TRACK/
SS released. An additional 5μA temperature-independent
pull-up current is connected internally to the channel’s
respective RUN pin. To turn off TG, BG and the addi-
tional 5μA pull-up current, RUN needs to be pulled down
below 1.2V by about 100mV. These built-in current and
voltage hystereses prevent false jittery turn-on and turn-off
due to noise. Such features on the RUN pins allow input
undervoltage lockout (UVLO) to be set up using external
voltage dividers from V IN .
The start-up of a channel’s output voltage (V OUT ) is
controlled by the voltage on its TRACK/SS pin. When the
voltage on the TRACK/SS pin is less than the 0.6V internal
reference, the (differential) feedback voltage is regulated to
the TRACK/SS voltage instead of the 0.6V reference. The
TRACK/SS pin can be used to program the output voltage
soft-start ramp-up time by connecting an external capaci-
tor from a TRACK/SS pin to signal ground. An internal
temperature-independent 1μA pull-up current charges
this capacitor, creating a voltage ramp on the TRACK/SS
pin. As the TRACK/SS voltage rises linearly from ground
to 0.6V, the switching starts, V OUT ramps up smoothly to
its final value and the feedback voltage to 0.6V. TRACK/
SS will keep rising beyond 0.6V, until being clamped to
around 3.7V.
Alternatively, the TRACK/SS pin can be used to track an
external supply like in a master slave configuration. Typi-
cally, this requires connecting a resistor divider from the
master supply to the TRACK/SS pin (see the Applications
Information section).
TRACK/SS is pulled low internally when the correspond-
ing channel’s RUN pin is pulled below the 1.2V threshold
(hysteresis applies), or when INTV CC or either of the
DRV CC1,2 pins drop below their respective undervoltage
lockout (UVLO) thresholds.
Light Load Current Operation
If the MODE/PLLIN pin is tied to INTV CC or an external clock
is applied to MODE/PLLIN, the LTC3838 will be forced to
operate in continuous mode. With load current less than
one-half of the full load peak-to-peak ripple, the inductor
current valley can drop to zero or become negative. This
allows constant-frequency operation but at the cost of low
efficiency at light loads.
3838fa
15
相关PDF资料 |
PDF描述 |
|---|---|
| LTC3839EUH#PBF | IC REG CTRLR BUCK PWM CM 32-QFN |
| LTC3850IGN-2#TRPBF | IC REG CTRLR BUCK PWM CM 28-SSOP |
| LTC3850IGN#PBF | IC REG CTRLR BUCK PWM CM 28-SSOP |
| LTC3851EGN#PBF | IC REG CTRLR BUCK PWM CM 16-SSOP |
| LTC3851EMSE-1#PBF | IC REG CTRLR BUCK PWM CM 16-MSOP |
相关代理商/技术参数 |
参数描述 |
|---|---|
| LTC3838IUHF#PBF | 功能描述:IC REG CTRLR BUCK PWM CM 38-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) |
| LTC3838IUHF#TRPBF | 功能描述:IC REG CTRLR BUCK PWM CM 38-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) |
| LTC3838IUHF-1#PBF | 制造商:Linear Technology 功能描述:IC REG CTRLR BUCK PWM CM 38QFN 制造商:Linear Technology 功能描述:BUCK DUAL CNTRL 4.5-38V 2MHZ 38QFN 制造商:Linear Technology 功能描述:BUCK, DUAL, CNTRL, 4.5-38V, 2MHZ, 38QFN 制造商:Linear Technology 功能描述:DP-SWREG/Controller, Dual, Fast, Accurate Step-Down Controller with Differential 制造商:Linear Technology 功能描述:DC-DC CONTROLLER, DUAL, BUCK, ADJ, QFN-38, Primary Input Voltage:38V, No. of Outputs:2, Output Current:25A, No. of Pins:38, Operating Temperature Min:-40C, Operating Temperature Max:125C, MSL:MSL 1 - Unlimited , RoHS Compliant: Yes |
| LTC3838IUHF-1#TRPBF | 制造商:Linear Technology 功能描述:IC REG CTRLR BUCK PWM CM 38QFN 制造商:Linear Technology 功能描述:DP-SWREG/Controller, Dual, Fast, Accurate Step-Down Controller with Differential 制造商:Linear Technology 功能描述:DC-DC CONTROLLER, DUAL, BUCK, ADJ, QFN-38, Primary Input Voltage:38V, No. of Outputs:2, Output Current:25A, No. of Pins:38, Operating Temperature Min:-40C, Operating Temperature Max:125C, MSL:MSL 1 - Unlimited , RoHS Compliant: Yes |
| LTC3838IUHF-2#PBF | 制造商:Linear Technology 功能描述:IC REG CTRLR BUCK PWM CM 38-QFN 制造商:Linear Technology 功能描述:BUCK DUAL CNTRL 4.5-38V 2MHZ 38QFN 制造商:Linear Technology 功能描述:DC-DC CONTROLLER BUCK 2MHZ QFN-38 制造商:Linear Technology 功能描述:BUCK, DUAL, CNTRL, 4.5-38V, 2MHZ, 38QFN 制造商:Linear Technology 功能描述:DP-SWREG/Controller, Dual, Fast, Accurate Step-Down Controller with Differential |
发布紧急采购，3分钟左右您将得到回复。