參數(shù)資料
型號(hào): LTC4259A
廠商: Linear Technology Corporation
英文描述: Quad IEEE 802.3af Power over Ethernet Controller with AC Disconnect
中文描述: 四IEEE 802.3af標(biāo)準(zhǔn)與AC電源斷開(kāi)以太網(wǎng)控制器
文件頁(yè)數(shù): 30/32頁(yè)
文件大?。?/td> 326K
代理商: LTC4259A
LTC4259A
30
4259Af
APPLICATIOU
W
U
U
if a PSE powers a PD it must be able to provide the
maximum power level requested by the PD based on the
PD’s classification. The specification does allow a PSE to
choose not to power a port because the PD requires more
power than the PSE has left to deliver. If a PSE is built with
a V
EE
supply capable of less than 15.4W (number of
PSE’s Ethernet ports), it must implement a power alloca-
tion algorithm that prevents ports from being powered
when there is insufficient power. Because the specifica-
tion also requires the PSE to supply 400mA at up to a 5%
duty cycle, the V
EE
supply capability should be at least a
few percent more than the maximum total power the PSE
will supply to PDs. Finally, the LTC4259As draw current
from V
EE
. If the V
DD
supply is generated from V
EE
, that
power divided by the switcher efficiency must also be
added to the V
EE
supply’s capability.
OSCIN Input
AC disconnect also relies on an oscillating signal applied
to the OSCIN pin. Requirements for this signal are pro-
vided in the OSCIN Input and Oscillator Requirements
section. Out-of-band noise on the OSCIN pin will disrupt
the LTC4259A’s ability to sense the absence of a PD. Any
noise present at the OSCIN pin is amplified by the LTC4259A
and driven out of the DETECT pins (of powered ports with
AC disconnect enabled). Due to the amount of capacitance
connected to the DETECT pins, driving this noise can
easily require more than I
ACDMIN
, tripping the DETECT pin
current sense and keeping the port powered. During
circuit board layout, keep wiring from the oscillator to the
OSCIN pin away from noise sources like digital clock and
data lines. A single-stage RC lowpass filter (shown in
Figure 20) will attenuate out-of-band noise.
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相關(guān)代理商/技術(shù)參數(shù)
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LTC4259A-1 制造商:LINER 制造商全稱:Linear Technology 功能描述:Synchronous No-Opto Flyback Controller
LTC4259ACGW 功能描述:IC CTRLR POE QUAD AC DISC 36SSOP RoHS:否 類別:集成電路 (IC) >> 接口 - 控制器 系列:- 標(biāo)準(zhǔn)包裝:2,450 系列:- 控制器類型:SPI 總線至 I²C 總線橋接 接口:I²C,串行,SPI 電源電壓:2.4 V ~ 3.6 V 電流 - 電源:11mA 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:24-VFQFN 裸露焊盤(pán) 供應(yīng)商設(shè)備封裝:24-HVQFN(4x4) 包裝:托盤(pán) 配用:568-3511-ND - DEMO BOARD SPI TO I2C 其它名稱:935286452157SC18IS600IBSSC18IS600IBS-ND
LTC4259ACGW#PBF 功能描述:IC CTRLR POE QUAD AC DISC 36SSOP RoHS:是 類別:集成電路 (IC) >> 接口 - 控制器 系列:- 標(biāo)準(zhǔn)包裝:2,450 系列:- 控制器類型:SPI 總線至 I²C 總線橋接 接口:I²C,串行,SPI 電源電壓:2.4 V ~ 3.6 V 電流 - 電源:11mA 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:24-VFQFN 裸露焊盤(pán) 供應(yīng)商設(shè)備封裝:24-HVQFN(4x4) 包裝:托盤(pán) 配用:568-3511-ND - DEMO BOARD SPI TO I2C 其它名稱:935286452157SC18IS600IBSSC18IS600IBS-ND
LTC4259ACGW#TR 功能描述:IC CTRLR POE QUAD AC DISC 36SSOP RoHS:否 類別:集成電路 (IC) >> 接口 - 控制器 系列:- 標(biāo)準(zhǔn)包裝:2,450 系列:- 控制器類型:SPI 總線至 I²C 總線橋接 接口:I²C,串行,SPI 電源電壓:2.4 V ~ 3.6 V 電流 - 電源:11mA 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:24-VFQFN 裸露焊盤(pán) 供應(yīng)商設(shè)備封裝:24-HVQFN(4x4) 包裝:托盤(pán) 配用:568-3511-ND - DEMO BOARD SPI TO I2C 其它名稱:935286452157SC18IS600IBSSC18IS600IBS-ND
LTC4259ACGW#TRPBF 功能描述:IC CTRLR POE QUAD AC DISC 36SSOP RoHS:是 類別:集成電路 (IC) >> 接口 - 控制器 系列:- 標(biāo)準(zhǔn)包裝:2,450 系列:- 控制器類型:SPI 總線至 I²C 總線橋接 接口:I²C,串行,SPI 電源電壓:2.4 V ~ 3.6 V 電流 - 電源:11mA 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:24-VFQFN 裸露焊盤(pán) 供應(yīng)商設(shè)備封裝:24-HVQFN(4x4) 包裝:托盤(pán) 配用:568-3511-ND - DEMO BOARD SPI TO I2C 其它名稱:935286452157SC18IS600IBSSC18IS600IBS-ND