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Designing with the SP505, SP506, & SP507 Multi-Protocol Serial Transceivers
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.
SP505/6/7APN/03
SP505, SP506, SP507 Application Note
(c) Copyright 2000 Sipex Corporation
1
DTE Configuration to a DB-25 Serial Port
The SP505, SP506 and SP507 can easily be configured as a DTE in all serial communication applications. The SP505, SP506 and SP507 contain seven drivers and seven receivers to support most of the signals required for proper serial communications. Figure 1 summarizes the usual signals used in synchronous serial communications. The basic configuration shown in Figure 2 illustrates a connection to a DB-25 D-sub connector commonly used for EIA-530 and RS-232. For other serial interface protocols, the decoder can be used to select the physical layer interface. The DEC0-3 of the SP505 and SP506 will program its internal drivers and receivers to electrically adhere to
the appropriate interface. The SP507 decoder is slightly different and uses 3-bits to select the desired interface. For the appropriate physical connection, a "daughter" cable can be attached to the DB-25 connector (female pins on cable) and transfer the signals to the physically compliant connector. For example, a V.35 interface will have a ISO-2593 34-pin connector. For a V.35 DTE interface, the SP505, SP506 and SP507 can be programed to V.35 mode and a daughter cable, having a DB-25 female connector on one end and a V.35 34-pin male connector on the other end, will allow the equipment to have an electrically and physically complaint V.35 interface.
EIA-232
Signal Name
Shield Transmitted Data Received Data Request To Send Clear To Send DCE Ready (DSR) DTE Ready (DTR) Signal Ground Recv. Line Sig. Det. (DCD) Trans. Sig. Elemt. Timing Recv. Sig. Elemt. Timing Local Loopback Remote Loopback Ring Indicator Trans. Sig. Elemt. Timing Test Mode -- DTE DCE DTE DCE DCE DTE -- DCE DCE DCE DTE DTE DCE DTE DCE -- BA BB CA CB CC CD AB CF DB DD LL RL CE DA TM 1 2 3 4 5 6 20 7 8 15 17 18 21 22 24 25
EIA-530
-- BA (A) BA (B) BB (A) BB (B) CA (A) CA (B) CB (A) CB (B) CC (A) CC (B) CD (A) CD (B) AB CF (A) CF (B) DB (A) DB (B) DD (A) DD (B) LL RL -- DA (A) DA (B) TM 1 2 14 3 16 4 19 5 13 6 22 20 23 7 8 10 15 12 17 9 18 21 -- 24 11 25
EIA-449
-- SD (A) SD (B) RD (A) RD (B) RS (A) RS (B) CS (A) CS (B) DM (A) DM (B) TR (A) TR (B) SG RR (A) RR (B) ST (A) ST (B) RT (A) RT (B) LL RL -- TT (A) TT (B) TM 1 4 22 6 24 7 25 9 27 11 29 12 30 19 13 31 5 23 8 26 10 14 -- 17 35 18
V.35
-- 103 103 104 104 105 106 107 108 102 109 114 114 115 115 141 140 125 113 113 142 A P S R T C D E H* B F Y AA V X L* N* J* U* W* NN *
X.21
Mnemonic Pin
-- Circuit T(A) Circuit T(B) Circuit R(A) Circuit R(B) Circuit C(A) Circuit C(B) Circuit I(A) Circuit I(B) 1 2 9 4 11 3 10 5 12
Source Mnemonic Pin Mnemonic Pin Mnemonic Pin Mnemonic Pin
Circuit G
8
Circuit B(A)** Circuit B(B)** Circuit S(A) Circuit S(B)
7 14 6 13
Circuit X(A)** Circuit X(B)**
7 14
* - Optional signals ** - Only one of the two X.21 signals, Circuit B or X, can be implemented and active at one time.
1 9
8 15
1 14
7 20
13 25
X.21 Connector (ISO 4903)
DTE Connector -- DB-15 Pin Male DCE Connector -- DB-15 Pin Female
RS-232 & EIA-530 Connector (ISO 2110)
DTE Connector -- DB-25 Pin Male DCE Connector -- DB-25 Pin Female
NN JJ DD Z
V T
R N
L J K
F D E C
B
1 20
5 25
10 30
15 33
19 37
LL FF BB X MM HH CC Y
UP
A
RS-449 Connector (ISO 4902)
DTE Connector Face -- DB-37 Pin Male DCE Connector Face - DB-37 Pin Female
KK EE AA W
SMH
V.35/ISO 2593 Connector
DTE Connector Face -- 34 Pin Male DCE Connector Face -- 34 Pin Female
Figure 1. Signals and Connector Allocation Table
SP505/6/7APN/03
SP505, SP506, SP507 Application Note
(c) Copyright 2000 Sipex Corporation
2
1N5819, MBRS140T3, or equiv.
10F 10F
+5V
10F
10F
Various VCC pins (Refer to SP506 Datasheet) Drivers
TxD 14 DTR 13 RTS 16 TxC 15 ST 22
27 26
VCC VDD
30
28
31
32 61 59 58 56 54 52 63 65 42 44 47 45 51 49 70 71 37 38 66 67 68 69 35 36 39 40 76 77
10F
C1+
C1V C2+ C2- SS
DB-25 Connector Pins & Signals
2 14 20 23 4 19 24 11 n/a n/a 21 n/a 18 3 16 17 9 5 13 6 22 8 10 25 15 12
2 3 4 18 5 23 12
#103 #108 #105 #113
TXD(a) TXD(b) DTR(a) DTR(b) RTS(a) RTS(b) TXCE(a) TXCE(b)
#140 #141 Receivers #104 #115 #106 #107 #109 #142 #114
RL 17 LL 24 RxD 1 RxC 20 CTS 80 DSR 78 DCD 19 RI 21 SCT 79 SDEN
RL LL RXD(a) RXD(b) RXC(a) RXC(b) CTS(a) CTS(b) DSR(a) DSR(b) DCD(a) DCD(b) TM TXC(a) TXC(b)
M0 M1 (V.28_Enable) M2 (V.11_Enable) M3
12 11 10 9
DEC0 DEC1 DEC2 DEC3
TREN RSEN RLEN LLEN STEN TTEN
SP506CF
Mode_Enable
8 LATCH
SCTEN GND
7
+5V
Various GND pins (Refer to SP506 Datasheet)
Mode Selection
M3 M2 M1 M0 0 0 0 0 0 1 0 0 0 0 1 0 1 1 0 0 1 1 0 1 1 1 1 0 1 1 1 1
Mode Enable
Physical Layer SHUTDOWN X.21 (V.11) RS-232 (V.28) RS-449 (V.11 & V.10) EIA-530 (V.11 & V.10) V.35 (V.35 & V.28) EIA-530A (V.11 & V.10)
7
SIGNAL GND
Figure 2. SP506 DTE Configuration
SP505/6/7APN/03
SP505, SP506, SP507 Application Note
(c) Copyright 2000 Sipex Corporation
3
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.
SP505/6/7APN/03
SP505, SP506, SP507 Application Note
(c) Copyright 2000 Sipex Corporation
4
1N5819, MBRS140T3, or equiv.
10F 10F
+5V
10F
10F
Various VCC pins (Refer to SP506 Datasheet) Drivers
TxD 14 DTR 13 RTS 16 TxC 15 ST 22 RL 17 LL 24 RxD 1 RxC 20 CTS 80 DSR 78 DCD 19 RI 21 SCT 79
27 26
VCC VDD
30
28
31
32 61 59 58 56 54 52 63 65 42 44 47 45 51 49 70 71 37 38 66 67 68 69 35 36 39 40 76 77
10F
C1+
C1V C2+ C2- SS
DB-25 Connector Pins & Signals
3 16 6 22 5 13 17 9 15 12 8 10 25 2 14 24 11 4 19 20 23 21 18 n/a n/a
2 3 4 18 5 23 12
#104 #107 #106 #115 #114 #109 #142 Receivers #103 #113 #105 #108 #140 #141
RXD(a) RXD(b) DSR(a) DSR(b) CTS(a) CTS(b) RXC(a) RXC(b) TXC(a) TXC(b) DCD(a) DCD(b) TM TXD(a) TXD(b) TXCE(a) TXCE(b) RTS(a) RTS(b) DTR(a) DTR(b) RL LL
SDEN
M0 M1 (V.28_Enable) M2 (V.11_Enable) M3
12 11 10 9
DEC0 DEC1 DEC2 DEC3
TREN RSEN RLEN LLEN STEN TTEN
SP506CF
Mode_Enable
8 LATCH
SCTEN GND
7
Various GND pins (Refer to SP506 Datasheet)
Mode Selection
M3 M2 M1 M0 0 0 0 0 0 1 0 0 0 0 1 0 1 1 0 0 1 1 0 1 1 1 1 0 1 1 1 1
Mode Enable
Physical Layer SHUTDOWN X.21 (V.11) RS-232 (V.28) RS-449 (V.11 & V.10) EIA-530 (V.11 & V.10) V.35 (V.35 & V.28) EIA-530A (V.11 & V.10)
7
SIGNAL GND (#102)
Figure 3. SP506 DCE Configuration
SP505/6/7APN/03
SP505, SP506, SP507 Application Note
(c) Copyright 2000 Sipex Corporation
5
1N5819, MBRS140T3, or equiv.
10F 10F
+5V
10F
10F
Various VCC pins (Refer to SP506 Datasheet) Drivers
TxD 14 DTR 13 RTS 16 TxC 15 ST 22 RL 17 LL 24 RxD 1 RxC 20 CTS 80 DSR 78 DCD 19 RI 21 SCT 79
27 26
VCC VDD
30
28
31
32 61 59 58 56 54 52 63 65 42 44 47 45 51 49 70 71 37 38 66 67 68 69 35 36 39 40 76 77
10F
C1+
C1V C2+ C2- SS
DB-25 Connector Pins & Signals [DTE/DCE]
2 14 20 23 4 19 24 11 15 12 21 18 3 16 17 9 5 13 6 22 8 10 25 TXD(a)/RXD(a) TXD(a)/RXD(b) DTR(a)/DSR(a) DTR(b)/DSR(b) RTS(a)/CTS(b) RTS(b)/CTS(b) TXCE(a)/TXC(a) TXCE(b)/TXC(b) *TXC(a)/RXC(a) *TXC(b)/RXC(b) RL/DCD(a)** LL/TM RXD(a)/TXD(a) RXD(b)/TXD(b) RXC(a)/TXCE(a) RXC(b)/TXCE(b) CTS(a)/RTS(a) CTS(b)/RTS(b) DSR(a)/DTR(a) DSR(b)/DTR(b) DCD(a)/RL or DCD(a)** DCD(b)/DCD(b) TM/LL
#103_DTE/#104_DCE #108_DTE/#107_DCE #105_DTE/#106_DCE #113_DTE/#115_DCE #114_DTE/#114_DCE #140_DTE/#109_DCE #141_DTE/#142_DCE Receivers #104_DTE/#103_DCE #115_DTE/#113_DCE #106_DTE/#105_DCE #107_DTE/#108_DCE #109_DTE/#140_DCE** #142_DTE/#141_DCE
SDEN
2 3 4 18 5 23 12 7
M0 M1 (V.28_Enable) M2 (V.11_Enable) M3
12 11 10 9
DEC0 DEC1 DEC2 DEC3
TREN RSEN RLEN LLEN STEN TTEN
SP506CF
Mode_Enable
8 LATCH
SCTEN GND
DCE/DTE Control
Mode Selection
M3 0 0 0 1 1 1 1
Mode M2 M1 M0 Enable Physical Layer 0 0 0 SHUTDOWN 1 0 0 X.21 (V.11) 0 1 0 RS-232 (V.28) 1 0 0 RS-449 (V.11 & V.10) 1 0 1 EIA-530 (V.11 & V.10) 1 1 0 V.35 (V.35 & V.28) 1 1 1 EIA-530A (V.11 & V.10)
Various GND pins (Refer to SP506 Datasheet)
7
SIGNAL GND (#102)
* - Driver applies for DCE only on pins 24 and 11. Receiver applies for DTE only on pins 24 and 11. ** - RL may not be required in some applications and DCD may be required to be bi-directional. If RL is not required The RL is replaced by DCD(a) and the #140_DCE is replaced by #109_DCE. The RL driver of the SP505 will not be in use during DCE mode in this case.
Input Line Output Line 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.
Figure 4. SP506 DTE/DCE Programmable Configuration
SP505/6/7APN/03
SP505, SP506, SP507 Application Note
(c) Copyright 2000 Sipex Corporation
6
1N5819, MBRS140T3, or equiv.
10F 10F
DB-25 Connector Pins & Signals [DTE/DCE]
31 32 61 59 58 56 54 52 63 65 42 44 47 45 51 49 70 71 37 38 66 67 68 69 35 36 39 40 76 77 10F
+5V
10F
10F
Various VCC pins (Refer to SP507 Datasheet) Drivers
TxD 14 DTR 13 RTS 16 TxC 15 DCE_ST 22 RL 17 LL 24 RxD 1 RxC 20 CTS 80 DSR 78 DCD 19 TM 21 DTE_ST 79
27 26
VCC VDD
30
28
C1+
C1V C2+ C2- SS
#103_DTE/#104_DCE #108_DTE/#107_DCE #105_DTE/#106_DCE #113_DTE/#115_DCE #114_DTE/#114_DCE #109_DTE/#109_DCE #141_DTE/#141_DCE Receivers #104_DTE/#103_DCE #115_DTE/#113_DCE #106_DTE/#105_DCE #107_DTE/#108_DCE
2 14 20 23 4 19 24 11
TXD(a)/RXD(a) TXD(a)/RXD(b) DTR(a)/DSR(a) DTR(b)/DSR(b) RTS(a)/CTS(b) RTS(b)/CTS(b) TXCE(a)/TXC(a) TXCE(b)/TXC(b)
18 3 16 17 9 5 13 6 22 8 10 15 12 7
*LL/TM RXD(a)/TXD(a) RXD(b)/TXD(b) RXC(a)/TXCE(a) RXC(b)/TXCE(b) CTS(a)/RTS(a) CTS(b)/RTS(b) DSR(a)/DTR(a) DSR(b)/DTR(b) *DCD(a)/DCD(a) *DCD(b)/DCD(b) *TXC(a)/RXC(a) *TXC(b)/RXC(b) SIGNAL GND 1 SHIELD GND
RTEN
2 3 4 7 5 18 6 23
M0 M1 M2
12 11 10
M0 M1 M2 TERM_OFF
RREN TMEN SCTEN LLEN RLEN TTEN STEN GND
SP507CF
Mode Selection
M2 M1 0 0 0 0 0 1 0 1 1 0 1 0 1 1 1 1 M0 0 1 0 1 0 1 0 1
Mode Enable
+5V
8
LATCH
Physical Layer V.11 (RS-422) EIA-530A EIA-530 X.21 V.35 RS-449 (V.36) RS-232 SHUTDOWN
Various GND pins (Refer to SP507 Datasheet)
+5V
DCE/DTE Control
* - 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. Receiver applies for DCE mode only on pin 18 for signal LL. Driver applies for DTE mode only on pin 18.
Input Line Output Line I/O Lines represented by double arrowhead signifies a bi-directional bus.
Figure 5. SP507 DTE/DCE Programmable Configuration (Similar configuration to competitor's 3-chip solution.)
SP505/6/7APN/03
SP505, SP506, SP507 Application Note
(c) Copyright 2000 Sipex Corporation
7
1N5819, MBRS140T3, or equiv.
10F 10F 10F 10F 27 26 30 28 31 32 Various VCC pins (Refer to SP506 Datasheet) VCC VDD C1VSS C1+ C2+ C2-
Semtech SLVG2.8
+5V
10F
to HDLC DTE/DCE
Transzorbs can be added to the digital I/Os for daughter board configurations where the interface card may be hot inserted into another board. Semtech's SLVG2.8 or similar will protect against ESD or over-voltage transients during hot insertion. The rated clamping range is from -0.6V to +5.3V.
Connector Pins
[DB-25 EIA-530, ISO-2593 V.35]
DTE/DCE Symbol
#103/#104
59 58 56 54 52 63 65 42 44 47 45 51 49 70 71 37 38 66 67 68 69 35 36 39 40 76 77 SDEN 9 10 11 12 DEC0 LLEN STEN TTEN 8 SCTEN GND
Various GND pins (Refer to SP506 Datasheet)
SLVG2.8
Drivers
TxD 14 DTR 13 RTS 16 TxC 15
61
SLVG2.8
SLVG2.8
SLVG2.8
SLVG2.8
SP505/6/7APN/03
2, P 14, S 20, H 23 4, C 19 24, U 11, W
N/C N/C N/C
RL 17 ST 22
#108/#107
SLVG2.8
#105/#106
SLVG2.8
#113/#115
SLVG2.8
TXD(a)/RXD(a) TXD(b)/RXD(b) DTR(a)/DSR(a) DTR(b)/DSR(b) RTS(a)/CTS(a) RTS(b)/CTS(b) TXCE(a)/RXC(a) TXCE(b)/RXC(b)
#140
N/C
SLVG2.8
21, N 18, L
N/C
RL(a)/RL(a) LL/TM
#141/#142
SLVG2.8
Receivers
RxD 1 RxC 20 CTS 80 DSR 78 DCD 19 RI 21
LL 24
#104/#103
SLVG2.8
#115/#113
SLVG2.8
#106/#105
SLVG2.8
#107/#108
SLVG2.8
#109
N/C
SLVG2.8
#142/#141
SCT 79 2 3 4 18 5 23 12 7 1 2 3 6 7 8
N/C N/C
SLVG2.8
3, R 16, T 17, V 9, X 5, D 13 6, E 22 8, F 10 25, NN 15, Y 12, AA
N/C
RXD(a)/TXD(a) RXD(b)/TXD(b) RXC(a)TXCE(a) RXC(b)/TXCE(b) CTS(a)/RTS(a) CTS(b)/RTS(b) DSR(a)/DTR(a) DSR(b)/DTR(b) DCD(a)/DCD(a) DCD(b)/DCD(b) TM/LL TXC(a)/TXC(a) TXC(b)/TXC(b)
#114
TREN RSEN RLEN
SLVG2.8
DEC3 DEC2 DEC1
SP506
LATCH
1
2
3
6
7
8
1
2
3
4
5
6
7
1
2
3
4
5
6
7
+5V
4
5
4
5
8
8
Semtech LCDA15C-6
Semtech LCDA15C-6
Semtech SMDA15C-7
Semtech SMDA15C-7
+5V
SP506 for DTE
1N5819, MBRS140T3, or equiv.
Transzorbs are optional for added protection against ESD and over-voltage transients. Recommended are Semtech's LCDA15C-6 on the clock and data lines (low capacitance for high speed signals) and SMDA15C-7 on the control/handshaking lines.
Figure 6. Complete DTE/DCE Programmable Serial Port w/o Crossover Cables
SP505, SP506, SP507 Application Note
+5V
10F 10F 27 26 30 28 31 32 Various VCC pins (Refer to SP506 Datasheet) VCC VDD C1VSS C1+ C2+ C210F 10F 10F
8
Drivers
TxD 14 59 58 56 54 52 63 65 42 44 47 45 51 49 70 71 37 38 66 67 68 69 35 36 39 40 76 SCT 79 SDEN
SLVG2.8 SLVG2.8 SLVG2.8 SLVG2.8
61
DTR 13 RTS 16 TxC 15 ST 22 RL 17 LL 24 RxD 1 RxC 20 CTS 80 DSR 78 DCD 19 RI 21
Receivers
N/C
N/C
M7 M6 M5 M4
N/C
77 2 9 10 11 12 DEC3 DEC2 DEC1 DEC0 TREN RSEN RLEN LLEN 3 4 18 5
N/C N/C N/C
Control Logic from FPGA or PLD
Mode
D_E
M7
M6
M5
M4
M3
M2
M1
M0
M3 M2 M1 M0
SP506
8 LATCH
STEN TTEN SCTEN GND
Various GND pins (Refer to SP506 Datasheet)
23 12 7
RS-232 EIA-530 RS-449 V.35 X.21 V.36
DTE DTE DTE DTE DTE DTE
0 1 1 1 0 0
0 1 1 1 1 1
1 0 0 1 0 1
0 1 0 0 0 0
0 0 0 0 0 0
0 0 0 0 0 0
0 0 0 0 0 0
0 0 0 0 0 0
+5V
RS-232 EIA-530 RS-449 V.35 X.21 V.36
DCE DCE DCE DCE DCE DCE
0 0 0 0 0 0
0 0 0 0 0 0
0 0 0 0 0 0
0 0 0 0 0 0
0 1 1 1 0 0
0 1 1 1 1 1
1 0 0 1 0 1
0 1 0 0 0 0
+5V
(c) Copyright 2000 Sipex Corporation
SP506 for DCE
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 100A of leakage current. Even with the maximum SP506 leakage current of 500A, the receiver input impedance would only change by 500. 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 5k. For V.11 differential receivers, the maximum range is +7V and typical input impedance is 10k. Thus for V.28 receivers, the drivers would be effectively driving into 5k in parallel with the disabled receiver with 10k input impedance. The resultant impedance is 3.3k. For V.11 mode, the drivers will drive into either a terminated receiver of 120 or unterminated receiver at 3.9k. These two values in parallel with the disabled 10k receiver will yield 118 and 2.8k, respectively, and will not degrade the V.11 driver performance. The receiver outputs are typically at 1A 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.
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 VCC 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 VDD back into VCC through the capacitor, ensuring that a rapidly rising VDD does not rise too quickly above the VCC 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 PowermiteTM 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.
Adding Additional Transceivers
To support additional signals, the SP522 can easily attach onto the SP505, SP506 or SP507 charge pump outputs, VDD 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.
PowermiteTMis a trademark of Motorola.
SP505/6/7APN/03 SP505, SP506, SP507 Application Note (c) Copyright 2000 Sipex Corporation
9
+5V
DB-25 Connector Pins & Signals [DTE/DCE]
10F
VDD
VCC T1OUT
#141_DTE/#125_DCE
T1IN ENT1 ENR1
18 25
LL/TM TM/LL
#125_DTE/#141_DCE
1N5819, MBRS140T3, or equiv.
R1IN LBK
R1OUT
+5V
22F 22F
DP0 DP1 VSS
SP522
GND
22F
+5V
10F
Various VCC pins (Refer to SP507 Datasheet) Drivers
TxD 14 DTR 13 RTS 16 TxC 15 DCE_ST 22 RL 17 LL 24 RxD 1 RxC 20 CTS 80 DSR 78 DCD 19 TM 21 DTE_ST 79
27 26
VCC VDD
30
28
31 61 59 58 56 54 52 63 65 42 44 47 45 51 49 70 71 37 38 66 67 68 69 35 36 39 40 76 77 RTEN 2 3 4 7 5 18 6 23
22F
C1+
C1V C2+ C2- SS 32
#103_DTE/#104_DCE #108_DTE/#107_DCE #105_DTE/#106_DCE #113_DTE/#115_DCE #114_DTE/#114_DCE #109_DTE/#109_DCE #140_DTE/#140_DCE Receivers #104_DTE/#103_DCE #115_DTE/#113_DCE #106_DTE/#105_DCE #107_DTE/#108_DCE
2 14 20 23 4 19 24 11
TXD(a)/RXD(a) TXD(a)/RXD(b) DTR(a)/DSR(a) DTR(b)/DSR(b) RTS(a)/CTS(b) RTS(b)/CTS(b) TXCE(a)/TXC(a) TXCE(b)/TXC(b)
21 3 16 17 9 5 13 6 22 8 10 15 12 7
*RL/RL RXD(a)/TXD(a) RXD(b)/TXD(b) RXC(a)/TXCE(a) RXC(b)/TXCE(b) CTS(a)/RTS(a) CTS(b)/RTS(b) DSR(a)/DTR(a) DSR(b)/DTR(b) *DCD(a)/DCD(a) *DCD(b)/DCD(b) *TXC(a)/RXC(a) *TXC(b)/RXC(b) SIGNAL GND 1 SHIELD GND
M0 M1 M2
12 11 10
M0 M1 M2 TERM_OFF
RREN TMEN SCTEN LLEN RLEN TTEN
SP507CF
Mode Selection
M2 M1 0 0 0 0 0 1 0 1 1 0 1 0 1 1 1 1 M0 0 1 0 1 0 1 0 1
Mode Enable
+5V
8
LATCH STEN GND
Physical Layer V.11 (RS-422) EIA-530A EIA-530 X.21 V.35 RS-449 (V.36) RS-232 SHUTDOWN
Various GND pins (Refer to SP507 Datasheet)
+5V
* - 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. Receiver applies for DCE mode only on pin 18 for signal LL. Driver applies for DTE mode only on pin 18.
DCE/DTE Control
Input Line Output Line I/O Lines represented by double arrowhead signifies a bi-directional bus.
Figure 7. Adding the SP522 to the SP507 in a DTE/DCE Programmable Configuration
SP505/6/7APN/03
SP505, SP506, SP507 Application Note
(c) Copyright 2000 Sipex Corporation
10
SP506 and SP507 Drive Capability
According to the ITU-T V.11 standard, the maximum cable length for a differential V.11 transmission is 4,000 feet (~1,000 meters). However, the standard also illustrates a derating graph of data rate versus cable length. So actually in a real application, the system would not be able to transmit 10Mbps over the full 4,000 feet of Category 3 or similar type cable. As cable parasitics add up over longer cable lengths, capacitance and other affects will degrade the signal, especially at higher frequencies. The signal integrity depends mainly on the driver output strength or "drivability" and parasitic capacitance on the cable. RS-232 cabling is typically 50pF per foot, where as a good twisted pair type cable for X.21, RS-449, EIA-530, or V.35 will typically be 10pF per foot or less. Some better quality cables will have 3-5pF per foot.
Using a typical setup with a TTC Fireberd 6000A Bit Error Rate Tester (BERT) connected with our SP507 evaluation board as configured in Figure 8 below, the driver output performance was characterized over various cable lengths. The 6000A BERT emulated the DCE, which provided the TXC clock pulse from 1.544Mbps to 12Mbps. The clock waveform was propagated through the serial cable to the SP507 evaluation board, which was configured as the DTE. The clock signal was then "echoed" through the TxCE (Transmit Clock Echo) driver across the cable and back the BERT. The clock signal input to the TxCE driver (CH3) and the differential driver output are measured with a oscilloscope to observe driver waveform integrity. The differential driver output was measured at the other end of the cable (M1 = A - B), as if the receiver would view the incoming signal. The data stream was generated by the DCE and was propagated through the SP507's RxC receiver and TxCE driver. The BERT also records the number of bit errors occurring during the infinite 1:1 data bit stream that is sent back through the cable.
DTE (Evaluation Board)
MBRS140T3
22F 22F 22F 10F
VCC
+5V
DCE (emulated)
31 32 61 22F 59 58 56 54 52 63 65 42 44 47 45 51 49 70 71 37 38 66 67 68 69 35 36 39 40 76 77
27 26
VDD
30
28
C1+
C1V C2+ C2- SS
TxD 14
RxD DSR CTS RxC M1
CH3
DTR 13 RTS 16 TxCE 15 ST 22 RL 17 LL 24 RxD 1 RxC 20 CTS 80 DSR 78 DCD 19 TM 21 SCT 79 RTEN 12 11 10
6ft. to
Fireberd 6000A Network/BER Tester
TxD TxC RTS DTR DCD TxC
2 3 4 7 5 18 6 23
"0" "0" "1"
M0 M1 M2
RREN TMEN SCTEN LLEN
Cable
Length
used:
156ft.
Signal GND
SP507CF
8 LATCH GND
RLEN TTEN STEN
+5V
Various GND pins (Refer to SP507 Datasheet)
+5V
Notes: V.35 Mode selected. Open Driver Inputs are default as HIGH.
Figure 8. SP507 Cable Length Versus Throughput Circuit Configuration
SP505/6/7APN/03
SP505, SP506, SP507 Application Note
(c) Copyright 2000 Sipex Corporation
11
Figure 9. SP507 TxCE at 2.048MHz over 6ft.
Figure 10. SP507 TxCE at 2.048MHz over 56ft.
Figure 11. SP507 TxCE at 2.048MHz over 106ft.
Figure 12. SP507 TxCE at 2.048MHz over 156ft.
Figure 13. SP507 TxCE at 6.312MHz over 6ft.
Figure 14. SP507 TxCE at 6.312MHz over 56ft.
SP505/6/7APN/03
SP505, SP506, SP507 Application Note
(c) Copyright 2000 Sipex Corporation
12
Figure 15. SP507 TxCE at 6.312MHz over 106ft.
Figure 16. SP507 TxCE at 6.312MHz over 156ft.
Figure 17. SP507 TxCE at 8.192MHz over 6ft.
Figure 18. SP507 TxCE at 8.192MHz over 56ft.
Figure 19. SP507 TxCE at 8.192MHz over 106ft.
Figure 20. SP507 TxCE at 8.192MHz over 156ft.
SP505/6/7APN/03
SP505, SP506, SP507 Application Note
(c) Copyright 2000 Sipex Corporation
13
Figure 21. SP507 TxCE at 10MHz over 6ft.
Figure 22. SP507 TxCE at 10MHz over 56ft.
Figure 23. SP507 TxCE at 10MHz over 106ft.
Figure 24. SP507 TxCE at 10MHz over 156ft.
Figure 25. SP507 TxCE at 12MHz over 6ft.
Figure 26. SP507 TxCE at 12MHz over 56ft.
SP505/6/7APN/03
SP505, SP506, SP507 Application Note
(c) Copyright 2000 Sipex Corporation
14
12MHz signaling was still readable by the DCE. This is because the V.35 receiver input sensitivity is 200mV maximum. As the signal amplitude decays to approximately 400mVP (832mVP-P), there is still enough gain on the signal for the receiver to successfully read the clock. Although the AC performance across the system is worse as the receiver input sensitivity is higher. The V.35 specification does not take into account any capacitive loading for the Terminated Transmitter Output measurement. Therefore it would be unfair to use the V.35 specification as a criteria for pass/fail in a real application environment. Signal monotonicity and duty cycle are the important, measurable elements to determining a clean and error-free clock transmission. Note that these oscilloscope photos are a typical representation of the SP507's performance in presence of cabling using our in-house evaluation board. The system designer should test and characterize the system in order determine the cable distance versus speed allowance in the application.
Figure 27. SP507 TxCE at 12MHz over 86ft.
The V.35 interface was selected because the V.35 signal has low voltage differential amplitude, which is more susceptible to noise compared to other higher amplitude signals such as V.11 or RS-485. The small amplitude of 0.55V can easily be affected by noise caused by various environmental effects. SP506 and SP507 driver performance was characterized over 6ft., 26ft., 56ft., 86ft, 106ft., 126ft., and 156ft. V.35 cable lengths. The frequency measured are from 1.544MHz, 2.048MHz, 3.152MHz, 6.312MHz, 8.192MHz, 9.600MHz, 10MHz, and 12MHz. The scope photos and graphs on Figures 9 through 27 illustrate the some of these measurements. The Fireberd 6000A was able to synchronize with the incoming TxCE clock signal and read the TxD output data stream up to a 12MHz clock without any bit errors. This implies that the clock source had sufficient amplitude and was stable enough for the DCE receiver to read back and synchronize the data on the clock's rising edge. The transmission was successful up to 12MHz with 86 feet of V.35 cable without bit errors. Further cable length degraded the signal to a point where the receiver was unable to capture the clock, thus not able to synchronize data and resulting in bit errors. One important note is that the signal no longer adheres to the V.35 specification for Transmitter Differential Output with Termination (per CCITT V.35 Section II.3.c) of 0.44V minimum after 56 feet at 10MHz. However, longer cable lengths and even
SP505/6/7APN/03
SP505, SP506, SP507 Application Note
(c) Copyright 2000 Sipex Corporation
15
ESD Protection and EMI Filtering
It is now a requirement for networking equipment, in order to receive the European "CE" mark, to withstand a certain amount of environmental hazards. Among these are ESD and EMI immunity as well as EMI emissions, which is the equipment's own generation of electromagnetic interference. Electrostatic discharge and overvoltage transients are important to suppress in any system. The specification generally used for ESD immunity is EN61000-4-2 (formerly IEC1000-4-2), which specifies Air Discharge and Contact Discharge Methods. For "CE" approval, the acceptance level is generally "Level 2" per the IEC1000-4-2 specification, which is 4kV Air Discharge and 4kV Contact Discharge. While the SP505, SP506, and SP507 has reasonable handling withstand voltages built in the I/O structures of the device, external protection is always a good idea. One method of protection is incorporating TransZorbsTM or transient voltage suppression ICs, which are back-to-back Zener diodes connected on the line to ground. There are a variety of manufacturers such as Motorola, Siemens, Semtech, Protek Devices, and more. The key specifications are:
1) Reverse Standoff Voltage - normal circuit operating voltage. For RS-232, the maximum VRWM = 15V. 2) Peak Pulse or Transient Current - expected transient current. (IPP) 3) Reverse Breakdown Voltage - device begins to avalanche and becomes a low impedance path to ground for the transient. (VBR) 4) Maximum Junction Capacitance - loading capacitance of the diode structure. More capacitance will affect the total AC performance. (CJ)
Lower VRWM values can be selected instead of 15V. If the configuration is straightforward, using 5V to 8V VRWM values is fine for the driver outputs and receiver inputs. Using 5V VRWM on the driver is fine since the clamping occurs at the reverse breakdown voltage(VBR), which is 6V for most 5V transzorbs. However, during compliancy testing, the V.28 receiver may be subjected to 15V in order to test the input impedance. Applying a voltage exceeding the VRWM rating will affect the input current measurement and thus fail the impedance test.
I
Ipp
Vbr Vc
Vrwm
It Ir Ir It
V
Vrwm Vbr Vc
Ipp
Figure 28. I-V Curve of a TVS diode
A variety of transzorbs were tested and all perform well in the presence of ESD transients. For faster data rates such as V.11 and V.35 signals, low capacitance is important since an additional 50pF load could add 5ns to the transition time and affect the overall transmission rate. The Semtech LCDA15C-6 and Protek Devices SM16LC15C are especially designed for data communications because of the multichannel line support and the low junction capacitance.
Figure 29 illustrates a TVS configuration using the Semtech LCDA15C-6 connected to the clock and data signals of the SP505, SP506 and SP507. The LCDAC-6 was chosen due to its low junction capacitance of 20pF, which are important for high speed clock and data lines. Protek's SM16LC15C can also be used as the junction capacitance is 25pF. However, the two TVS devices are not pin compatible. Protek's SM16LC15C contains protection for eight lines and has a straight-through pinout. One side of the SM16LC15C is grounded. The LCDAC-6 uses a 8-pin SOIC package as opposed to the 16-pin package with the SM16LC15C. Since two ICs are needed anyway for clock and data, the smaller package is usually preferred. Refer to each of the manufacturer's datasheet for details. Figure 30 illustrates a TVS configuration to the handshaking signals. As these signals are for control and indication, they do not usually switch at high speed. The junction capacitance for these devices are less critical.
TransZorb is a trademark of General Semiconductor Industries.
SP505/6/7APN/03 SP505, SP506, SP507 Application Note (c) Copyright 2000 Sipex Corporation
16
TxD(a) TxD(b) TxCE(a) TxCE(b) TxCE(a) TxCE(b) RxD(a) RxD(b) RxC(a) RxC(b)
1
2
3
6
7
8
1
2
3
6
7
8
Signal GND
4
5
4 Semtech LCDA15C-6
5
Semtech LCDA15C-6
Figure 29. TVS Configuration to Clock and Data Lines of the SP505/SP506/SP507
RTS(a) RTS(b) DTR(a) DTR(b) DCD(a) DCD(b) LL
CTS(a) CTS(b) DSR(a) DSR(b)
TM
1
2
3
4
5
6
7
1
2
3
4
5
Signal GND
Semtech SMDA15C-7
8
8
Semtech SMDA15C-5
Figure 30. TVS Configuration to Handshaking Signal Lines of the SP505/SP506/SP507
SP505/6/7APN/03
SP505, SP506, SP507 Application Note
(c) Copyright 2000 Sipex Corporation
17
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 TransZorbsTM 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
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 VDD 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, VDD 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 22F 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)
SP505/6/7APN/03
SP505, SP506, SP507 Application Note
(c) Copyright 2000 Sipex Corporation
18
Another alternative is using conductive-EMI enhanced connectors that have ferrite cores around the pins. AMP and other connector manufacturers also offer specially built conductive-EMI filtered connectors. The AMPLIMITETM Subminiature D-Sub connectors have a DB-15 through DB-37 connectors as well as high density connectors that have a distributed element filter using lossy ferrite core or a capacitive filter assembled around each pin. These connectors have right-angle, vertical, or stacked versions that all have the same PCB footprint as the regular non-filtered connectors. Various filter types are available with these connectors. Once the serial protocol is defined and the operating frequency known, a filter type can be chosen using its 3dB point, which can be used as the maximum frequency. The filter will begin filtering above this 3dB point. One should be careful when using the capacitive filters as they will affect the overall AC performance of the driver, specifically driver rise/ fall time. Details of the AMPLIMITETM filtered connectors can be found in AMP's home page (http://connect.amp.com.), which includes insertion loss (dB) versus frequency.
8
1 2
L1 L2 L3 L4
TxD
7
6
3 4
TXCE
5
Figure 31. Common-Mode Choke Circuit with Drivers
AMPLIMITETM is a trademark of AMP Inc.
SP505/6/7APN/03
SP505, SP506, SP507 Application Note
(c) Copyright 2000 Sipex Corporation
19
Using Smaller Charge Pump Capacitors with the SP50x
The charge pump of the SP505, SP506, and SP507 have been designed to drive the RS-232 voltage levels through the drivers using 22F pump capacitors. However, the SP505, SP506, and SP507 can use 10F capacitors for operation while still maintaining the critical specifications. There are two issues involved with lowering the charge pump capacitors; RS-232 driver output VOH and VOL levels, and output ripple. Figure 32 shows the typical driver output (TxD in this case) in an unloaded condition using 10F charge pump capacitors. Figure 33 shows the same driver
but loaded with 3k and 2,500pF to ground. Running at a worse case speed of 120kHz, the driver output voltages shown in Figure 34 clearly comply with the RS-232 and ITU-T V.28 specifications under these conditions. Figures 34 and 35 show the driver output's ripple when a DC input is asserted. The ripple in Figure 34 uses 22F charge pump capacitors where as Figure 35 uses 10F capacitors. The ripple amplitude is increased from approximately 60mV to 400mV. Although the RS-232 voltages are within the specifications and the ripple amplitude is negligible compared to the RS-232 signal amplitude, the designer should examine the EMC consequences of reducing the charge pump capacitors.
Figure 32. Unloaded Driver Output Using 10F Pump Capacitors
Figure 33. Driver Output Loaded w/ 3k // 2,500pF Using 10F Pump Capacitors
Figure 34. Charge Pump Ripple of Driver Output w/ 22F Pump Capacitors
SP505/6/7APN/03
Figure 35. Charge Pump Ripple of Driver Output w/ 10F Pump Capacitors
(c) Copyright 2000 Sipex Corporation
SP505, SP506, SP507 Application Note
20
SP506 and SP507 Evaluation Boards
For easy bench testing of the SP506 and SP507, evaluation boards are available. Similar to the SP505EB, the SP506EB and SP507EB offers a "breakout" type configuration that allows the user to access the driver's and receiver's I/Os. The evaluation boards have a DB-25 serial connector that is configured to a EIA-530 DTE pinout. This connector can be used to analyze any of the serial standards offered in the SP506 and SP507. Translation cables may be needed from the DB-25 to the appropriate connector. Refer to Figure 1 or the cabling schemes in the Design Guide for Multi-Protocol Serial Ports. Refer to the SP504/SP505 Evaluation Board Manual for the SP506EB. For the SP507EB, the probe pins or access points are arranged such that the drivers are on one side and the receivers are on the other. Each driver has three basic access points: the TTL input, inverting analog output, and non-inverting analog output. Additional
access points are included for the driver outputs, thus a total of four access points for each driver. Similarly with the receiver with two analog inputs, inverting and non-inverting, and the TTL output. Receiver inputs have additional access points for convenience. There are additional ground points for convenient resistor or capacitor load connections to the driver output access points. There are also receiver ground points for convenience at each receiver. The TTL control lines have DIP switches that allow the user to input a signal to enter a logic HIGH or logic LOW. The control lines include the driver and receiver enable lines and the mode select pins. For the SP506EB, the driver enable inputs are active LOW and have internal pull down resistors. The DIP switch position will either tie the inputs to a logic HIGH or leave the input open where the internal pull-down defines a LOW state. For the SP507EB, the SP507 uses a logic HIGH for its driver enable lines except for the LL driver, which
D1 C3 VCC 10F
25 33 41 48 55 62 73 74
VCC VCC
C1 C2
30 28 31 32 61
DB-25 Connector Pins & Signals [DTE] C4
2 14 20 23 4 19 24 11 ST(a) ST(b) 21 RL(b) 18 LL(b) 3 16 17 9 5 13 6 22 8 10 25 TM(b) 15 12
GND located next to each driver output & receiver input
27 26
VDD
C1V C1+ C2+ C2- SS
TxD DTR RTS TxC DCE_ST RL Mode Selection
M2 M1 0 0 0 0 0 1 0 1 1 0 1 0 1 1 1 1 M0 0 1 0 1 0 1 0 1
Mode Enable
14 13 16 15 22 17 24 1 20 80 78 19 21 79 2 3 4 7 5 18 6 23
59 58 56 54 52 63 65 42 44 47 45 51 49 70 71 37 38 66 67 68 69 35 36 39
SD(a) SD(a) TR(a) TR(b) RS(a) RS(b) TT(a) TT(b) RL(a) LL(a) RD(a) RD(a) RT(a) RT(b) CS(a) CS(b) DM(a) DM(b) RR(a) RR(b) TM(a) SCT(a) SCT(b) SIGNAL GND 1 SHIELD GND
Physical Layer V.11 (RS-422) EIA-530A EIA-530 X.21 V.35 RS-449 (V.36) RS-232 SHUTDOWN
LL RxD RxC CTS DSR DCD
OFF
VCC
TM DTE_ST
40 76 77
7
RTEN RREN TMEN SCTEN LLEN RLEN TTEN STEN
SP507CF
GND GND GND GND GND GND GND GND GND GND GND 29 34 43 46 50 53 57 60 64 72 75
FUSE, jumper or 50ohm 1/4W resistor
ON
VCC
OFF
TERM_OFF
LATCH
M2 10
M1 11
M0 12
D1 = MBRS140T3 Schottky Rectifier C1 ~ C4 = 22F Kemet T491C226K016AS Decoupling Capacitor = 10F Kemet T351C106K10AS301
ON
Reference Design Schematic
TERM_OFF LATCH M2 M1 M0
Orig.: Zeferino Cervantes Chkd.: John Ng 233 South Hillview Dr. * Milpitas, CA. 95035 Appr.: Kim Y. Lee Customer : Title : Date :
Sipex Corporation SP507 Evaluation Board
Original : June 9, 1999
Doc. # :
TEST308
Rev.
A
Figure 36. SP507EB Schematic
SP505/6/7APN/03
SP505, SP506, SP507 Application Note
(c) Copyright 2000 Sipex Corporation
21
has a logic LOW enable. The receivers use a logic LOW enable for its receiver enable lines except for the TM receiver, which has a logic HIGH enable. The DIP switches for the SP507EB evaluation board is such that the "down" position of the switch will be considered "ON" and the "up" position will be considered "OFF", regardless up enable polarity. Note that the SP507EB Rev. A boards will have the label on the switches reversed. But the true state is all transceivers enabled when rocker switches are positioned down. On the right side of the board with the driver inputs, there is a common bus named INPUT, which has access points next to each driver input. This bus is added on the board for convenience so that the driver inputs can all be connected together via jumper wires to this bus. The INPUT trace can be followed on the top layer of the board. The other DIP switch will configure the physical layer protocol desired on the transceiver IC. The SP507 uses three bits M0, M1, and M2. The decoder bits will be logic HIGH when the toggle position is "down" The /TERM_OFF will be logic LOW when in the rocker "down" position. The /LATCH pin will be logic HIGH in the rocker "down" position. The "FUSE" connection on the board is included to connect the shield ground to the signal ground. A 1- to 100 resistor can be placed into the FUSE position. EIA-530, EIA-530A, and RS-449 standards state that a 100, 1/4W resistor should isolate the shield or earth ground from the signal ground on the DTE side. Loopbacks and other testing can be easily performed by the use of jumper wires or cables. All necessary points on the boards are labelled. The SP507 Evaluation Board (Rev. A) schematic is shown on Figure 36. The SP507EB (Rev A.) layout plot is shown on Figure 38.
SP505, 506 and SP507 Retrofits
Along with our SP506 Evaluation (SP506EB) and SP507 Evaluation Boards (SP507EB), Sipex also offers SP506 or SP507 Retrofit Boards (SP506RB and SP507RB). Shown in Figure 37, these retrofit boards are design to map onto existing motherboards and replace an existing serial port platform. These boards are approximately 1.375" x 1.375" and contain the four charge pump capacitors and one Schottky diode needed for compliant operation. The boards also have the connections for driver inputs and outputs and receiver inputs and outputs. Using a ribbon type cable or "flex-board", the analog I/Os can be mapped to the appropriate pin assignment on the serial port connector and the TLL/CMOS I/Os to the HDLC serial controller IC. The equipment's existing serial transceiver ICs can be depopulated and replaced by the retrofit board. Sipex usually prefers to perform the retrofitting in-house. But the experienced designer can also retrofit the serial port as well. Once connected properly, the functionality and electrical performance will be transparent to the user. Sipex will perform the necessary testing to ensure the retrofit is electrically transparent and complaint to the physical layer specifications. Sipex has already passed homologation testing per NET1/2 and TBR2 with this board retrofitted onto a router.
Figure 37. SP507 Retrofit Board
SP505/6/7APN/03
SP505, SP506, SP507 Application Note
(c) Copyright 2000 Sipex Corporation
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Figure 38. SP507 Evaluation Board Layout
SP505/6/7APN/03
SP505, SP506, SP507 Application Note
(c) Copyright 2000 Sipex Corporation
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More Compliancy.... In order for networking equipment to be connected in the European network or even offered in Europe, it must be thoroughly tested to a set of specifications. Serial ports are no exception to the rule and are tested to ensure compliancy to their respective ITU specifications. This is to ensure proper operation to the public network as the equipment is connected. This is a requirement in order to obtain the "CE" mark for European compliance. In January of 1998, CTR1/CTR2 compliancy could officially be attained by using another test option called TBR2. The Technical Basis for Regulation specification was recently finalized and approved for use as a test criteria for certification. Similar to NET1/2, the testing ensures that the serial port adheres to the ITU-T V-Recommendations. It specifies the connector type and the signals required between the DTE and DCE. However, there are some minor testing differences. Paragraph 6.3.1 - V.10 Interface 6.3.1.1 Generator open circuit output voltage The single-ended generator or driver's output (point A), for either binary state, shall be less than or equal to 12.0V when terminated with a 3.9k resistor to ground (point C).
A
450
Vt
C
Figure 40. V.10 Driver Terminated Voltage
6.3.1.3 Generator output rise/fall time The driver output's transition from one binary point to another shall be less than or equal to 0.3 of the nominal bit duration (tb). This is measured between 10% and 90% of its steady state value and with a 450 resistor load to ground. 6.3.1.4 Generator polarities The driver's single-ended output A shall be: a) greater than point C (VOUT > 0V) when the signal condition 0 is transmitted for data circuits, or ON for control circuits; and b) less than point C (VOUT < 0V) when the signal condition 1 is transmitted for data circuits, or OFF for control circuits.
A
A
3.9k
VOC
450
Oscilloscope
C
C
Figure 39. V.10 Driver Open Circuit Voltage
Figure 41. V.10 Driver Transition Time
6.3.1.2 Generator terminated output voltage The driver output's magnitude, for either binary state, shall be greater than or equal to 2.0V when terminated with a 450 resistor to ground.
SP505/6/7APN/03
SP505, SP506, SP507 Application Note
(c) Copyright 2000 Sipex Corporation
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Paragraph 6.3.2 - V.11 Circuits 6.3.2.1 Generator open circuit output voltage The magnitude of the driver's outputs for: a) between point A and point B b) either point A or point B to point C shall be less than or equal to 12.0V for either binary state when terminated with a 3.9k resistor between points A and points B.
6.3.2.3 Generator output rise/fall time The driver outputs' transition from one binary point to another shall be less than or equal to 0.3 of the nominal bit duration (tb). This is measured between 10% and 90% of its steady state value and with a "Y" resistor configuration. The resistor network contains two 50 resistors in series with a center-tap 50 resistor between the two series resistors to ground. 6.3.2.4 Generator polarities The driver's point A output shall be: a) greater than point B (VA-VB > 0V) when the signal condition 0 is transmitted for data circuits, or ON for control circuits; and b) less than point B (VA-VB < 0V) when the signal condition 1 is transmitted for data circuits, or OFF for control circuits.
A
VOCA
3.9k
VOC
V
OCB
B
C
A
50
Figure 42. V.11 Driver Open Circuit Voltage
Oscilloscope
50
6.3.2.2 Generator terminated output voltage The magnitude of the driver's outputs for: a) between point A and point B b) either point A or point B to point C shall be greater than or equal to 2.0V for either binary state when terminated with two 50 resistors connected in series between point A and point B. The center point of the two 50 resistors shall measure less than or equal to 3.0V with respect to point C.
B
50
C
Figure 44. V.11 Transition Time
A
Paragraph 6.3.3 - V.28 Circuits 6.3.3.1 Generator open circuit output voltage The single-ended generator or driver's output (point A), for either binary state, shall be less than or equal to 25.0V with respect to ground (point C). 6.3.1.2 Generator terminated output voltage The driver output's magnitude, for either binary state, shall be greater than or equal to 3.0V when terminated with a 3k resistor to ground.
50 VT 50
B
VOS
C
Figure 43. V.11 Driver Output Terminated Voltage
SP505/6/7APN/03
6.3.1.3 Generator output rise/fall time The driver output's transition from one binary point to another shall be less than or equal to 3% or 1.0ms, whichever is greater, of the nominal bit duration (tb). This is measured between +3V and -3V of the transition and with 3k resistor // 2500pF loads to ground.
(c) Copyright 2000 Sipex Corporation
SP505, SP506, SP507 Application Note
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A
VOC
6.3.1.4 Generator polarities The driver's single-ended output A shall be: a) greater than point C (VOUT > 0V) when the signal condition 0 is transmitted for data circuits, or ON for control circuits; and b) less than point C (VOUT < 0V) when the signal condition 1 is transmitted for data circuits, or OFF for control circuits. 6.3.3.5 Receiver maximum shunt capacitance The total effective shunt capacitance shall be less than 2500pF at point A with respect to ground. This is measured by applying a 14VP signal with 0V offset at 9.6kbps with 50% duty cycle through a 1.2k resistor. The rise time measured from -3V to +3V at point A to point C (t1) and the fall time measured from +3V to -3V at point A to point C (t2) is measured and recorded. Then replace the receiver with a 3k resistor in parallel with a 2500pF capacitor and apply the same signal through the 1.2k resistor. The new rise time (t3) is recorded and compared to t1 and t2. The times t1 and t2 shall be less than or equal to t3.
C
Figure 45. V.28 Driver Open Circuit Voltage
A
3k
VT
C
Figure 46. V.28 Driver Terminated Voltage
A
1.2k
9600bps, 14.0Vp-p Square Wave
VL
A
C
3k
2500pF
Oscilloscope
C
Figure 48. V.28 Receiver Effective Shunt Capacitance
Figure 47. V.28 Transition Time
SP505/6/7APN/03
SP505, SP506, SP507 Application Note
(c) Copyright 2000 Sipex Corporation
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Paragraph 6.3.4 - V.35 Circuits 6.3.4.1 Generator open circuit output voltage The magnitude of the driver's outputs for: a) between point A and point B b) either point A or point B to point C shall be less than or equal to 1.2V for either binary state when terminated with a 3.9k resistor between points A and points B.
6.3.4.3 Generator output rise/fall time The driver outputs' transition from one binary point to another shall be less than or equal to 0.1 of the nominal bit duration (tb). This is measured between 20% and 80% of its steady state value and with a "Y" resistor configuration. The resistor network contains two 50 resistors in series with a center-tap 50 resistor between the two series resistors to ground. 6.3.4.4 Generator polarities The driver's point A output shall be: a) greater than point B (VA-VB 0V) when the signal condition 0 is transmitted for data circuits, or ON for control circuits; and b) less than point B (VA-VB 0V) when the signal condition 1 is transmitted for data circuits, or OFF for control circuits.
A
V
OCA
3.9k
VOC
VOCB
B
C
A
Figure 49. V.35 Driver Open Circuit Voltage
50
Oscilloscope
6.3.4.2 Generator terminated output voltage The magnitude of the driver's outputs for: a) between point A and point B b) either point A or point B to point C shall be 0.55V +20% for either binary state when terminated with two 50 resistors connected in series between point A and point B. The center point of the two 50 resistors shall measure less than or equal to 0.6V with respect to point C.
50 B 50
C
Figure 51. V.35 Transition Time
A
50 VT 50 VOS
B
The SP505 has been successfully tested to CTR1/ CTR2 through TUV Telecom Services. The test was performed on the SP505EB Evaluation Board. The test report CTR2/052101/98 can be furnished upon request. The SP507 has also successfully passed the CTR1/CTR2 testing requirements through KTL using our SP507EB. The test report 9D2566DEU1 can also be furnished upon request. Please contact Sipex Applications for details.
C
Figure 50. V.35 Driver Terminated Voltage
SP505/6/7APN/03 SP505, SP506, SP507 Application Note (c) Copyright 2000 Sipex Corporation
27
Figure 52. Front Cover of the CTR1/CTR2 Test Report for the SP505
SP505/6/7APN/03
SP505, SP506, SP507 Application Note
(c) Copyright 2000 Sipex Corporation
28
Figure 53. Front Cover of the CTR1/CTR2 Test Report for the SP507
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SP505, SP506, SP507 Application Note
(c) Copyright 2000 Sipex Corporation
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ORDERING INFORMATION
Multi-Protocol Transceiver Products
Model Temperature Range Package Types SP505CF ........................................................................... 0C to +70C ......................................................... 80-pin JEDEC (BE-2 Outline) QFP SP506CF ........................................................................... 0C to +70C ......................................................... 80-pin JEDEC (BE-2 Outline) QFP SP507CF ........................................................................... 0C to +70C ......................................................... 80-pin JEDEC (BE-2 Outline) QFP
Evaluation and Retrofit Boards
Model Description SP505EB ........................................................................................................................................................................ SP505CF Evaluation Board SP506EB ........................................................................................................................................................................ SP506CF Evaluation Board SP507EB ........................................................................................................................................................................ SP507CF Evaluation Board SP505RB ............................................................................................................................................................................. SP505CF Retrofit Board SP506RB ............................................................................................................................................................................. SP506CF Retrofit Board SP507RB ............................................................................................................................................................................. SP507CF Retrofit Board
Evaluation Kits
(Boxed with SP5xxEB, Product Datasheet, Application Note)
Model Description SP505EK .............................................................................................................................................................................. SP505CF Evaluation Kit SP506EK .............................................................................................................................................................................. SP506CF Evaluation Kit SP507EK .............................................................................................................................................................................. SP507CF Evaluation Kit
Corporation
SIGNAL PROCESSING EXCELLENCE
Sipex Corporation Headquarters and Sales Office 22 Linnell Circle Billerica, MA 01821 TEL: (978) 667-8700 FAX: (978) 670-9001 e-mail: sales@sipex.com Sales Office 233 South Hillview Drive Milpitas, CA 95035 TEL: (408) 934-7500 FAX: (408) 935-7600
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.
SP505/6/7APN/03
SP505, SP506, SP507 Application Note
(c) Copyright 2000 Sipex Corporation
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