SP505AN SIPEX | Alldatasheet
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SP505/6/7APN/03 SP505, SP506, SP507 Application Note © Copyright 2000 Sipex Corporation The SP50x family of multi-protocol transceivers are designed for applications using serial ports in networking equipment such as routers, DSU/CSUs, multiplexors, access devices, and other networking equipment. This application note discusses and illustrates various configuration options, and other helpful hints about designing with the SP505 and the newer SP506 and SP507 products. These one-chip serial port transceiver products supports seven popular serial interface standards for Wide Area Network (WAN) connectivity. With a built-in DC-DC charge pump converter, the SP505 , SP506 and SP507 operate on +5V only. The seven drivers and seven receivers can be configured via software for RS-232, X.21, EIA-530, EIA-530A, RS-449, V.35, and V.36 interface modes at any time. Unlike other discrete solutions or other multi-chip transceivers, the SP505 , SP506 and SP507 require no additional external circuitry for compliant operation other than the charge pump capacitors. All necessary resistor termination networks are integrated within the SP505 , SP506 and SP507 , and are switchable when in EIA-530, EIA-530A, RS-449, V.35, V.36, and X.21 modes. The SP505 , SP506 and SP507 provide individual driver disable for easy DTE/DCE configurations. The SP507 offers four receiver enable lines for even easier DTE/DCE programmability. The newer SP506 is pin compatible with the SP505 except with improved AC performance. Refer to the SP505, SP506 and SP507 datasheets for electrical parameter and configuration details. Designing with the SP505, SP506, & SP507 Multi-Protocol Serial Transceivers
as a DTE in all serial communication applications. connector commonly used for EIA-530 and RS-232. can be used to select the physical layer interface. signals to the physically compliant connector. Figure 1. Signals and Connector Allocation Table
108 H *
141 L *
140 N *
125 J *
113 U *
113 W *
142 NN *
be implemented and active at one time.
Figure 2. SP506 DTE Configuration 1N5819, MBRS140T3, or equiv.
2 TXD(a)
14 TXD(b)
20 DTR(a)
23 DTR(b)
19 RTS(b)
4 RTS(a)
11 TXCE(b)
24 TXCE(a)
3 RXD(a)
16 RXD(b)
8 DCD(a)
10 DCD(b)
7 SIGNAL GND
13 CTS(b)
6 DSR(a)
22 DSR(b)
9 RXC(b)
5 CTS(a)
17 RXC(a)
15 TXC(a)
12 TXC(b)
SP505/6/7APN/03 SP505, SP506, SP507 Application Note © Copyright 2000 Sipex Corporation DCE Configuration to a DB-25 Serial Port The SP505, SP506 and SP507 can also be easily configured as a DCE in all serial communication applications. Figure 1 summarizes the usual signals used in synchronous serial communications. However when sourcing the signal by the DCE, the transceiver must be configured as a driver. The basic configuration shown in Figure 3 illustrates the connection to a DB-25 D-sub connector. Programmable DTE/DCE Configuration to a DB-25 Serial Port The SP505, SP506 and SP507 can also be conveniently configured so that the interface is programmable for either DTE or DCE. Extra attention must be paid to the direction of the signals since there may be bidirectional signals present. Figure 4 and 5 illustrate a connection to a DB-25 D-sub connector using the SP506 and SP507 , respectively. When bidirectional signals are needed, this usually means a driver and receiver are half-duplexed together. In other words, the driver outputs are connected to the receiver inputs. This requires the driver outputs to be disabled and at a high impedance state. The receiver does not require a disable function as long as the inputs are high enough impedance so that the driver signals are not attenuated. A half-duplexed receiver without a disable function will still produce a signal at its output when the driver is active and communicating with the receiver at the other end of the cable. This signal can be ignored unless the receiver output is tied to the driver input. If this is the case, then the receiver output should a buffered with a latch or 2:1 mux in order to direct the driver input or receiver output into the HDLC device. The SP507 has additional receivers with enable lines for easier DTE/DCE implementation. The SP505, SP506 and SP507 can be configured on the equipment as either DTE or DCE to the DB-25 connector. For the illustration on Figure 4, DTE is used with the SP506 . Since only a DB-25 connector is used as the equipment's serial port, daughter cables are still needed for the other connector types. In addition, to support DCE on this serial port, crossover cables are used. Thus, the equipment will need to provide a DTE V.35 cable and a DCE V.35 cable, for example. Crossover cables merely reroute the signals to the appropriate connector pin assignment. For DTE in V.35 mode, pins P and S are used for Transmit Data (ITU#103), and pins R and T are used for Receive Data (ITU#104). Pins P and S are connected to the driver outputs since they are sourced from the DTE. Pins R and T are connected to the receiver inputs since they are sourced for the DCE. To convert the serial port to a DCE configuration, the crossover cable swaps the signals to those pins. Specifically, the DB-25 will have pins 2 and 14 connected to the driver and pins 3 and 16 connected to the receiver. This is a normal DTE allocation. However, by the time these signals reach the other end of the cable to the ISO2593 V.35 connector, the pins 2 and 14 now go to R and T, respectively. Pins 3 and 16 on the DB-25 side now go to pins P and S, respectively. Therefore, pins R and T are now generating the data and thus, connected to the driver output. Similarly for pins P and S, now connected to the receiver inputs. The configuration on Figure 5 uses the SP507 in a popular DTE/DCE configuration. The TxC signal is half-duplex and bidirectional. The DCE_ST driver is active during DCE mode while the DTE_ST receiver is active during DTE mode. The STEN and SCTEN enable lines are connected together for common DCE/DTE control. Similarly with the RL/DCD pair and the LL/TM pair. The DCD signal is used for this driver labelled RL in this case. The Remote Loopback function is not available in this configuration. The same goes for the Test Mode function where the TM receiver is used for Local Loopback when in DCE mode. On-Board Programmable DTE/DCE Configuration (Without Crossover Cables) DTE/DCE programmability can also be achieved without using crossover cables. Instead, the selection can be designed in the circuitry. This requires a bidirectional serial port for all signals, not just TxC and DCD. An "on-board" solution would need to have circuitry allocated for DTE and circuitry allocated for DCE. The transceiver portion would need to address disable functions, low leakage currents, and specific timing issues when joined together in a half-duplex configuration.
Figure 3. SP506 DCE Configuration 1N5819, MBRS140T3, or equiv.
7 SIGNAL GND (#102)
Figure 4. SP506 DTE/DCE Programmable Configuration 1N5819, MBRS140T3, or equiv.
2 TXD(a)/RXD(a)
14 TXD(a)/RXD(b)
20 DTR(a)/DSR(a)
23 DTR(b)/DSR(b)
19 RTS(b)/CTS(b)
4 RTS(a)/CTS(b)
11 TXCE(b)/TXC(b)
18 LL/TM
24 TXCE(a)/TXC(a)
3 RXD(a)/TXD(a)
16 RXD(b)/TXD(b)
8 DCD(a)/RL or DCD(a)**
10 DCD(b)/DCD(b)
13 CTS(b)/RTS(b)
6 DSR(a)/DTR(a)
22 DSR(b)/DTR(b)
9 RXC(b)/TXCE(b)
5 CTS(a)/RTS(a)
17 RXC(a)/TXCE(a)
SP505 will not be in use during DCE mode in this case. I/O Lines represented by double arrowhead signifies a bi-directional bus. Optional bi-directional line; if RL (#140) is used, the driver output, RL(a), can go directly to pin. 21, Remote Loopback, of the DB-25. The RLEN enable pin, if RL is used, can be permanently enabled by tying it to GND.
25 TM/LL
Figure 5. SP507 DTE/DCE Programmable Configuration (Similar configuration to competitor's 3-chip solution.) 1N5819, MBRS140T3, or equiv.
- - Driver applies for DCE mode only on pins 15 and 12 for signal TxC.
Receiver applies for DTE mode only on pins 15 and 12. Driver applies for DCE mode only on pins 8 and 10 for signal DCD. Receiver applies for DTE mode only on pins 15 and 12. applies for DTE mode only on pin 18. I/O Lines represented by double arrowhead signifies a bi-directional bus.
1 SHIELD GND
Figure 6. Complete DTE/DCE Programmable Serial Port w/o Crossover Cables 1N5819, MBRS140T3, or equiv. 1N5819, MBRS140T3, or equiv.
SP505/6/7APN/03 SP505, SP506, SP507 Application Note © Copyright 2000 Sipex Corporation The SP505, SP506 and SP507 can be easily designed to support this type of configuration. Figure 6 shows a typical circuit illustrating two SP506 devices connected in a half-duplex configuration. The top circuit is dedicated to DTE and the bottom SP506 is dedicated to DCE. Note that only one device is active at any given time. For DTE, the decoder for the DCE device should be off (0000), and vice versa. During the shutdown or off state of the SP506 , the driver output typically draws 100µA of leakage current. Even with the maximum SP506 leakage current of 500µA, the receiver input impedance would only change by 500Ω . This is important for RS-232 since the input voltage range can be up to 15V and the typical RS-232 receiver input impedance is 5kΩ . For V.11 differential receivers, the maximum range is +7V and typical input impedance is 10kΩ . Thus for V.28 receivers, the drivers would be effectively driving into 5kΩ in parallel with the disabled receiver with 10kΩ input impedance. The resultant impedance is 3.3kΩ . For V.11 mode, the drivers will drive into either a terminated receiver of 120Ω or unterminated receiver at 3.9kΩ. These two values in parallel with the disabled 10kΩ receiver will yield 118Ω and 2.8kΩ , respectively, and will not degrade the V.11 driver performance. The receiver outputs are typically at 1µA when disabled. The SP505 , SP506 and SP507 adds convenience by incorporating the V.11 and V.35 termination resistors inside the device. For this type of 2-chip DTE/DCE configuration, the termination resistors would need to be disabled along with the receivers. A "0000" code into the SP505 and SP506 will automatically disable all termination networks as well as the transceivers. A "111" code into the SP507 performs the same function. In the shutdown mode, the IC will draw less than 10mA of supply current. Adding Additional Transceivers To support additional signals, the SP522 can easily attach onto the SP505 , SP506 or SP507 charge pump outputs, V DD and VSS. The SP522 adds two drivers and two receivers for supporting other signals such as RI and RL. In Figure 7, the SP522 is hardwired for RS-423 or ITU-T V.10 mode. This allows for the support of RI and RL in RS-449 or V.35 modes if necessary. Schottky Diode on the SP50x Sipex requires the installation of a Schottky rectifier placed between the VCC and VDD pins of the SP50x charge pump, where the anode is connected to VCC and the cathode is connected to VDD . It is required to bootstrap the charge pump's internal circuitry during power off conditions in presence of signals or voltages through the receiver inputs or driver outputs. When placed in parallel with the charge pump capacitor, the diode will allow some of the V CC current to flow into the VDD regions of the device, which will partially bias the VDD charged regions before the device charge pump is fully functioning. This prevents biasing of VDD from other sources such as through the driver outputs or receiver inputs, typical of serial port connections to other powered-on equipment. Once the charge pump oscillator starts up and becomes functional, current flows from V DD back into VCC through the capacitor, ensuring that a rapidly rising VDD does not rise too quickly above the V CC regions before the VCC regions have become fully charged. The main characteristics of the Schottky diode necessary for this application is the forward voltage. The VF of the 1N5819 type, which is the diode recommended, is 0.6V @ 1A. Surface mount versions are available from Motorola . The MBRS130T3 from Motorola is used with our SP505, SP506 , and SP507 evaluation boards. Other options are MBRS140T3 or MBRS130LT3 , which are all in a "403A-03 SMB" package. The end-to-end length is 5.40mm typical and the width is 3.55mm typical. Motorola also offers the Powermite ™ line, which offers the Schottky rectifiers in a 1.1mm height, 3.75mm length, and 1.90mm width surface mount package. The part numbers recommended are MBRM120LT3, MBRM120ET3, and MBRM140T3. Specifics can be found in Motorola Semiconductor's web site (http://mot-sps.com/products/index.html). The Schottky rectifiers can be found in the discrete rectifier section and datasheets can be downloaded after searching for the part number.Powermite™ is a trademark of Motorola.
Figure 7. Adding the SP522 to the SP507 in a DTE/DCE Programmable Configuration 1N5819, MBRS140T3, or equiv.
- - Driver applies for DCE mode only on pins 15 and 12 for signal TxC.
Receiver applies for DTE mode only on pins 15 and 12. Driver applies for DCE mode only on pins 8 and 10 for signal DCD. Receiver applies for DTE mode only on pins 15 and 12. applies for DTE mode only on pin 18. I/O Lines represented by double arrowhead signifies a bi-directional bus.
the full 4,000 feet of Category 3 or similar type cable. especially at higher frequencies. cables will have 3-5pF per foot. evaluation board, which was configured as the DTE. 1:1 data bit stream that is sent back through the cable. Figure 8. SP507 Cable Length Versus Throughput Circuit Configuration Cable Length used: 6ft. to 156ft.
Figure 27. SP507 TxCE at 12MHz over 86ft. caused by various environmental effects. and resulting in bit errors. receiver input sensitivity is higher. distance versus speed allowance in the application.
SP505/6/7APN/03 SP505, SP506, SP507 Application Note © Copyright 2000 Sipex Corporation the power supply unit and radiated out to the environment. For serial port datacom applications, both emissions and immunity must be carefully considered during the design-in phase. The conducted emissions in the most single supply interface transceivers are generated from the internal charge pump. Although the charge pump is enhanced over previous generation pumps, the SP506 and SP507 charge pump architecture will inherently have small ripples on the V DD and VSS outputs. The ripples are due to the switching of the internal charge pump transistors that are transferring energy. The charge pump oscillates at 20kHz in standby mode (without loads to the drivers) and will automatically increase frequency to 300kHz when loaded. The ripples will coincide with the oscillator frequency. The driver output circuitry receives biasing from the charge pump outputs, V DD and VSS , for the V.28 and V.10 bipolar voltage swings. The VDD or VSS supply ripple could be superimposed onto the driver outputs, depending on the ripple amplitude. Larger capacitor values will suppress the ripple of the pump and thus, minimize the ripple amplitude on the data lines. For the SP505 , SP506 , and SP507 , the amplitude of the ripple is below 100mV when using 22µF pump capacitors (refer to Figure 34). Depending on the application requirements, EMI/EMC filtering may be needed. The SP506 and SP507 are usually not affected by radiated disturbance nor do they emit radiated noise/interference. But a shielded enclosure (Faraday Cage) will help the immunity from radiated disturbance as well as emissions of radiated noise. Conducted noise can be surpressed by using ferrite beads, low pass filters using RC circuits, inductor circuits, or common mode chokes on the signal lines. One surface mount common-mode choke (CMC) designed for data signaling applications in the 10Mbps to 15Mbps band is TDK's ZJYS51R5-4P. This 8-pin SOIC package contains a two pairs of inductors for two differential signals. Since clock and data are switching most frequently, the number of pairs needed are two for DTE (TxD and TxCE drivers) or three for DCE (TxD, TxCE, TxC drivers), which means one IC for DTE and two ICs for DCE. Refer to Figure 31 for connection and to TDK's datasheet for the ZJYS51R5-4P CMC. (http://www.tdk.co.jp/tefe02/e971_zjys.pdf) Semtech's SMDA15C-7 is used in Figure 30 to protect the handshaking signals. Since the SMDA15C-7 only provides protection for seven lines, the SMDA15C-5 is used for the remaining lines. Both are 8-pin SOIC packages. Other configurations or manufacturers can be used. Refer to the TVS datasheets. (http://www.semtech.com/pdf/tvs/lcda15c6.pdf) Figure 6 also shows optional TransZorbs ™ or TVS devices on the SP506 to further protect the serial port from any ESD or overvoltage transients that may occur in any application. The SP505 , SP506 and SP507 are internally rated for 8kV based on Human Body Model and 2kV Air Discharge per IEC1000-4-2. Adding transzorbs to the I/O lines will protect the serial port to over 15kV of ESD transients per IEC1000-4-2 Air Discharge and 8kV per Contact Discharge. The TVS devices on the driver inputs and receiver outputs are included for hot-insertion of the interface module/board applications. The internal junction of the SP505 , SP506 and SP507 receiver inputs and driver outputs are similar to the I-V curve on Figure 28. However, TVS devices are always recommended where ever possible as it is difficult to predict transient induced phenomena in any environment. It is also important to know that these TVS devices are also specified for IEC1000-4-4 Electrical Fast Transients and IEC1000-4-5 Surge (Lightning) protection. Refer to the TVS datasheets from Semtech for details (www.semtech.com). Electromagnetic Interference is also a concern for networking equipment. The EMI noise is cause by radiated emissions or power-line conducted emissions from the system. The equipment has to be characterized for both immunity and emissions. Immunity is the system's tolerance to incoming interference or disturbances generated from outside sources. Emissions are the system's own generation of these types of disturbances. Specifically, the documents EN61000-4-3 and EN61000-4-6 pertain to Radiated electric field test and Line Conducted electric field test, respectively, for immunity. The EN55022 specification pertains to emissions and specifies Line Conducted Emission, which are noise or disturbances generated from a power supply unit, conducted in the cables; and Radiated emissions, which pertain to noise or disturbances generated by
regular non-filtered connectors. Various filter types are available with these connectors. Figure 31. Common-Mode Choke Circuit with Drivers AMPLIMITE ™ is a trademark of AMP Inc.
in the Design Guide for Multi-Protocol Serial Ports. inputs have additional access points for convenience. points for convenience at each receiver. receiver enable lines and the mode select pins. active LOW and have internal pull down resistors. pull-down defines a LOW state. Figure 36. SP507EB Schematic
2 SD(a)
14 SD(a)
20 TR(a)
23 TR(b)
19 RS(b)
4 RS(a)
11 TT(b)
18 LL(a)
15 SCT(a)
12 SCT(b)
24 TT(a)
3 RD(a)
16 RD(a)
13 CS(b)
6 DM(a)
22 DM(b)
9 RT(b)
5 CS(a)
17 RT(a)
8 RR(a)
10 RR(b)
25 TM(a)
21 RL(a)
Figure 38. SP507 Evaluation Board Layout
compliancy to their respective ITU specifications.
6.3.1.1 Generator open circuit output voltage
3.9kΩ resistor to ground (point C).
6.3.1.3 Generator output rise/fall time
and with a 450Ω resistor load to ground.
6.3.1.4 Generator polarities
Figure 39. V.10 Driver Open Circuit Voltage
6.3.1.2 Generator terminated output voltage
terminated with a 450Ω resistor to ground. Figure 40. V.10 Driver Terminated Voltage Figure 41. V.10 Driver Transition Time
6.3.2.1 Generator open circuit output voltage
resistor between points A and points B.
6.3.2.3 Generator output rise/fall time
6.3.2.4 Generator polarities
or OFF for control circuits. Figure 42. V.11 Driver Open Circuit Voltage
6.3.2.2 Generator terminated output voltage
Figure 43. V.11 Driver Output Terminated Voltage Figure 44. V.11 Transition Time
6.3.3.1 Generator open circuit output voltage
terminated with a 3kΩ resistor to ground.
6.3.3.5 Receiver maximum shunt capacitance
at point A to point C (t2) is measured and recorded. the same signal through the 1.2kΩ resistor. Figure 45. V.28 Driver Open Circuit Voltage Figure 46. V.28 Driver Terminated Voltage Figure 47. V.28 Transition Time Figure 48. V.28 Receiver Effective Shunt Capacitance
6.3.4.1 Generator open circuit output voltage
resistor between points A and points B. Figure 49. V.35 Driver Open Circuit Voltage
6.3.4.2 Generator terminated output voltage
connected in series between point A and point B. Figure 50. V.35 Driver Terminated Voltage
6.3.4.3 Generator output rise/fall time
the two series resistors to ground.
6.3.4.4 Generator polarities
or OFF for control circuits. Figure 51. V.35 Transition Time also be furnished upon request. Please contact Sipex Applications for details.
Figure 52. Front Cover of the CTR1/CTR2 Test Report for the SP505
Figure 53. Front Cover of the CTR1/CTR2 Test Report for the SP507
SP505/6/7APN/03 SP505, SP506, SP507 Application Note © Copyright 2000 Sipex Corporation
ORDERING INFORMATION
Multi-Protocol Transceiver Products Model Temperature Range Package Types Evaluation and Retrofit Boards Model Description Evaluation Kits (Boxed with SP5xxEB, Product Datasheet, Application Note) Model Description Corporation SIGNAL PROCESSING EXCELLENCE Sipex Corporation reserves the right to make changes to any products described herein. Sipex does not assume any liability arising out of the application or use of any product or circuit described hereing; neither does it convey any license under its patent rights nor the rights of others. Sipex Corporation Headquarters and Sales Office
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