- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄69008 > LTC4269IDKD-2 (LINEAR TECHNOLOGY CORP) SWITCHING CONTROLLER, 560 kHz SWITCHING FREQ-MAX, PDSO32 PDF資料下載
參數(shù)資料
| 型號(hào)： | LTC4269IDKD-2 |
| 廠商： | LINEAR TECHNOLOGY CORP |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | SWITCHING CONTROLLER, 560 kHz SWITCHING FREQ-MAX, PDSO32 |
| 封裝： | 7 X 4 MM, PLASTIC, M0-229, DFN-32 |
| 文件頁數(shù)： | 11/34頁 |
| 文件大小： | 383K |
| 代理商： | LTC4269IDKD-2 |
第1頁第2頁第3頁第4頁第5頁第6頁第7頁第8頁第9頁第10頁當(dāng)前第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
LTC4269-2
42692fb
Asilicondiodebridgecanconsumeover4%oftheavailable
powerinsomePDapplications.UsingSchottkydiodescan
help reduce the power loss with a lower forward voltage.
A Schottky bridge may not be suitable for some high
temperature PD applications. The leakage current has
a temperature and voltage dependency that can reduce
the perceived signature resistance. In addition, the IEEE
802.3af/atspecificationmandatestheleakageback-feeding
throughtheunusedbridgecannotgeneratemorethan2.8V
across a 100k resistor when a PD is powered with 57V.
Sharing Input Diode Bridges
At higher temperatures, a PD design may be forced to
consider larger bridges in a bigger package because the
maximum operating current for the input diode bridge is
drastically derated. The larger package may not be accept-
able in some space-limited environments.
One solution to consider is to reconnect the diode bridges
so that only one of the four diodes conducts current in
each package. This configuration extends the maximum
operating current while maintaining a smaller package
profile. Figure 7 shows how the reconnect the two diode
bridges.Consultthediodebridgevendorsforthede-rating
curve when only one of four diodes is in operation.
Input Capacitor
The IEEE 802.3af/at standard includes an impedance
requirement in order to implement the AC disconnect
function. A 0.1F capacitor (C14 in Figure 7) is used to
meet this AC impedance requirement. Place this capacitor
as close to the LTC4269-2 as possible.
Transient Voltage Suppressor
The LTC4269-2 specifies an absolute maximum voltage of
100V and is designed to tolerate brief overvoltage events.
However, the pins that interface to the outside world can
routinely see excessive peak voltages. To protect the
LTC4269-2, install a transient voltage suppressor (D3)
betweentheinputdiodebridgeandtheLTC4269-2asclose
to the LTC4269-2 as possible as shown in Figure 7.
Classification Resistor (RCLASS)
The RCLASS resistor sets the classification load current,
corresponding to the PD power classification. Select the
value of RCLASS from Table 2 and connect the resistor
between the RCLASSandVPORTNpinsasshowninFigure 4,
or float the RCLASS pin if the classification load current is
not required. The resistor tolerance must be 1% or better
to avoid degrading the overall accuracy of the classifica-
tion circuit.
Load Capacitor
The IEEE 802.3af/at specification requires that the PD
maintains a minimum load capacitance of 5F and does
not specify a maximum load capacitor. However, if the
load capacitor is too large, there may be a problem with
inadvertent power shutdown by the PSE.
This occurs when the PSE voltage drops quickly. The input
diode bridge reverses bias, and the PD load momentarily
powers off the load capacitor. If the PD does not draw
power within the PSE’s 300ms disconnection delay, the
PSE may remove power from the PD. Thus, it is necessary
to evaluate the load current and capacitance to ensure that
an inadvertent shutdown cannot occur.
The load capacitor can store significant energy when fully
charged.ThePDdesignmustensurethatthisenergyisnot
inadvertently dissipated in the LTC4269-2. For example,
if the VPORTP pin shorts to VPORTN while the capacitor
is charged, current will flow through the parasitic body
diode of the internal MOSFET and may cause permanent
damage to the LTC4269-2.
T2P Interface
When a 2-event classification sequence successfully
completes, the LTC4269-2 recognizes this sequence,
and provides an indicator bit, declaring the presence of
a Type 2 PSE. The open-drain output provides the option
to use this signal to communicate to the LTC4269-2 load,
or to leave the pin unconnected.
Figure 8 shows two interface options using the T2P
pin and the opto-isolator. The T2P pin is active low and
connects to an optoisolater to communicate across the
applicaTions inForMaTion
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| LTC4269CDKD-2 | SWITCHING CONTROLLER, 560 kHz SWITCHING FREQ-MAX, PDSO32 |
| LTC4269IDKD-2#TR | SWITCHING CONTROLLER, 560 kHz SWITCHING FREQ-MAX, PDSO32 |
| LTC4412IS6#TR | 1-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO6 |
| LTC4412IS6#TRM | 1-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO6 |
| LTC4558EUD#TR | 1-CHANNEL POWER SUPPLY SUPPORT CKT, PQCC20 |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LTC4269IDKD-2#PBF | 功能描述:IC PD/SYNC FORWARD CTRLR 32-DFN RoHS:是 類別:集成電路 (IC) >> PMIC - 熱交換 系列:- 產(chǎn)品培訓(xùn)模塊:Obsolescence Mitigation Program 標(biāo)準(zhǔn)包裝:100 系列:- 類型:熱插拔開關(guān) 應(yīng)用:通用 內(nèi)部開關(guān):是 電流限制:可調(diào) 電源電壓:9 V ~ 13.2 V 工作溫度:-40°C ~ 150°C 安裝類型:表面貼裝 封裝/外殼:10-WFDFN 裸露焊盤 供應(yīng)商設(shè)備封裝:10-TDFN-EP（3x3） 包裝:管件 |
| LTC4269IDKD-2#TRPBF | 功能描述:IC PD/SYNC FORWARD CTRLR 32-DFN RoHS:是 類別:集成電路 (IC) >> PMIC - 熱交換 系列:- 產(chǎn)品培訓(xùn)模塊:Obsolescence Mitigation Program 標(biāo)準(zhǔn)包裝:100 系列:- 類型:熱插拔開關(guān) 應(yīng)用:通用 內(nèi)部開關(guān):是 電流限制:可調(diào) 電源電壓:9 V ~ 13.2 V 工作溫度:-40°C ~ 150°C 安裝類型:表面貼裝 封裝/外殼:10-WFDFN 裸露焊盤 供應(yīng)商設(shè)備封裝:10-TDFN-EP（3x3） 包裝:管件 |
| LTC4269IDKD-2-PBF | 制造商:LINER 制造商全稱:Linear Technology 功能描述:IEEE 802.3at High Power PD and Synchronous Forward Controller with AUX Support |
| LTC4269IDKD-2-TR | 制造商:LINER 制造商全稱:Linear Technology 功能描述:IEEE 802.3at High Power PD and Synchronous Forward Controller with AUX Support |
| LTC4269IDKD-2-TRPBF | 制造商:LINER 制造商全稱:Linear Technology 功能描述:IEEE 802.3at High Power PD and Synchronous Forward Controller with AUX Support |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。