飞思卡尔以太网供电器件满足您的供电需求- 飞思卡尔厂商_在线座谈

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主题：飞思卡尔以太网供电器件满足您的供电需求
在线问答：
[主持人：ChinaECNet]	各位听众（网友），上午好！欢迎参加中电网在线座谈。今天，我们有幸邀请到Freescale公司的专家就“飞思卡尔以太网供电器件满足您的供电需求”举行在线座谈。在座谈中，您可就您关心的问题与Freescale公司的专家在线进行直接、实时的对话交流。中电网衷心希望通过大家的共同努力，不仅能够增进各位听众（网友）对“飞思卡尔以太网供电器件满足您的供电需求”的了解和掌握，而且能够为大家事业的发展带来裨益。	[2006-11-9 9:54:57]
[问：yuanli25]	DC/DC的输出电压如何调节？通过改变开关频率吗？调节是否方便？
[答：飞思卡尔]	要调整 DC-DC 的输出电压您可以调整 feedback potential divier 的比例，至于是否方便这很难说要看您的 DC-DC design.	[2006-11-9 10:38:29]
[问：yuanli25]	DC/DC 输出可调范围为多少？
[答：飞思卡尔]	DC/DC 的输出范围没有规定要视付您的设计。	[2006-11-9 10:45:03]
[问：dreamtofling]	Demo 板的供应以及技术支持情况如何？
[答：飞思卡尔]	Our products and boards are readily available. Pls approach our Freescale sales office or support group in your region.	[2006-11-9 10:45:51]
[主持人：ChinaECNet]	我们已经进入问答阶段如果听众想重温演讲或内容可以点击下面“回顾演示”重看演讲。	[2006-11-9 10:46:08]
[问：yuanli25]	End-Point POE 是否只支持数据线上供电？
[答：飞思卡尔]	End－point poe 支持数据线队供电，也支持空余线队供电。但是目前 Endpoint 方式采用数据线队供电。在 midspan 方式中，必须使用空余线对。	[2006-11-9 10:46:14]
[主持人：ChinaECNet]	在此回答问题的专家是Freescale公司的：Harriet Mak、Norman Chan、Robin Ma、Mars Leung、WS Wong、Romeo Phone、Eric Wu和Caroline。	[2006-11-9 10:46:38]
[问：snowshadow]	飞思卡尔的 PD 器件能提供的端口数最高能达到多少?
[答：飞思卡尔]	MC34670 supports only one PD device.	[2006-11-9 10:47:15]
[问：vviva]	飞思卡尔在 POE 方面与 Powerdsine，LT，等厂商相比有哪些优势和劣势？我希望听到一个客观公正的评价，谢谢！
[答：飞思卡尔]	You need to distinguished from PSE and PD. Our part is the PD, client end. Apart from Freescale being very competitive on price (depending on qty), our device can yield a very efficient design in terms of power conversion efficiency. We are able to achieve close to 88% or better. Also our MC34670 has very useful features like Leading Edge Blanking and Adjustable Oscillator.	[2006-11-9 10:47:44]
[问：wliush]	MCZ34670 都有哪些封装形式?
[答：飞思卡尔]	MCZ34670 采用 SOIC 20 引脚的封装形式，具体尺寸请参考数据手册。	[2006-11-9 10:49:24]
[问：chpeng81]	MCZ34670 和其他厂家的 PoE 产品如 SI3400, Isl6844 相比有什么特点和优势吗？
[答：飞思卡尔]	Apart from Freescale MCZ34670 being very competitive in price (depending on quantity), our device can yield a very efficient design in terms of power conversion efficiency. We are able to achieve close to 88% or better. Also our MC34670 has very useful features like Leading Edge Blanking and Adjustable Oscillator.	[2006-11-9 10:51:07]
[问：lijin_as]	MCZ34670 评估板有些什么功能? 价格如何?
[答：飞思卡尔]	评估板 KIT34670EVB。可以验证 MCZ34670 的主要特性。它提供符合 IEEE802.3af 规范的受电设备 PD 接口；5V 隔离电压输出；可调节浪涌电流；欠压监控调节；可配置设备类型为 0 到 4 类设备等。关于价格，请和我们销售代表和我们的代理商联系。联系方式在我们的中文网页上。 http://www.freescale.com.cn/others/wheretobuy/index.asp	[2006-11-9 10:53:16]
[问：telsun]	MCZ34670 是供电芯片, 那么, 设备受电由专门的电路要求吗? 即由专门的芯片吗?
[答：飞思卡尔]	MCZ34670 is POE powered device, that is to say MCZ34670 will get power from PSE equipment by Ethernet cable.	[2006-11-9 10:54:18]
[问：dreamtofling]	MCZ34670 有 5v 系列的芯片吗，再有封装有几种?
[答：飞思卡尔]	MCZ34670 是用支援 IEEE802.3af (是 48V input) 所以沒有 5V, 目前封裝只有一種。如果您所说的是输出电压的话那 MCZ34670 是没有限制输出电压的。	[2006-11-9 10:55:28]
[问：huangz]	MCZ34670 有没有瞬态过电压保护？如果没有, 如何考虑在 PD 端加上瞬态过电压保护功能？
[答：飞思卡尔]	MCZ34670 有瞬态过压保护功能，当输入电压高于 65V 左右时，过压保护功能会起作用。另外需要外加 TVS 作保护。	[2006-11-9 10:55:52]
[问：carlye]	MCZ34670 有那些功能? 是否具有 ESD 保护功能?
[答：飞思卡尔]	本次座谈的主要目的是向各位介绍 MCZ34670 的功能和使用。它具有 ESD 保护功能，＋/-2000V （Human Body model）。+/-200V (Machine Model)	[2006-11-9 10:56:43]
[问：yuanli25]	MCZ34670 中 DC/DC 的输出为可调吗？
[答：飞思卡尔]	因为 MCZ34670 是一个 DC-DC 控制器所以 DC-DC 的输出电压可以透过调整外部器件调整。	[2006-11-9 11:00:38]
[问：carlye]	PD 的分类是依据什么进行? 是电压还是电流还是别的什么?
[答：飞思卡尔]	The PD classification allows the PSE to identify four different (power) classes depending on the required power that the PD will draw during normal operation. During classification probing by the PSE, the PD applies the appropriate load current onto the line. The PSE measures the load current and can determine the classification.	[2006-11-9 11:01:12]
[主持人：ChinaECNet]	各位观众，现在用户提问很踊跃，专家正在逐一回答。请耐心等待您问题的答案，同一问题请不要多次提交。	[2006-11-9 11:01:44]
[问：Yichengjameslu]	POE 采用直流供电, 在直流电源注入不支持 PoE 的设备时是不是会发生不安全问题?
[答：飞思卡尔]	No, it should be safe to plug in non-compliant PoE PD because in the IEEE802.3af standard there is a Signature resistor detection feature, during signature detection phase the Power Sourcing Equipment (PSE) applies a voltage in the range 2.7 V - 10.1 V on the PI connector and looks for the 25 k? signature resistor. If 25k? signature resistor is not presented (case for non-compliant PoE PD), PSE will terminate the power supply to the PD.	[2006-11-9 11:02:32]
[问：zluyao]	POE 的供电距离有没有限制? 是多少？它和那些因素有关?
[答：飞思卡尔]	PoE 供电距离是 100m, 这和电缆的 quality 有关，但是按规定用 CAT5, CAT5-E, CAT6 就应该没有问题。	[2006-11-9 11:03:16]
[问：cai517]	POE 的最大供电功率 15W 是对全体 PD 还是单个 PD 而言?
[答：飞思卡尔]	是针对一个 PD 受电设备的。我们介绍了 MCZ34670 可以设置 Rclass 分类电阻，以便让 PSE 端对之进行分类识别。	[2006-11-9 11:04:12]
[问：chpeng81]	POE 对短路或过载保护的能力如何? 响应时间有多快?
[答：飞思卡尔]	There is in-rush current limit, over current and over-voltage protection function in MC34670. The response time will be much under 1ms.	[2006-11-9 11:04:23]
[问：jenired]	POE 供电的通路是否有限? 如果采用这种网络功率截取方法的设备过多，能否对网络的稳定运行构成威胁？
[答：飞思卡尔]	POE only provides 350mA/15W max power to a network equipment. The PSE will limit connected PD devices to meet the POE spec. So it will not be influenced to network stability.	[2006-11-9 11:07:08]
[问：paoapp]	POE 是否也需要加 ESD 保护?
[答：飞思卡尔]	根据您产品使用环境要求，我们的 MCZ34670 提供＋/-2000VESD 保护功能。	[2006-11-9 11:07:51]
[问：lijin_as]	POE 中使用直流供电, 为什么还需要桥式整流器? 它起什么样作用?
[答：飞思卡尔]	请您观看我们本次座谈的材料，其中我们讨论了全桥整流器的作用。	[2006-11-9 11:09:17]
[问：snowshadow]	PSE 能否对受电设备有软起动功能以减小浪涌电流?
[答：飞思卡尔]	飞思卡尔的 MCZ34670 是提供多种智能方式的 PD 芯片，MCZ34670 可以通过调节外部电阻值来设置浪涌电流的门限值。当设置为较小值时，受电设备就可以对 PSE 端索取较小少的电流。以减少浪涌。并且 MCZ34670 芯片又提供软起动功能。	[2006-11-9 11:09:46]
[问：wjarjar]	RJ-45 中信号传输对 POE 的影响有多大? 所引起的噪音能占多大的比例? 如何进行避免?
[答：飞思卡尔]	RJ45 信号线上的信号对 POE 供电的影响不大，因为电源可在空余线对上传输，当电源在数据线上传输时数据的电压会通过 PD 稳压电路把数据电压波过滤。	[2006-11-9 11:09:49]
[问：yjiangty]	Why 48v not 24v DC?
[答：飞思卡尔]	34670 fully supports the IEEE802.3af standard. 48V is in the range of that standard.	[2006-11-9 11:09:54]
[问：wliush]	从开始对 PD 进行检测到 48V 正常供电, 这个过程有多长时间?
[答：飞思卡尔]	The maximum detection time is 500ms, the maximum power turn on time is 400ms. Therefore it can take up to 900ms from the moment PD start to get into detection phase till 48V is applied	[2006-11-9 11:09:58]
[问：yuanli25]	大家都知道 DC 的掉电检测在低功耗的应用是可能会误判断为设备移除，请问贵公司是怎样解决这个问题的？
[答：飞思卡尔]	PSE will issue a signature detection voltage to detect PD device existed or not, so there will always be minimal current drawn. So there is no problem for the function. The signature detection is defined in the POE spec, IEEE 802.3af.	[2006-11-9 11:10:54]
[问：cai517]	当供电距离较远时，需要加入中继器。那中继器也是PoE吗？应该不是吧。
[答：飞思卡尔]	This would depends if the repeater has PSE inserted. Normally, if it is not specified then it is not. PoE is a capability added, not the repeater itself.	[2006-11-9 11:13:52]
[问：MB45]	电流是多少？供电距离最大是多少？对网线有何要求？
[答：飞思卡尔]	您的问题不太清楚一般来说 IEEE802.3af 规定 PD 功率在 13 瓦以下供电距离是 100m 按规定 cable 用 CAT5, CAT5-E, CAT6 就可以。	[2006-11-9 11:14:10]
[问：jhonsun12]	对 PSE 电源有特殊要求吗? 使用普通的 48V 电源是否可以给 PD 供电?
[答：飞思卡尔]	You would be able to do this providing that the inrush current, OVLO, over voltage are not violated with the settings and the device limits as transients and surges could be very high. However, we do not recommend doing this as this would not comply to the PoE IEEE 802.3af standard, and this standard mandates cable requirements and safety issues. So it is recommended that you use the PD with a PSE.	[2006-11-9 11:14:35]
[问：zoo]	隔离变压器的设计有什么要求？有参考资料吗？
[答：飞思卡尔]	您是指那个变压器？如果是 LAN side 请按 IEEE802.3。如果是 DC-DC 方面就跟你 DC-DC 有关。	[2006-11-9 11:16:50]
[问：yuanli25]	功率分级是怎样分级的？请问 PD 是否要加一个分级电阻？
[答：飞思卡尔]	There are 4 levels for PD classification, 0 for 0.44-12.95W(, 1 for 0.44 to 3.84W, 2 for 3.84 to 6.49W, 3 for 6.49 to 12.95W. The classification resistors is 4.42Kohm(0), 475ohms(1), 261ohms(2) and 169ohms(3). You could see the details in MC34670 datasheet.	[2006-11-9 11:19:17]
[问：yuanli25]	既然 MCZ34670 兼容非标准设备，那非标准的供电设备输出电压是否有要求?
[答：飞思卡尔]	PD input voltage is limited from 37 to 57V.	[2006-11-9 11:20:28]
[问：siufean]	加上偏置磁圈之后可以使效率提高到 80+，这个偏置磁圈是什么？
[答：飞思卡尔]	In cases where the external MOSFET gate drive pulls more than 5.0 mA, an auxiliary winding is needed to reduce the power dissipation in the internal high voltage LDO. The internal high voltage regulator of the 34670 regulates from the input voltage across VPWR and VIN down to the VDD voltage. During start-up the high voltage regulator provides the necessary voltage for the internal gate driver to commence switching. If the external MOSFET gate drive pulls less than 3.0 mA under all circumstances, an auxiliary transformer winding that usually provides the bias voltage for the chip and the gate driver is not required. The aux winding has an higher output voltage than the LDO and delivers all the current to drive the gate.	[2006-11-9 11:21:51]
[问：yuanli25]	兼容非标准供电是否指非标准的 48V 供电设备？
[答：飞思卡尔]	能兼容以前非标准的 48V 供电设备的。	[2006-11-9 11:21:58]
[问：telsun]	每一片芯片, 只能实现向一条网线供电吗?
[答：飞思卡尔]	我对您的问题的理解是 MCZ34670 只能向一个 PD 设备提供电源。是的，MCZ34670 是向 PD 受电设备提供电源并且符合 IEEE802.3af 规范的要求。	[2006-11-9 11:22:15]
[问：hunklee]	目前国际上有没有超过 350mA 的 POE 的供电标准，如 500mA 或 1A？
[答：飞思卡尔]	At this moment the answer is no based on the current IEEE802.3af specification. However, the upcoming new IEEE802.3at standard is expected to supply 30W power which in turn should be able to support higher current.	[2006-11-9 11:23:12]
[问：jenired]	目前来说, 以太网供电 (POE) 所存在的主要问题是什么? 有什么解决方案?
[答：飞思卡尔]	您的问题范围指向不明确。如果从市场发展的角度讲，它是比较新的技术，需要大家的接受和认同。成本，方便性，实用性等等。从技术角度讲，PSE 端的设计相对 PD 端较复杂，但是使用中跨方式可以分担其的负荷。POE 设计的灵活性可以提供不同的手段达到目的。	[2006-11-9 11:25:18]
[问：wjarjar]	能否详细介绍如何对 PD 进行检测? 包括那些内容?
[答：飞思卡尔]	首先，PSE 向 PD 发送 2-10v 的检测电压，用来检测 PD 端的特征电阻是否是标准规定的 25Kohm。如果检测到是符合标准的 PD 设备后，PSE 会加大功率，发送 15-20V 的检测电压，以便对 PD 设备的功率进行分类。本次座谈中向大家介绍了对 PD 检测的方式，请您观看我们的座谈材料。或查看我们产品的数据手册。	[2006-11-9 11:26:00]
[问：ccb21cn]	你好，802.3af 与普通的以太网一样吗？如果能用到普通的以太网上，能提供多大的功率或电流输出，谢谢！
[答：飞思卡尔]	802.3af is standard that build on 普通的以太网. The objective is to make 普通的以太网 provide dc supply function.	[2006-11-9 11:26:10]
[问：bigsleeper]	请问, 与别的 POE 方案相比, MCZ34670 的最大的优势是什么?
[答：飞思卡尔]	Apart from our MCZ34670 being very competitive on price (depending on qty), our device can yield a very efficient design in terms of power conversion efficiency. We are able to achieve close to 88% or better.Also our MCZ34670 has very useful features like Leading Edge Blanking and Adjustable Oscillator.	[2006-11-9 11:26:27]
[问：zluyao]	请问 MCZ34670 有没有热保护和热插拔功能?
[答：飞思卡尔]	MCZ34670 是有热保护和热插拔功能的。	[2006-11-9 11:27:57]
[问：yuanli25]	请问 MCZ34670 支持哪一种掉电检测方式？是直流掉电检测还是交流掉电检测，或者是两者都支持？
[答：飞思卡尔]	You can utilize the under voltage lock out on MCZ34670 to do this	[2006-11-9 11:28:08]
[问：忘情水663563958256-2003]	请问多少钱?
[答：飞思卡尔]	We offer very competitive pricing for sizeable volumes. Please approach Freescale sales representative in your region.	[2006-11-9 11:28:36]
[问：winday]	请问该器件是否能采用非隔离输出？以减低成本。
[答：飞思卡尔]	是可以的。	[2006-11-9 11:29:02]
[问：paoapp]	请问供货周期多长？飞思卡尔是否提供相应的交换机方案？
[答：飞思卡尔]	If the switch scheme is relating PoE operation, we do not, else you need to approach our networking product sales group within your region. For leadtime, it depends on your volumn, please approach our sales representative in your region.	[2006-11-9 11:30:20]
[问：yuanli25]	请问飞思卡尔有 PSE 的集成解决方案吗？
[答：飞思卡尔]	For PSE, currently we do not for our general product offering.	[2006-11-9 11:30:28]
[问：yukai]	请问网络变压器应该如何选择？谢谢！
[答：飞思卡尔]	Base on the IEEE 802.3af specification requirement to choose the isolation transformer.	[2006-11-9 11:30:34]
[问：yuanli25]	请问我们是不是可以这样简单的理解，MCZ34670 是支持标准的 PD 再加入了一个 DC/DC？
[答：飞思卡尔]	简单地說是可以这样理解。	[2006-11-9 11:31:19]
[问：yuanli25]	请问用 MCZ34670 开发一个输出 5V 的 PD 估计需要多少成本？器件占用面积大约为多少？这个在实际应用时比较重要。
[答：飞思卡尔]	我们提供了一个评估板套件，还有 MCZ34670 数据手册中给出了应用连接图。您可以参考这些来估算成本。关于器件的尺寸，也在数据手册中列出了。关于产品的价格，请和我们的销售和代理商联系。	[2006-11-9 11:32:53]
[问：lijin_as]	軟體的開發環境為何? 是否有提供簡易發展版做測試?
[答：飞思卡尔]	For our PD device, no programming is needed. The settings are accomplished by resistor settings. But for the PSE, this would depend on which devices you are using.	[2006-11-9 11:33:04]
[问：zbq0204]	什么是以太网在线供电 (PoE)? 对用户来说，哪种方式最合适呢？它适合什么环境？
[答：飞思卡尔]	PoE 是一種電源管理技術，可作為設備端直接嵌入交換機中，或是獨立的中繼集線器。IEEE 於 2003 年中正式核准了 802.3af 標準，802.3af 標準規定路由器、交換機與集線器，經由乙太網路電纜逕向 VOIP、WLAN AP（Access Point）等供電方式。	[2006-11-9 11:33:05]
[问：helen_hui_liu]	实现 802.3af 标准的 POE, 是否意味要更换新的交换机?
[答：飞思卡尔]	有兩種選擇 a. 可以不必換現有的交換機只需加裝一台Power injection將訊號與電源一起注入網路傳輸線 b. 換一台有POE功能的交換機	[2006-11-9 11:33:30]
[问：paoapp]	使用 MCZ34670 设计，产品的总的额外成本大约多少？
[答：飞思卡尔]	This would depends on the topology (isolated/non isolated/flyback/forward) of your DC-Dc needs, transformer costs etc. But for our device, it would be marginal cost to your BOM. Pls approach Freescale sales office or support group in your region for pricing.	[2006-11-9 11:34:22]
[问：zhangwq]	使用 POE 后，隔离变压器要调整吗?
[答：飞思卡尔]	是的。请看我们的应用笔记 AN3279，它详细的介绍了变压器部分的使用。 No modification to the isolation transformer is needed if power is supplied by spare pair. If power is supplied by data pair then you need an isolation transformer capable of allowing the DC to pass through	[2006-11-9 11:35:30]
[问：lytxxm]	我的设备网速要求不高，所以网线长度大于 100m 也没有问题，所以我更关心这个芯片可以正常供电的最大长度，要大于100m的极限值。
[答：飞思卡尔]	MCZ34670 的欠压锁闭（UVLO）功能要求您输入电压不小于 34V。所以只要保证供电电压稳定，可以适当的增加传输距离。	[2006-11-9 11:36:42]
[问：lxlcqcs]	我是个入门者, 请问 PD 和 PSE 通过 RJ-45 传输的 TX 发送和接收 RX 信息是个什么样的信号? 发送和接收是否需要同步? 它对变压器有什么特别的要求?
[答：飞思卡尔]	It is Ethernet protocol signal. It is not necessary for synchronization. No need to modify transformer circuits for POE application.	[2006-11-9 11:38:05]
[问：yuanli25]	我一直在从事这方面的设计，建议是不是能把整流桥集成到 PD 中，这样即能达到极性保护的作用也可以缩小布板面积?
[答：飞思卡尔]	We have road maps for these devices and features. Your suggestion is more of a trade off between cost and integration for which we value with much.	[2006-11-9 11:40:31]
[问：yuanli25]	现在30W的标准也即将出来了，也有公司退出了支持 30W 功率的兼容 PD，比如美信公司，请问 MCZ34670 既然支持非标准的供电设备，是否可以通过外围电路设计来增加供电的功率超过 13W, 能不能达到 30W？
[答：飞思卡尔]	MCZ34670 use external power MOSFET configuration. If input voltage range is within specification, theoretically is possible to change those external component eg. MOSFET, transformer ... to increase the system output power.	[2006-11-9 11:41:30]
[问：siufean]	演讲中曾经提到 PD 端电压受线缆影响，所以需要低电压保护，这个最低电压是 37 还是 42？
[答：飞思卡尔]	The Default Turn-Off Voltage (UVLO = VIN) is min. 30. Also there is an external UVLO Programming function by external resistor value. The programming range is 25V - 50V.	[2006-11-9 11:41:37]
[问：telsun]	一般以太网供电, 其用电设备电流应该控制在多大的范围内合适?
[答：飞思卡尔]	IEEE802.3af 规定 PD 功率在 13 瓦以下。	[2006-11-9 11:42:34]
[问：snowshadow]	已经建设的以太网能向网络终端提供电源吗？如果不能，如何改造?
[答：飞思卡尔]	The midspan PSE and Endpoint PSE could solve the problem.	[2006-11-9 11:43:41]
[问：zbq0204]	以太网在线供电 (PoE) 有些什么好处?
[答：飞思卡尔]	優點如下: 不需加一個AC/DC adaptor 安裝Access pioint, web cam, IP phone等不需另外拉AC電安裝方便可以經由UPS 在PSE 端增加系統可靠性等	[2006-11-9 11:44:13]
[问：zhangwq]	由何处理EMC带来的问题?
[答：飞思卡尔]	EMC是一个非常复杂的问题，它和产品设计使用的芯片，功能，电路板布局，走线方式，等等有关。您可以参考有关 EMC 的专著来降低 EMC 问题。当产品发现 EMC 问题后，需要使用专门的设备进行分析（扫频），然后定位问题芯片，引脚，或其他，再具体加以分析。找出解决方法。	[2006-11-9 11:45:34]
[问：tuoshi]	有人说PoE能促进网络的聚合, 你认为如何? POE 的生命力或前景如何?
[答：飞思卡尔]	POE 有很的潛力將來的 IP Phone, web cam, Access point 會逐漸轉換為支援 POE。	[2006-11-9 11:46:59]
[问：chpeng81]	有时候 PSE 需要提供更高的电压，比如 120V，飞思卡尔半导体公司有没有解决方案？
[答：飞思卡尔]	34670 design support the IEEE802.3af standard and the input voltage of 34670 supporting range now is over IEEE802.3af to max. 80V.	[2006-11-9 11:48:14]
[问：cai517]	与 Silicon 的 SI3400 相比，MCZ34670 有什么优势？
[答：飞思卡尔]	Apart from MCZ34670 being very competitive on price (depending on quantity), our device can yield a very efficient design in terms of power conversion efficiency. We are able to achieve close to 88% or better. Also our MCZ34670 has very useful features like Leading Edge Blanking and Adjustable Oscillator.	[2006-11-9 11:51:40]
[主持人：ChinaECNet]	各位观众，现在用户提问很踊跃，专家正在逐一回答。请耐心等待您问题的答案，同一问题请不要多次提交。	[2006-11-9 11:51:54]
[问：huangz]	在 POE 上, 如何解决脉冲和辐射保护问题？
[答：飞思卡尔]	在PD端的變壓器上要注意繞線部份儘量降低雜散電感及安裝接地遮蔽以降低幅射 PCB layout 要注意到 Power 部份與訊號部份做清楚的隔離。	[2006-11-9 11:52:20]
[主持人：ChinaECNet]	所有问题均已提交给Freescale公司的专家。座谈期间未回答的问题，Freescale公司专家也会逐一回答，并在中电网上公布，请大家注意收看。	[2006-11-9 11:52:20]
[主持人：ChinaECNet]	由于时间关系，本次中电网“在线座谈”马上就要结束了。虽然各位听众（网友）已与Freescale公司的专家讨论了许多问题，但是还有许多提问没有来得及进行交流。本次在线座谈结束后，中电网将请Freescale公司的专家继续答复所有的来自各位听众（网友）的提问，然后整理上载到中电网网站上，以便大家查阅。	[2006-11-9 11:52:34]
[问：hunklee]	在那里可以找到 MCZ34670 的规格书？
[答：飞思卡尔]	http://www.freescale.com/webapp/sps/site/prod_summary.jsp?code=MC34670&nodeId=0174400719	[2006-11-9 11:54:06]
[问：yuanli25]	在上电检测期间，因为要检测特征电阻，怎样估计整流桥在检测期间的影响？
[答：飞思卡尔]	您的问题非常好。我们提供了针对 MCZ34670 特征电子检测的一个计算公式，请您参考我们的应用笔记（Application Notes）AN3279，获得详细的信息。	[2006-11-9 11:54:41]
[问：jenired]	在以太网供电 (POE)，电源噪声会不会对数据传输有影响？如果有影响, 如何避免它对数据传输的影响?
[答：飞思卡尔]	在 IEEE802.3af 电源噪声对 PSE 的电源噪声有规定所以只要 PSE 符合这个规定应该对数据传输的影响有限。	[2006-11-9 11:55:27]
[问：siufean]	这个芯片可以定到样片吗？
[答：飞思卡尔]	Yes, this product is launched and we do provide sampling, please approach Freescale sales representative in your region.	[2006-11-9 11:56:14]
[问：wjarjar]	中跨和端跨 POE 在供电上有何不同? 为什么?
[答：飞思卡尔]	Mid span and end span are quite different. For End span, this would be the switch end where the power would be inserted by the PSE via either the spare pairs or the data pairs. For mid span, this would be a hub to extend the network wanting to use PoE but the switch does not provide such capability. The mid span inserts the power using the spare pairs only. Midspan PSE allows for the power to be supplied external to the ethernet. This provides both data and power on the twisted pair link segment without burdening each port of the Ethernet equipment when you need to provide power. So this offers a way to allow PoE to be added to older systems without replacing the switch hubs (with newer, PoE enabled units).	[2006-11-9 11:59:07]
[问：helen_hui_liu]	中跨馈电支持什么样的网络? 端跨馈电技术呢?
[答：飞思卡尔]	The Midspan PSE is located between the network switch/hub and the PoE Terminal(PD). The advantage of the standalone Midspan PSE is the simple extension of the existing network infrastructure. The Endpoint PSE equipment is integrated in the network switch/hub.	[2006-11-9 12:01:46]
[主持人：ChinaECNet]	在此，中电网特别感谢给予本次中电网在线座谈巨大支持的Freescale公司，特别感谢专门在线回答各位听众（网友）提问的Freescale公司的各位专家们，特别感谢各位听众（网友）积极热情的参与。	[2006-11-9 11:56:25]
[主持人：ChinaECNet]	祝大家事业有成、生活愉快！欢迎多提宝贵意见，欢迎关注中电网，下次再见。	[2006-11-9 11:58:03]
非在线问答：
[问：]	34670 是否可以支持 IEEE802.3AF PLUS?
[答：]	No
[问：]	飞思卡尔有 PSE 的解决方案吗？
[答：]	For PSE, currently we do not for our general product offering.
[问：]	I am using the 34670 Evaluation Board that is currently available, the it is fixed to 5V i want to have it to 3.3V is this possible? Where can i find this information?
[答：]	It is possible, yet it cannot be done by simply changing the resistor divider, since the transformer turn ratio primarily sets the output voltage. change the following components on the EVB to generate 3.3V: T1: POE13P_33B (Coilcraft) C10: 47nF R10: 470Ohm R13: 1.5k R9: 120Ohm C9: 4.7nF
[问：]	PSE 可提供 15.4W 的功率, 而 PD 只能接受 12.95W, 是否意味 POE 的效率一般只有 80% 左右?
[答：]	The 2.4W power difference is the margin for the cable power loss not the efficiency of the PD.
[问：]	飞思卡尔半导体对 RF 单片电路的研发设计都具体涉及到哪些?
[答：]	Out of scope, please refer to our future webcast.
[问：]	贵公司有 PSE 端的芯片吗? 是什么型号?
[答：]	For PSE, currently we do not for our general product offering.
[问：]	目前飞思卡尔的 POE 解决方案是什么样的？芯片量产了吗？
[答：]	We have MCZ34670 as our current PoE solution and is in mass production already.
[问：]	目前对于 POE 供电有没有超过 350mA 的国际标准？如500mA, 1A...
[答：]	At this moment the answer is no based on the current IEEE802.3af specification. However, the upcoming new IEEE802.3at standard is expected to supply 30W power which in turn should be able to support higher current.
[问：]	请问可以支持 CISCO 的 POE 标准么?
[答：]	Yes
[问：]	请问哪里有卖?
[答：]	Please contact Freescale local sales office or our web site for detials http://www.freescale.com.cn/products/powermanagement/mc34670.asp
[问：]	确切的讲在 POE 中，PSE 要比 PD 实现的难度大，现在市场上 PD 的集成实现方案比较多，贵公司也提出了自己的方案，但 PSE 的实现方案倒相对比较少？请问贵公司对 PSE 的集成解决方案有什么规划？
[答：]	For PSE, currently we do not for our general product offering.
[问：]	一般以太网供电, 其用电设备电流应该控制在多大的范围内合适?
[答：]	PD power is limited to 12.95W according to IEEE802.3af.
[问：]	以太网在线供电是如何工作? 一般来说, 有几种工作方式?
[答：]	You can go through our presentation again and check IEEE802.3af for details.

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