 |
Electronic Components Datasheet Search |
|
|
Electronic Components Datasheet Search |
|
LTC1543CG Datasheet(PDF) 8 Page - Linear Technology |
|
||||||||||||||||||||||||||||||
LTC1543CG Datasheet(HTML) 8 Page - Linear Technology |
|
|
8 / 20 page  8 LTC1543 APPLICATIONS INFORMATION Overview The LTC1543/LTC1544 form the core of a complete soft- ware-selectable DTE or DCE interface port that supports the RS232, RS449, EIA530, EIA530-A, V.35, V.36 or X.21 protocols. Cable termination may be implemented using the LTC1344A software-selectable cable termination chip or by using existing discrete designs. A complete DCE-to-DTE interface operating in EIA530 mode is shown in Figure 10. The LTC1543 of each port is used to generate the clock and data signals. The LTC1544 is used to generate the control signals along with LL (Local Loopback).The LTC1344A cable termination chip is used only for the clock and data signals because they must support V.35 cable termination. The control signals do not need any external resistors. Mode Selection The interface protocol is selected using the mode select pins M0, M1 and M2 (see the Mode Selection table). For example, if the port is configured as a V.35 interface, the mode selection pins should be M2 = 1, M1 = 0, M0 = 0. For the control signals, the drivers and receivers will operate in V.28 (RS232) electrical mode. For the clock and data signals, the drivers and receivers will operate in V.35 electrical mode. The DCE/DTE pin will configure the port for DCE mode when high, and DTE when low. The interface protocol may be selected simply by plugging the appropriate interface cable into the connector. The mode pins are routed to the connector and are left uncon- nected (1) or wired to ground (0) in the cable as shown in Figure 11. The internal pull-up current sources will ensure a binary 1 when a pin is left unconnected and that the LTC1543/ LTC1544 and the LTC1344A enter the no-cable mode when the cable is removed. In the no-cable mode the LTC1543/LTC1544 supply current drops to less than 200 µA and all LTC1543/LTC1544 driver outputs and LTC1344A resistive terminations are forced into a high impedance state. The mode selection may also be accomplished by using jumpers to connect the mode pins to ground or VCC. Cable Termination Traditional implementations have included switching resistors with expensive relays, or requiring the user to change termination modules every time the interface standard has changed. Custom cables have been used with the termination in the cable head or separate termina- tions are built on the board and a custom cable routes the signals to the appropriate termination. Switching the terminations with FETs is difficult because the FETs must remain off even though the signal voltage is beyond the supply voltage for the FET drivers or the power is off. Using the LTC1344A along with the LTC1543/LTC1544 solves the cable termination switching problem. Via soft- ware control, the LTC1344A provides termination for the V.10 (RS423), V.11 (RS422), V.28 (RS232) and V.35 electrical protocols. V.10 (RS423) Interface A typical V.10 unbalanced interface is shown in Figure 12. A V.10 single-ended generator output A with ground C is connected to a differential receiver with inputs A ' con- nected to A, and input C ' connected to the signal return ground C. Usually, no cable termination is required for V.10 interfaces, but the receiver inputs must be compliant with the impedance curve shown in Figure 13. The V.10 receiver configuration in the LTC1544 is shown in Figure 14. In V.10 mode switch S3 inside the LTC1544 is turned off.The noninverting input is disconnected inside the LTC1544 receiver and connected to ground. The cable termination is then the 30k input impedance to ground of the LTC1544 V.10 receiver. |
Similar Part No. - LTC1543CG |
|
Similar Description - LTC1543CG |
|
|
|
Link URL |
| Privacy Policy |
| ALLDATASHEET.NET |
| Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Contact us | Privacy Policy | Link Exchange | Manufacturer List All Rights Reserved©Alldatasheet.com |
| Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
|
Family Site : ic2ic.com |
icmetro.com |
English ▼
English
Chinese
German
Japanese
Russian
Korean
Spanish
French
Italian
Portuguese
Polish
Vietnamese
Indian
Mexican
British
New Zealand
