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参数资料
| 型号： | LTC3873ITS8-5 |
| 厂商： | LINEAR TECHNOLOGY CORP |
| 元件分类： | 稳压器 |
| 英文描述： | SWITCHING CONTROLLER, PDSO8 |
| 封装： | 1 MM HEIGHT, PLASTIC, MO-193, TSOT-23, 8 PIN |
| 文件页数： | 15/16页 |
| 文件大小： | 170K |
| 代理商： | LTC3873ITS8-5 |
LTC3873-5
8
38735fb
OPERATION
VTURNON (nominally 4.1V) at least momentarily to enable
LTC3873-5 operation. The VCCvoltageisthenallowedtofall
to VTURNOFF (nominally 2.9V) before undervoltage lockout
disables the LTC3873-5. The RUN/SS pin can be driven
below VSHDN (nominally 0.7V) to force the LTC3873-5 into
shutdown. When the chip is off, the input supply current is
typically only 50μA. Keep in mind that VCC should exceed
the gate threshold voltage of the switching MOSFET for
safe operation.
Soft-Start
Leave the RUN/SS pin open to use the internal 3.3ms
soft-start. During the internal soft-start, a voltage ramp
limits the VITH. 3.3ms is required for ITH to ramp from
zero current level to full current level. The soft-start can
be lengthened by placing an external capacitor from the
RUN/SS pin to the GND. A 3μA current will charge the
capacitor, pulling the RUN/SS pin above the shutdown
threshold and a 15μA pull-up current will continue to ramp
RUN/SS to limit VITH during the start-up. When RUN/SS
is driven by an external logic, a minimum of 2.75V logic
is recommended to allow the maximum ITH range.
Light Load Operation
Under very light load current conditions, the ITH pin voltage
will be very close to 0.85V. As the load current decreases
further, an internal offset at the current comparator input
will assure that the current comparator remains tripped
(even at zero load current) and the regulator will start to
skip cycles in order to maintain regulation. This behavior
allows the regulator to maintain constant frequency down
to very light loads, resulting in low output ripple as well
as low audible noise and reduced RF interference while
providing high light load efciency.
Current Sense
During the switch on-time, the control circuit limits the
maximum voltage drop across the current sense com-
ponent to about 295mV, 110mV and 185mV at low duty
cycle with IPRG tied to VIN, GND or left oating respec-
tively. It is reduced with increasing duty cycle as shown
in Figure 4.
Figure 4. Maximum SENSE Threshold Voltage vs Duty Cycle
DUTY CYCLE (%)
1
0
MAXIMUM
CURRENT
SENSE
VOL
TAGE
(mV)
50
100
150
200
250
300
20
40
60
80
3873-5 F04
100
IPRG = HIGH
IPRG = FLOAT
IPRG = LOW
相关PDF资料 |
PDF描述 |
|---|---|
| LTC3873ETS8-5 | SWITCHING CONTROLLER, 240 kHz SWITCHING FREQ-MAX, PDSO8 |
| LTM-9134-2 | INFRARED, REMOTE CONTROL SUPPORT CIRCUIT, SMA3 |
| LTM-9134-3 | INFRARED, REMOTE CONTROL SUPPORT CIRCUIT, SMA3 |
| LTM-9134-4 | INFRARED, REMOTE CONTROL SUPPORT CIRCUIT, SMA3 |
| LTM-9134-5 | INFRARED, REMOTE CONTROL SUPPORT CIRCUIT, SMA3 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| LTC3873ITS8-5#PBF | 制造商:Linear Technology 功能描述:DP-SWREG/Isolated, Cut Tape No Rsense Constant Frequency Current Mode Boost/Flyb |
| LTC3873ITS8-5#TRMPBF | 功能描述:IC REG CTRLR BST FLYBK TSOT23-8 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) |
| LTC3873ITS8-5#TRPBF | 功能描述:IC REG CTRLR BST FLYBK TSOT23-8 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) |
| LTC3874EUFD#PBF | 制造商:Linear Technology 功能描述:IC REG CTRLR BUCK PWM CM 28QFN |
| LTC3874EUFD#TRPBF | 制造商:Linear Technology 功能描述:IC REG CTRLR BUCK PWM CM 28QFN |
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