參數(shù)資料
型號： 73M1903C-IM
廠商： MAXIM INTEGRATED PRODUCTS INC
元件分類： 消費家電
英文描述： SPECIALTY CONSUMER CIRCUIT, QCC32
封裝： LEAD FREE, QFN-32
文件頁數(shù)： 30/45頁
文件大?。?/td> 459K
代理商： 73M1903C-IM
73M1903C
Modem Analog Front End
DATA SHEET
Page: 36 of 45
2005 TERIDIAN Semiconductor Corporation
Rev 3.4
APPENDIX A
73M1903C DAA Resistor Calculation Guide
TXAP1
RXAP
R1
R3
R1
R2
R3
R2
CBlock
RW
C1
TXAN1
ACTIVE
INDUCTOR
RING
DETECTOR
C1
Bead
Hook
Switch
Bridge
Diode
TIP
RING
RXAN
The following procedure can be used to approximate the component values for the DAA. The optimal
values will be somewhat different due to the effects of the reactive components in the DAA (this is a DC
approximation). Simulations with the reactive components accurately modeled will yield optimal values.
The procedures for calculating the component values in the DAA are as follows. First determine R1. For
a differential transmitter R1 is composed of 2 resistors that represent the difference in resistance between
the total winding resistance of the transformer and the reflected impedance, 600 . This value is usually
supplied by the transformer vendor. The DAA should be designed to reflect 600 when looking in at
TIP/RING. The transformer is normally a 1 to 1 turns ratio, the holding coil and ring detect circuit are high
impedance, and Cblock is a high value so in the frequency band of interest it is negligible. The sum of R2
and R3 is much greater than R1, and the output impedance of the drivers driving TXAP/TXAN are low,
therefore:
Rin 2 R1
.
RW Rohswitch
2 Rbead
.
RW is the sum of the winding resistance of both sides of the transformer. Measure each side of the
transformer with an Ohmmeter and sum them.
Rohswitch is the on resistance of the Off Hook Switch. Mechanical Relay switches can be ignored, but
Solid State Relays sometimes have an appreciable on resistance.
Rbead is the DC resistance of whatever series RF blocking devices may be in the design.
For Rin equal to 600 :
R1
600 RW Rohswitch
2 Rbead
.
2
To maximize THL (Trans-Hybrid Loss), or to minimize the amount of transmit signal that shows up back
on the Receive pins. The RXAP/RXAN pins get their DC bias from the TXAP/TXAN pins. By capacitively
coupling the R3 resistors with the C1 caps, the DC offset can be minimized from the TXAP/TXAN to the
RXAP/RXAN because the DC offset will be divided by the ratio of the R1 resistors to the winding
resistance on the modem side of the transformer.
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相關代理商/技術參數(shù)
參數(shù)描述
73M1903C-IM/F 功能描述:電信線路管理 IC Modem Analog Front End RoHS:否 制造商:STMicroelectronics 產品:PHY 接口類型:UART 電源電壓-最大:18 V 電源電壓-最小:8 V 電源電流:30 mA 最大工作溫度:+ 85 C 最小工作溫度:- 40 C 安裝風格:SMD/SMT 封裝 / 箱體:VFQFPN-48 封裝:Tray
73M1903C-IM/F1 功能描述:電信線路管理 IC RoHS:否 制造商:STMicroelectronics 產品:PHY 接口類型:UART 電源電壓-最大:18 V 電源電壓-最小:8 V 電源電流:30 mA 最大工作溫度:+ 85 C 最小工作溫度:- 40 C 安裝風格:SMD/SMT 封裝 / 箱體:VFQFPN-48 封裝:Tray
73M1903C-IMR/F 功能描述:電信線路管理 IC Modem Analog Front End RoHS:否 制造商:STMicroelectronics 產品:PHY 接口類型:UART 電源電壓-最大:18 V 電源電壓-最小:8 V 電源電流:30 mA 最大工作溫度:+ 85 C 最小工作溫度:- 40 C 安裝風格:SMD/SMT 封裝 / 箱體:VFQFPN-48 封裝:Tray
73M1903C-IMR/F1 功能描述:電信線路管理 IC RoHS:否 制造商:STMicroelectronics 產品:PHY 接口類型:UART 電源電壓-最大:18 V 電源電壓-最小:8 V 電源電流:30 mA 最大工作溫度:+ 85 C 最小工作溫度:- 40 C 安裝風格:SMD/SMT 封裝 / 箱體:VFQFPN-48 封裝:Tray
73M1903-EVM-600 功能描述:網(wǎng)絡開發(fā)工具 73M1903 w/Ppu & 600 Ohm Term-Usa & Japan RoHS:否 制造商:Rabbit Semiconductor 產品:Development Kits 類型:Ethernet to Wi-Fi Bridges 工具用于評估:RCM6600W 數(shù)據(jù)速率:20 Mbps, 40 Mbps 接口類型:802.11 b/g, Ethernet 工作電源電壓:3.3 V
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