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參數(shù)資料
| 型號： | LTC4257IS8-1 |
| 廠商： | LINEAR TECHNOLOGY CORP |
| 元件分類： | 電源管理 |
| 英文描述： | Power over Ethernet Interface Controller with Dual Current Limit |
| 中文描述： | 1-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO8 |
| 封裝： | 0.150 INCH, PLASTIC, SO-8 |
| 文件頁數(shù)： | 10/32頁 |
| 文件大?。?/td> | 1975K |
| 代理商： | LTC4257IS8-1 |
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LTC4267
10
4267f
specified to avoid corrupting the 25k
Ω
signature resistor
while also saving board space and cost. In addition, the in-
rush current limit requirement of the IEEE 802.3af standard
can cause large transient power dissipation in the PD. The
LTC4267 is designed to allow multiple turn-on sequences
without overheating the miniature 16-lead package. In the
event of excessive power cycling, the LTC4267 provides
thermal overload protection to keep the onboard power
MOSFET within its safe operating area.
OPERATION
The LTC4267 PD interface has several modes of opera-
tion depending on the applied input voltage as shown in
Figure 1 and summarized in Table 1. These modes satisfy
the requirements defined in the IEEE 802.3af specification.
The input voltage is applied to the V
PORTN
pin and must
be negative relative to the V
PORTP
pin. Voltages in the data
sheet for the PD interface portion of the LTC4267 are with
respect to V
PORTP
while the voltages for the switching
regulator are referenced to PGND. It is assumed that PGND
is tied to P
OUT
. Note the use of different ground symbols
throughout the data sheet.
Table 1. LTC4267 Operational Mode
as a Function of Input Voltage
INPUT VOLTAGE
(V
PORTN
with RESPECT to V
PORTP
) LTC4267 MODE OF OPERATION
0V to –1.4V
–1.5V to –10V
–11V to –12.4V
–12.5V to UVLO*
UVLO* to –57V
* V
PORTN
UVLO includes hysteresis.
Rising input threshold
–36.0V
Falling input threshold
–30.5V
Inactive
25k
Ω
Signature Resistor Detection
Classification Load Current Ramps up
from 0% to 100%
Classification Load Current Active
Power Applied to Switching Regulator
APPLICATIOU
W
U
U
Figure 1. Output Voltage,
P
W
R
G
D and PD
Current as a Function of Input Voltage
DETECTION V1
DETECTION V2
CLASSIFICATION
UVLO
TURN-ON
UVLO
OFF
POWER
BAD
UVLO
OFF
UVLO
ON
UVLO
TURN-OFF
τ
= R
LOAD
C1
PWRGD TRACKS
V
PORTN
–10
TIME
–20
–30
V
P
–40
–50
–10
TIME
–20
–30
P
O
–40
–50
–10
TIME
–20
–30
P
–40
–50
I
CLASS
P
I
LIM_LO
dV
dt
I
LIMIT
C1
=
POWER
BAD
POWER
GOOD
DETECTION I
1
CLASSIFICATION
I
CLASS
DETECTION I
2
LOAD, I
LOAD
(UP TO I
LIM_HI
)
CURRENT
LIMIT, I
LIM_LO
4267 F01
I
CLASS
DEPENDENT ON R
CLASS
SELECTION
I
LIM_LO
= 140mA (NOMINAL), I
LIM_HI
= 375mA (NOMINAL)
IN
LOAD
I
1
= V1 – 2 25k
I
2
= V2 – 2 25k
I
LOAD
= R
LIM_HI
)
V
PORTP
PSE
I
IN
LTC4267
R9
R
CLASS
V
OUT
C1
R
CLASS
PWRGD
P
OUT
PGND
V
PORTN
V
IN
TIME
VOLTAGES WITH RESPECT TO V
PORTP
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| LTC4257-1 | Power over Ethernet Interface Controller with Dual Current Limit |
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LTC4257IS8-1#PBF | 功能描述:IC CTRLR INTFACE PWR/ETHER 8SOIC RoHS:是 類別:集成電路 (IC) >> PMIC - 熱交換 系列:- 標(biāo)準(zhǔn)包裝:50 系列:- 類型:熱交換控制器 應(yīng)用:-48V 遠程電力系統(tǒng)，AdvancedTCA ? 系統(tǒng)，高可用性 內(nèi)部開關(guān):無 電流限制:可調(diào) 電源電壓:11.5 V ~ 14.5 V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:10-TFSOP，10-MSOP（0.118"，3.00mm 寬） 供應(yīng)商設(shè)備封裝:10-MSOP 包裝:管件 |
| LTC4257IS8-1#TR | 功能描述:IC CONTROLLER POE INTERFAC 8SOIC RoHS:否 類別:集成電路 (IC) >> PMIC - 熱交換 系列:- 標(biāo)準(zhǔn)包裝:50 系列:- 類型:熱交換控制器 應(yīng)用:-48V 遠程電力系統(tǒng)，AdvancedTCA ? 系統(tǒng)，高可用性 內(nèi)部開關(guān):無 電流限制:可調(diào) 電源電壓:11.5 V ~ 14.5 V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:10-TFSOP，10-MSOP（0.118"，3.00mm 寬） 供應(yīng)商設(shè)備封裝:10-MSOP 包裝:管件 |
| LTC4257IS8-1#TRPBF | 功能描述:IC CTRLR INTFACE PWR/ETHER 8SOIC RoHS:是 類別:集成電路 (IC) >> PMIC - 熱交換 系列:- 標(biāo)準(zhǔn)包裝:50 系列:- 類型:熱交換控制器 應(yīng)用:-48V 遠程電力系統(tǒng)，AdvancedTCA ? 系統(tǒng)，高可用性 內(nèi)部開關(guān):無 電流限制:可調(diào) 電源電壓:11.5 V ~ 14.5 V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:10-TFSOP，10-MSOP（0.118"，3.00mm 寬） 供應(yīng)商設(shè)備封裝:10-MSOP 包裝:管件 |
| LTC4258 | 制造商:LINER 制造商全稱:Linear Technology 功能描述:Quad IEEE 802.3at Power over Ethernet Controller |
| LTC4258_09 | 制造商:LINER 制造商全稱:Linear Technology 功能描述:Quad IEEE 802.3af Power over Ethernet Controller with Integrated Detection |
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