SP503AN

SP503AN SIPEX | Alldatasheet

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Due to its flexibility and programmability, the SP503 has been finding its way into many new networking products. The SP503 offers an excellent replacement for discrete solutions on X.25 implementations for frame relay systems, multi-protocol routers and other WAN products where many designs run various modes such as RS-232, RS-422, V.35 or V.36. For RS-232, the older bipolar 1488 and 1489 parts, or even the newer MAX230 or SP230 series have traditionally been used. For RS-422 or RS-485, the 26LS31, 26LS32, 3488, and 3489 have been seen in many designs. These parts have been also used for V.35 but with external termination resistors. For a typical design, four RS-232 chips would be used for a complete RS-232 port, four RS-422 chips for an RS-422 port and four chips for V.35 with an external resistor network. Port programma- bility would require relays or switches so that software lines can control whether RS-232 is active or RS-422 is active. The relays increase board capacity as well as cost to the design. The SP503 solves board space and cost problems by offering a single packaged part that supports various protocols and also offers software programmability to the port. n DTE and DCE configurations with the SP503 n Connecting the SP503 to a DB-25 connector in DTE and DCE modes n Implementing V.35 with the SP503 n Creating extra single-ended and differential channels with the SP503 using the SP310A and SP485 n Using external supplies with the SP503 SP503 Application Note Typical discrete solution vs. the SP503

DTE and DCE configurations with the SP503 The SP503 has designated signals such as "Trans- mit Data", "Clear-to-Send", etc.which design- ers can easily allocate the appropriate SP503 transceivers for the corresponding signals. The data signals specified in the EIA standards and CCITT are referenced in the SP503 datasheet as DTE. Some customers have wondered if they can use the SP503 for DCE applications. Although it can be confusing at first glance, the DCE implementation is the mirror image of the DTE side. For the DTE, TxD is a driver which drives the data to RxD, a receiver, on the DCE side. TxC or TT is a driver on the DTE side which drives the clock signal to the RxC re- ceiver on the DCE side. The next three pages illustrate the CCITT signal allocations from the SP503 in either DTE or DCE to the DB-25 connector. As shown, it is possible to use a DB-25 connector for the vari- ous protocols offered by the SP503 . DB-25 Connector Pin Assignments for Various Protocols DB-25 Pin # RS-232 EIA-530 RS-449 RS-422 V.35 V.36 1 shield shield shield shield CCITT# 101 CCITT# 101

2 TxD TxD(A) SD(A) T(A) 103(A) 103(A)

3 RxD RxD(A) RD(A) R(A) 104(A) 104(A)

4 RTS RTS(A) RS(A) C(A) 105 105(A)

5 CTS CTS(A) CS(A) – 106 106(A)

6 DSR DSR(A) DM(A) – 107 107(A)

7 Signal GND Signal GND Signal GND Signal GND 102 102

8 DCD RLSD(A) RR(A) I(A) 109 109(A)

9 – RxC(B) RT(B) – 115(B) 115(B) 10 – RLSD(B) RR(B) I(B)\` – 109(B) 11 – TxC(B-DTE) TT(B) – 113(B) 113(B)

12 DCD (2nd) TxCC(B-DCE) ST(B) S(B) 114(B) 114(B)

13 CTS (2nd) CTS(B) CS(B) – – 106(B)

14 TxD (2nd) TxD(B) SD(B) T(B) 103(B) 103(B)

15 TxCC (DCE) TxCC(A-DCE) ST(A) S(A) 114(B) 114(B)

16 RxD (2nd) RxD(B) RD(B) R(B) 104(B) 104(B)

17 RxC RxC(A) RT(A) – 115(A) 115(A)

18 LL LL LL – – 141

19 RTS (2nd) RTS(B) RS(B) C(B) – 105(B)

20 DTR DTR(A) TR(A) – – –

21 RL RL RL – – 140

22 RI DSR(B) DM(B) – – 107(B)

23 SRS DTR(B) TR(B) – – –

24 TxC (DTE) TxC(A-DTE) TT(A) – 113(A) 113(A)

DTE-DCE flexibility with the SP503 on a DB-25 serial port DB-25 Connector TxD TxC DTR RTS RxD RxC CTS DCD TxD TxC DTR RTS RxD RxC CTS DCD RDEC0 RDEC1 RDEC2 RDEC3 TDEC0 TDEC1 TDEC2 TDEC3 2 3 4 5 12 11 10 9 2345 1 2 1 1 1 09 DSR RI SCT LL RL ST Quad 2:1 Mux 4BSEL "0" = DTE "1" = DCE SCC SD (A) SD (B) TT(A) TT(B) TR (A) TR (B) RS (A) RS (B) RT (A) RT (B) RD (A) RD (B) CS (A) CS (B) RR (A) RR (B) DM (A) DM (B) SCT (A) SCT (B) IC(A) IC(B) LL(A) LL(B) ST (A) ST (B) SP503 DTE Config. SP503 DCE Config. RL (A)47 225 21424 11419 TxD TxC DTR RTS RxD RxC CTS DCD DSR RI SCT LL RL ST SD (A) SD (B) TT(A) TT(B) TR (A) TR (B) RS (A) RS (B) RT (A) RT (B) RD (A) RD (B) CS (A) CS (B) RR (A) RR (B) DM (A) DM (B) SCT (A) SCT (B) IC(A) IC(B) LL(A) ST (A) ST (B) RL (A) LL(B)

Driver / Receiver Connections to a DB-25 Connector DTE Mode Male Connector TxD Drivers Receivers DTR RTS TxC SP503CF RxD RxC CTS DSR DCD RI SCT RL LL ST to pin 22 for non-RS-232 RI used for RS-232 only

Driver / Receiver Connections to a DB-25 Connector DCE Mode TxD Drivers Receivers DTR RTS TxC SP503CF RxD RxC CTS DSR DCD RI SCT RL LL ST Female Connector to pin 22 for non-RS-232 TxD(A) TxD(B) TxC(A) TxC(B) RTS(A) RTS(B) DTR(A) DTR(B) LL RL RxD(A) RxD(B) DSR(A) CTS(A) CTS(B) RxC(A) RxC(B) SCT(A) SCT(B) RI DCD(A) DCD(B)* 49 * The non-inverting LL driver output is not a valid driver output for RS-449 and EIA-530.

SP503 V.35 External Termination Resistors V.35 implementation requires external resistors to be connected to the driver outputs and re- ceiver inputs. The resistors are needed for reducing signal levels and maintaining input and output impedance levels that conform to CCITT Recommendation V.35. The drawings below offer both receiver input termination and driver output termination configurations that will comply to V.35. As you may know, the termination resistors are for V.35 mode only and have to be disconnected when another mode is programmed. There are a few ways to connect and disconnect the net- work. One method is to add a daughter-card option slot onto the main printed circuit board where the SP503 is mounted. This allows the user to add a mini-PC card that contains the V.35 network to be connected to the driver outputs and receiver inputs. Another method is to implant the V.35 network into a cable if the user requires conversion cables to switch from one protocol to another. For example, if the serial port has a DB-25 connector and requires an ISO-2593 connector for V.35; a DB-25 to ISO-2593 conversion cable containing the V.35 network is connected to the port. Of course this method will not allow program- mability to the serial port if the user wants to run various protocols to that port. To actively switch protocols by software control, you can use ana- log switches or relays. Sipex recommends us- ing low-ON resistance analog switches, such as Siliconix DG643 © analog switches for the driver outputs, and solid-state relays such as the AT&T LH1514 © for the receiver inputs. See opposite page for an example of the SP503 V.35 configu- ration. For other termination networks, please consult the factory. 50Ω 50Ω 120Ω A B ZSOURCE = 97Ω ZSC = 148Ω [90Ω to 110Ω ] [135Ω to 165Ω ] 232Ω 232Ω 200Ω 200Ω 107Ω A B 100Ω LOAD-5V ±5% ZSOURCE = 96Ω ZSC = 154Ω [50Ω to 150Ω ] [135Ω to 165Ω ] V D = 0.55V V DC_OFF = 0.0V [+0.44V to +0.66V] [-0.6V to +0.6V] Typical values V.35 Receiver Input Termination Resistor Network V.35 Driver Output Termination Resistor Network

SP503 Switching Configuration for V.35 Implementations

• Switches are Siliconix DG643DY analog switches. • Solid-State Relays are AT&T, LH1514 .
• Resistors are 1/8W, 1% tolerance.
• External Supplies necessary are: V cc = +5V, V+ = +12V (for V+ on the DG643DY) and Vn = -5V. Receivers TxD Drivers DTR RTS TxC SP503CF RxD RxC CTS DSR DCD RI SCT RL LL ST V+ V-+5V Driver Outputs & Receiver Inputs are in DTE mode. to pin 12 of the 74LS11 to pin 12 of the 74LS11 to pin 12 of the 74LS11 74LS11 74LS11 74LS11 (3-Input AND Gate) RxC (115) A B RxD (104) A B A B A B TxD (103) A B TT (113) TxCC (114) A B to pin 6 of the 74LS11 74LS11 LH1514 74LS11 LH1514 7 LH1514 7 +12V 50Ω 50Ω 120Ω 6 50Ω 50Ω 120Ω 50Ω 50Ω 120Ω 12 5 10 14 12 5 1014 DG643 DG643 200Ω 200Ω 232Ω 232Ω -5V 107Ω to V-+12V 12 5 10 14 12 5 1014 DG643 DG643 +12V 200Ω 200Ω 232Ω 232Ω -5V 107Ω 12 5 10 14 12 5 1014 DG643 DG643 +12V +12V 200Ω 200Ω 232Ω 232Ω -5V 107Ω +5V 21 21/4 74LS11 +5V 4 6 RDEC1 & TDEC1 RDEC2 & TDEC2 RDEC3 & TDEC3 (pins 3 & 11) (pins 4 & 10) (pins 5 & 9) to pin 6 of the 74LS1174LS11 74LS11

Typical Applications Questions on the SP503 Can the SP503 be used with external power supplies? If so, is there a power-up sequence? The internal charge pump can be bypassed through external supplies to VDD and VSS. The external voltage should be +10V for VDD and -10V for VSS. The tolerance is ±5%. The absolute minimum limit for the external supplies is ±7V and the absolute maximum limit is ±10.5V. The SP503 does require a power-up sequence of +10V, +5V, -10V for proper operation. Addi- tional external circuitry will be required for the correct sequencing. Consult factory for details. What is the maximum input voltage applied to the receiver input without damaging the SP503 ? The receiver inputs can tolerate up to ±16V in any protocol without latching up the device. Since RS-232 ranges from ±5V to ±15V; the SP503 is well within the accepted range. It may be worthwhile to include 15V clamping diodes or transient voltage suppressors so that the re- ceiver input will be held below ±15V. What is the maximum short-circuit voltage that can be applied to a SP503 driver output? The driver outputs can be shorted up to ±16.0V without causing damage to the driver. Between the ±16V range, the SP503 adheres to the RS- 232 short circuit current limit of 100mA and to the RS-422/RS-423 limit at 150mA. Again, transient voltage suppressors or clamping diodes will protect the SP503 if exceeding the ±16V range is possible. What is the state of the SP503 drivers and receivers when the device is addressed with 0000? The SP503 drivers are in a high impedance(over 1M Ω ) tri-state condition when "0000" is ad- dressed. The receivers are not tri-stated and the outputs are undefined. This means that they could be floating to either a high or low level depending on the previous state of the receiver input prior to the 0000 addressing change. The receiver input impedance is at 15kΩ for "0000". Can the SP503 be programmed for 7 drivers and 7 receivers in RS-423 mode? The SP503 can be switched to RS-423 mode by programming TDEC 3, TDEC2, TDEC1, TDEC0 to "1000" for the drivers and RDECX to "1000" for the receivers. However, external supplies must be used in order to drive RS-423. The internal charge pump can only support up to three RS-423 drivers and three RS-423 receivers. What is the power dissipation in the SP503 and in which mode does it consume the most power? The SP503 dissipates approximately 400mW to 1.4W depending on the protocol. RS-485 mode consumes the most power at 1.4W. For worst case power dissipation, all seven drivers were driven with a TTL signal and the outputs were looped back into the receiver inputs to generate a TTL output. All drivers and receivers were active. MODE P D RS-232 0.418W RS-422 0.970W RS-485 1.382W RS-449 0.959W EIA-530 0.959W V.35 1.055W What is the state of the SP503 drivers and receivers when the device is addressed with 1111? The address for "1111" is not used in the SP503 . If the SP503 is programmed for "1111", the drivers are approximately 1.0V and at a high impedance (approx. 9MΩ ). The receivers are not tri-stated and the outputs are undefined. All receiver inputs are at 15kΩ input impedance. The SP503 can receive a "1111" address while V CC is off. The supply current is approximately 50mA (V CC = +5V) while the address is at "1111". In the RS-232 signal assignments for the DB-25 connector, where does the SP503 account for Test Mode (TM) ? For most RS-232 applications, the signals com- monly used are TxD, TxC, RxD, RxC, RTS, CTS, DSR, SG, DCD, DTR and Frame Ground.

In DTE mode; TxD, TxC, RTS, DTR are the drivers and RxD, RxC, CTS, DSR, DCD are the receivers. Since there are seven drivers and seven receivers in the SP503 , the designer can easily use the SP503 for the above signals. Other RS-232 applications will support diagnostic func- tions such as LL (driver), RL (driver), and TM (receiver) which may or may not require extra transceivers depending if other signals are not used. Since Test Mode (TM) is a receiver for DTE designs, the Ring Indicator (RI) receiver in the SP503 (pin 21) can be used for TM if RI is not used. If all the available drivers and receivers are used in the SP503 , then another RS-232 trans- ceiver can be added. See page 230 and 231 for suggestions on adding Sipex's RS-232 and RS-485 transceivers. Are the Schottky diodes used from Vcc to Vss and from Vdd to C2- in the SP502 necessary for the SP503 ? Sipex has incorporated the Schottky diodes (needed with the SP502 ) into the SP503 in order to protect against potential start up problems due to fast rate of rise on VCC (≥1V/µs) and overvolt- age to the TTL inputs. However, a negative voltage (V in ≤ -5V) applied to the receiver inputs while the SP503 is powered off will cause start- up problems to the charge pump. In order to guard against this condition, an external Schottky diode should be placed from V CC to VDD to minimize VCC current injection into the IC sub- strate and allow the charge pump to operate properly. See page 203 Figure 6 - Typical Operating Circuit, for diode connection schematic. Can the SP503 be configured for V.36? CCITT Recommendation V.36 is similar to RS- 449 where certain signals are RS-422 signals and others are RS-423. Depending on different ap- plications; "Transmit Data", "Terminal Timing", "Request-to-Send", "Data Terminal Ready", "Receive Data", "Transmit Clock", "Receive Clock", "Clear-to-Send", "Data Carrier Detect", and "DataSet Ready" are specified as Category 1 Circuits where the protocol is RS-422 for rates over 20kbps. All other circuits are Category 2 Circuits which are specified as RS-423 circuits. Depending on particular signals, the SP503 can be easily used for V.36. When the two drivers, ST and TT, are in tri-state mode, what will the driver outputs tolerate for maximum short circuit voltages? And the re- ceiver, SCT, input? The driver outputs will tolerate up to ±16.0V without any damage to the circuit regardless of whether or not ST and TT are in tri-state mode. The tri-state circuitry does not affect the short circuit protection on the driver outputs. The SCT receiver input will tolerate up to ±16.0V without any damage to the input structure regardless of whether or not SCT is in tri-state mode. What does Sipex recommend for transient volt- age suppression techniques for the SP503 ? For our evaluation boards, Sipex uses transient voltage suppressor ICs from ProTek Devices, model numbers LCA05C to LCA15C. The two digits in the part number pertain to the rated stand-off voltage, V WM , which is the maximum working DC voltage applied to the device. These TVS devices are especially designed for serial data communications because of their low ca- pacitance and low impedance. However, please be aware that V WM values below the specified input range of the transceiver will affect the input impedance. For example, it would be fine to use a 5V V WM value for RS-422 but for RS-232, the receiver input voltage range is ±15V where lower V WM voltages will drive the impedance to ground. Another recommended manufacturer is AVX Corporation TransGuard series of TVS compo- nents. AVX offers a variety of surface mount back-to-back diodes. ProTek Devices • P.O. Box 3129 • Tempe, AZ. 85280

• 602-431-8101 AVX Corporation • Myrtle Beach, SC • 803-448-9411 The drawing on page 232 shows the SP503 configured with the ProTek SM16LC15C TVS devices to protect the drivers and receivers from ESD and over-voltage. Will the SP503 conform to the physical layer testing specified by NET1/NET2 for X.21 and X.25 systems? Sipex initiated a component level test for NET1/ SP503 passed all the physical layer testing re- quirements prescribed by NET1/NET2. A full test report can be furnished upon request.

Creating extra RS-232 channels using the SP310A 22µF2 2 µF 22µF 25 27 26 30 28 31 32 1N5819 VCC VDD C1- C2-V SSC1+ C2+ 22µF 1459 +5V SP503CF Drivers TxD 58 20 2356DTR 54 4 1952RTS 63 24 1165TxC 44ST 47 21 45RL 51 18 49LL 70 3 1671RxD 1 37 17 938RxC 20 66 5 1367CTS 80 68 6 69DSR 78 35 8 1036DCD 19 39 22 40RI 21 76 15 1277SCT Receivers +5V SP310ACT RDEC 1 RDEC 1 DB-25 connector in DTE configuration. VCC VDD C1- C2-V SSC1+ C2+ VCC C1- C2-C1+ C2+ ON/OFF V- 32 4 5 6 TM 10 9 0.1µF 0.1µF0.1µF0.1µF(Pin 3 of the SP503)

Creating extra differential channels using the SP485 22µF2 2 µF 22µF 25 27 26 30 28 31 32 1N5819 VCC VDD C1- C2-V SSC1+ C2+ 22µF 1459 +5V SP503CF Drivers TxD 58 20 2356DTR 54 4 1952RTS 63 24 1165TxC 44ST 47 21 45RL 51 18 49LL 70 3 1671RxD 1 37 17 938RxC 20 66 5 1367CTS 80 68 6 69DSR 78 35 8 1036DCD 19 39 22 40RI 21 76 15 1277SCT Receivers +5V VCC 1µF SP485 TDEC 2 TDEC 2 DB-25 connector in DTE configuration. RDEC 1 (pin 3 of the SP503) DI DE RO RE B A

Using Transient Voltage Suppressors with the SP503 22µF 25 27 26 30 1N5819 VCC VDD C1-C2- VSS C1+C2+ 22µF SP503CF Drivers TxD DTR RTS TxC ST RL LL RxD RxC CTS DSR DCD RI SCT Receivers * - Please note that the ProTek transient voltage suppressors should also be con- nected to the other SP503 drivers and re- ceivers in the same configuration as shown above. 28 31 22µF +5V 15 14 13 12 11 10 23 45 67 ProTek Devices SM16LC15C 15 14 13 12 11 10 23 45 67 ProTek Devices SM16LC15C

ORDERING INFORMATION

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