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| 型号： | 73M2901CE-EVM-WW |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 17/30页 |
| 文件大小： | 0K |
| 描述： | BOARD DEMO 73M2901CE WORLDWIDE |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 1 |
| 系列： | * |
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UM_2901CE_026
73M2901CE Demo Board User Manual
4 73M2901CE EVM-WW Demo Board
It is possible to design a modem that can be used in virtually any country without the need to fit different
hardware for different countries’ standards. One of the more significant differences between countries is
the line impedance match that is required. This termination can be a concern since poorly matched
impedances will affect the network by increasing the reflections and crosstalk. Therefore, there are
different terminations required in different countries to match the equipment impedance to the local
network’s characteristics. Worldwide countries use three basic network models (see Table 8 and Table
9). In the U.S and North America, a 600 Ω resistive termination is used. Many other counties also use
this termination. In most of Europe, the primary termination is a complex AC impedance commonly called
“ETSI TS 203”. This is also used in other countries outside of Europe. The third network model is for
Australia and New Zealand. There are other concerns such as transmit levels, ring frequencies and
levels, call progress tone frequencies and cadence, and network protection. The first four of these are all
programmable through the 73M2901CE S-registers. The last can be taken care of by designing for the
most stringent specifications. Keep in mind that the overall cost of components will tend to be higher
since components with higher ratings will cost more. If Australia and New Zealand are on your list of
target countries, then design your protection for them.
Australia and New Zealand have higher isolation voltage requirements than other countries (3750VDC)
and require that the transformer be encapsulated. Any other devices that cross the isolation barrier, such
as opto-couplers, must also meet this requirement. They also have somewhat larger creepage and
clearance requirements to match their isolation requirements. The network input protection is now
standard, so finding components that that meet worldwide requirements are not too difficult. Input current
limiting and over-voltage protection are both universally required or advised. It is possible to pass PTT
testing in some cases without current limiting, but you put the integrity and survivability of your product at
jeopardy by not using it. Self-resetting PPTC fuses are now available that not only protect the product but
eliminate the need to replace parts if they are tripped.
4.1
Using the 73M2901CE0-EVM-WW Demo Board
The schematic in Figure 8 shows how to change the termination using the USR pins of the 73M2901CE to
control the AC termination network. The user pins control the analog switches that determine the
termination impedance. The user pins may have some other defined purposes if certain S register
settings are used.
Table 8: S-register Settings for Worldwide Modem Design
Termination
WW DAA 600 Ω
WW DAA CTR21
WW DAA Australia
Initialization String
ATS102-3S104-1S95-128S110-64S101+1S101-2S103-1
ATS102-3S104-1S95-128S110-64S101-1S101+2S103-1
ATS102-3S104-1S95-128S110-64S101-1S101-2S103+1
An example of this is the USR11 pin. If the continuous Caller ID mode is selected by setting the MSB of
S95, the USR11 pin will toggle during the Caller ID time. If you are using S95 in this mode, you should
set the modem termination just before going off hook to assure that you are configured with the correct
termination. Table 8 shows the initialization strings needed for the 73M2901CE Worldwide Demo Board.
If you choose to rearrange the USR controls in your design, the string settings will of course need to be
changed.
Table 9: Termination Impedance Network Values
Rev. 1.5
Termination
600 Ohm
ETSI TS 203
Australia
Component Values
600 Ω
750 Ω || 150nF + 270 Ω
820 Ω || 120nF + 220 Ω
17
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| 73M2901CE-IGV/F | 功能描述:电信线路管理 IC V.22bis Single-Chip Modem RoHS:否 制造商:STMicroelectronics 产品:PHY 接口类型:UART 电源电压-最大:18 V 电源电压-最小:8 V 电源电流:30 mA 最大工作温度:+ 85 C 最小工作温度:- 40 C 安装风格:SMD/SMT 封装 / 箱体:VFQFPN-48 封装:Tray |
| 73M2901CE-IGVR/F | 功能描述:电信线路管理 IC V.22bis Single-Chip Modem RoHS:否 制造商:STMicroelectronics 产品:PHY 接口类型:UART 电源电压-最大:18 V 电源电压-最小:8 V 电源电流:30 mA 最大工作温度:+ 85 C 最小工作温度:- 40 C 安装风格:SMD/SMT 封装 / 箱体:VFQFPN-48 封装:Tray |
| 73M2901CE-IM/F | 功能描述:电信线路管理 IC V.22bis Single-Chip Modem RoHS:否 制造商:STMicroelectronics 产品:PHY 接口类型:UART 电源电压-最大:18 V 电源电压-最小:8 V 电源电流:30 mA 最大工作温度:+ 85 C 最小工作温度:- 40 C 安装风格:SMD/SMT 封装 / 箱体:VFQFPN-48 封装:Tray |
| 73M2901CE-IM/F1 | 功能描述:电信线路管理 IC RoHS:否 制造商:STMicroelectronics 产品:PHY 接口类型:UART 电源电压-最大:18 V 电源电压-最小:8 V 电源电流:30 mA 最大工作温度:+ 85 C 最小工作温度:- 40 C 安装风格:SMD/SMT 封装 / 箱体:VFQFPN-48 封装:Tray |
| 73M2901CE-IMR/F | 功能描述:电信线路管理 IC V.22bis Single-Chip Modem RoHS:否 制造商:STMicroelectronics 产品:PHY 接口类型:UART 电源电压-最大:18 V 电源电压-最小:8 V 电源电流:30 mA 最大工作温度:+ 85 C 最小工作温度:- 40 C 安装风格:SMD/SMT 封装 / 箱体:VFQFPN-48 封装:Tray |
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