- 您現在的位置：買賣IC網 > PDF目錄30769 > LTC1871IMS-1 (LINEAR TECHNOLOGY CORP) SWITCHING CONTROLLER, 1000 kHz SWITCHING FREQ-MAX, PDSO10 PDF資料下載
參數資料
| 型號： | LTC1871IMS-1 |
| 廠商： | LINEAR TECHNOLOGY CORP |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | SWITCHING CONTROLLER, 1000 kHz SWITCHING FREQ-MAX, PDSO10 |
| 封裝： | PLASTIC, MSOP-10 |
| 文件頁數： | 7/36頁 |
| 文件大小： | 523K |
| 代理商： | LTC1871IMS-1 |
第1頁第2頁第3頁第4頁第5頁第6頁當前第7頁第8頁第9頁第10頁第11頁第12頁第13頁第14頁第15頁第16頁第17頁第18頁第19頁第20頁第21頁第22頁第23頁第24頁第25頁第26頁第27頁第28頁第29頁第30頁第31頁第32頁第33頁第34頁第35頁第36頁
LTC1871-1
15
18711fb
APPLICATIONS INFORMATION
DUTY CYCLE
0
MAXIMUM
CURRENT
SENSE
VOLTAGE
(mV)
100
150
0.8
18711 F10
50
0
0.2
0.4
0.5
1.0
200
Figure 10. Maximum SENSE Threshold Voltage vs Duty Cycle
from a lithium-ion battery or a 3.3V logic supply), then
sublogic-level threshold MOSFETs should be used.
Pay close attention to the BVDSS specications for the
MOSFETs relative to the maximum actual switch voltage in
the application. Many logic-level devices are limited to 30V
or less, and the switch node can ring during the turn-off of
the MOSFET due to layout parasitics. Check the switching
waveforms of the MOSFET directly across the drain and
source terminals using the actual PC board layout (not
just on a lab breadboard!) for excessive ringing.
During the switch on-time, the control circuit limits the
maximum voltage drop across the power MOSFET to about
150mV (at low duty cycle). The peak inductor current
is therefore limited to 150mV/RDS(ON). The relationship
between the maximum load current, duty cycle and the
RDS(ON) of the power MOSFET is:
RDS(ON) VSENSE(MAX)
1– DMAX
1
+
2
IO(MAX) T
The VSENSE(MAX) term is typically 150mV at low duty
cycle, and is reduced to about 100mV at a duty cycle of
92% due to slope compensation, as shown in Figure 10.
The ρT term accounts for the temperature coefcient of
the RDS(ON) of the MOSFET, which is typically 0.4%/°C.
Figure 11 illustrates the variation of normalized RDS(ON)
over temperature for a typical power MOSFET.
Another method of choosing which power MOSFET to
use is to check what the maximum output current is for a
given RDS(ON), since MOSFET on-resistances are available
in discrete values.
IO(MAX) = VSENSE(MAX)
1– DMAX
1
+
2
RDS(ON) T
It is worth noting that the 1 – DMAX relationship between
IO(MAX) and RDS(ON) can cause boost converters with a
wide input range to experience a dramatic range of maxi-
mum input and output current. This should be taken into
consideration in applications where it is important to limit
the maximum current drawn from the input supply.
Calculating Power MOSFET Switching and Conduction
Losses and Junction Temperatures
In order to calculate the junction temperature of the
power MOSFET, the power dissipated by the device must
be known. This power dissipation is a function of the
duty cycle, the load current and the junction temperature
itself (due to the positive temperature coefcient of its
RDS(ON)). As a result, some iterative calculation is normally
required to determine a reasonably accurate value. Since
the controller is using the MOSFET as both a switching
and a sensing element, care should be taken to ensure
that the converter is capable of delivering the required
load current over all operating conditions (line voltage
and temperature), and for the worst-case specications
JUNCTION TEMPERATURE (°C)
–50
ρ
TNORMALIZED
ON
RESISTANCE
1.0
1.5
150
18711 F11
0.5
0
50
100
2.0
Figure 11. Normalized RDS(ON) vs Temperature
相關PDF資料 |
PDF描述 |
|---|---|
| LTC1871EMS-1 | SWITCHING CONTROLLER, 1000 kHz SWITCHING FREQ-MAX, PDSO10 |
| LTC1871IMS-1#TR | SWITCHING CONTROLLER, 1000 kHz SWITCHING FREQ-MAX, PDSO10 |
| LTC1871EMS-1#TR | SWITCHING CONTROLLER, 1000 kHz SWITCHING FREQ-MAX, PDSO10 |
| LTC2908IDDB8-B1 | 6-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO8 |
| LTC2908CDDB8-B1#PBF | 6-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO8 |
相關代理商/技術參數 |
參數描述 |
|---|---|
| LTC1871IMS-1#PBF | 功能描述:IC REG CTRLR BST FLYBK CM 10MSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 標準包裝:2,500 系列:- PWM 型:電流模式 輸出數:1 頻率 - 最大:500kHz 占空比:96% 電源電壓:4 V ~ 36 V 降壓:無 升壓:是 回掃:無 反相:無 倍增器:無 除法器:無 Cuk:無 隔離:無 工作溫度:-40°C ~ 125°C 封裝/外殼:24-WQFN 裸露焊盤 包裝:帶卷 (TR) |
| LTC1871IMS-1#TRPBF | 功能描述:IC REG CTRLR BST FLYBK CM 10MSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 標準包裝:2,500 系列:- PWM 型:電流模式 輸出數:1 頻率 - 最大:500kHz 占空比:96% 電源電壓:4 V ~ 36 V 降壓:無 升壓:是 回掃:無 反相:無 倍增器:無 除法器:無 Cuk:無 隔離:無 工作溫度:-40°C ~ 125°C 封裝/外殼:24-WQFN 裸露焊盤 包裝:帶卷 (TR) |
| LTC1871IMS-7 | 制造商:Linear Technology 功能描述:DP-SWREG/Controller, No Rsense DC/DC Controller Boost, Flyback & SEPIC |
| LTC1871IMS-7#PBF | 功能描述:IC REG CTRLR BST FLYBK CM 10MSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 標準包裝:2,500 系列:- PWM 型:電流模式 輸出數:1 頻率 - 最大:500kHz 占空比:96% 電源電壓:4 V ~ 36 V 降壓:無 升壓:是 回掃:無 反相:無 倍增器:無 除法器:無 Cuk:無 隔離:無 工作溫度:-40°C ~ 125°C 封裝/外殼:24-WQFN 裸露焊盤 包裝:帶卷 (TR) |
| LTC1871IMS-7#TRPBF | 功能描述:IC REG CTRLR BST FLYBK CM 10MSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 標準包裝:2,500 系列:- PWM 型:電流模式 輸出數:1 頻率 - 最大:500kHz 占空比:96% 電源電壓:4 V ~ 36 V 降壓:無 升壓:是 回掃:無 反相:無 倍增器:無 除法器:無 Cuk:無 隔離:無 工作溫度:-40°C ~ 125°C 封裝/外殼:24-WQFN 裸露焊盤 包裝:帶卷 (TR) |
發(fā)布緊急采購，3分鐘左右您將得到回復。