參數(shù)資料
型號(hào)： DS21Q55DK
英文描述： Quad T1/E1/J1 Transceiver Design Kit Daughter Card
中文描述： 四路T1/E1/J1收發(fā)器開發(fā)板子卡
文件頁數(shù)： 68/99頁
文件大?。?/td> 325K
代理商： DS21Q55DK
DS21Q50
Page 68 of 99
19.1.1 TERMINATION
The DS21Q50 is designed to be fully software-selectable for 75 ohm and 120 ohm termination without the need
to change any external resistors. The user can configure the DS21Q50 for 75 or 120 ohm receive termination by
setting the IRTSEL (CCR5.4) bit. When using the internal termination feature, the external termination resistance
should be120 ohms (typically two 60 ohm resistors). Setting IRTSEL = 1 will cause the DS21Q50 to internally
apply parallel resistance to the external resistors in order to adjust the termination to 75 ohms. See Figure 19-2
for details.
19.2 TRANSMIT WAVESHAPING AND LINE DRIVING
The DS21Q50 uses a set of laser–trimmed delay lines along with a precision Digital–to–Analog Converter
(DAC) to create the waveforms that are transmitted onto the E1 line. The waveforms meet the ITU G.703
specifications. See Figure 19-3. The user will select which waveform is to be generated by properly programming
the L2/L1/L0 bits in the Line Interface Control Register (LICR). The DS21Q50 can set up in a number of
various configurations depending on the application. See Table 19-1.
Table 19-1 LINE BUILD OUT SELECT IN LICR
L
2
1
0
0
0
0
75 ohm normal
1:2 step–up
0
0
1
120 ohm normal
1:2 step–up
0
1
0
75 ohm w/ protection resistors
1:2 step–up
0
1
1
120 ohm w/ protection
resistors
1
0
0
75 ohm w/ high return loss
1:2 step–up
1
0
1
120 ohm w/ high return loss
1:2 step–up
* NM = Not Meaningful (Return Loss value too low for significance)
** See separate application note for details on E1 line interface design
Due to the nature of the design of the transmitter in the DS21Q50, very little jitter (less then 0.005 UIpp
broadband from 10 Hz to 100 kHz) is added to the jitter present on TCLK (or source used for transmit clock).
Also, the waveform created is independent of the duty cycle of TCLK. The transmitter in the device couples to
the E1 transmit shielded twisted pair or COAX via a 1:2 step up transformer as shown in Figure 19-1. In order
for the devices to create the proper waveforms, the transformer used must meet the specifications listed in
Table
19-2
. The line driver in the device contains a current limiter that will prevent more than 50 mA (rms) from
being sourced in a 1 ohm load.
L
L
APPLICATION
TRANSFORMER RETURN
LOSS
*
NM
NM
NM
NM
RT
**
0 ohms
0 ohms
2.5 ohms
2.5 ohms
1:2 step–up
21dB
21dB
6.2 ohms
11.6 ohms
相關(guān)PDF資料
PDF描述
DS21Q55 Quad T1/E1/J1 Transceiver
DS21Q55N Quad T1/E1/J1 Transceiver
DS21S07A SCSI Terminator
DS21S07AE Terminator
DS21S07AS Terminator
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
DS21Q55N 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Quad T1/E1/J1 Transceiver
DS21Q58 制造商:DALLAS 制造商全稱:Dallas Semiconductor 功能描述:E1 Quad Transceiver
DS21Q58L 功能描述:網(wǎng)絡(luò)控制器與處理器 IC Quad E1 Transceiver RoHS:否 制造商:Micrel 產(chǎn)品:Controller Area Network (CAN) 收發(fā)器數(shù)量: 數(shù)據(jù)速率: 電源電流（最大值）:595 mA 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:PBGA-400 封裝:Tray
DS21Q58L+ 功能描述:網(wǎng)絡(luò)控制器與處理器 IC Quad E1 Transceiver RoHS:否 制造商:Micrel 產(chǎn)品:Controller Area Network (CAN) 收發(fā)器數(shù)量: 數(shù)據(jù)速率: 電源電流（最大值）:595 mA 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:PBGA-400 封裝:Tray
DS21Q58LN 功能描述:網(wǎng)絡(luò)控制器與處理器 IC RoHS:否 制造商:Micrel 產(chǎn)品:Controller Area Network (CAN) 收發(fā)器數(shù)量: 數(shù)據(jù)速率: 電源電流（最大值）:595 mA 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:PBGA-400 封裝:Tray
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。

采購需求

(若只采購一條型號(hào)，填寫一行即可)

發(fā)布成功！您可以繼續(xù)發(fā)布采購。也可以進(jìn)入我的后臺(tái)，查看報(bào)價(jià)

發(fā)布成功！您可以繼續(xù)發(fā)布采購。也可以進(jìn)入我的后臺(tái)，查看報(bào)價(jià)

*型號(hào) *數(shù)量 廠商 批號(hào) 封裝
添加更多采購

我的聯(lián)系方式

*
*
*