View LTC1545_336504.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

Final Electrical Specifications
LTC1545 Software-Selectable Multiprotocol Transceiver
December 1998
FEATURES
s s
DESCRIPTION
The LTC(R)1545 is a 5-driver/5-receiver multiprotocol transceiver. The LTC1545 and LTC1543 form the core of a complete software-selectable DTE or DCE interface port that supports the RS232, RS449, EIA530, EIA530-A, V.35, V.36 or X.21 protocols. Cable termination may be implemented using the LTC1344A software-selectable cable termination chip or by using existing discrete designs. The LTC1545 runs from a 5V supply and the charge pump on the LTC1543. The part is available in a 36-lead SSOP surface mount package.
s s
s s
Software-Selectable Transceiver Supports: RS232, RS449, EIA530, EIA530-A, V.35, V.36, X.21 TUV/Detecon Inc. Certified NET1 and NET2 Compliant (Test Report No. NET2/071601/98) TBR2 Compliant (Test Report No. CTR2/071601/98) Software-Selectable Cable Termination Using the LTC1344A Complete DTE or DCE Port with LTC1543, LTC1344A Operates from Single 5V Supply with LTC1543
APPLICATIONS
s s s
Data Networking CSU and DSU Data Routers
, LTC and LT are registered trademarks of Linear Technology Corporation.
TYPICAL APPLICATION
DTE or DCE Multiprotocol Serial Interface with DB-25 Connector
RL TM RI LL CTS DSR DCD DTR RTS RXD RXC TXC SCTE TXD
LTC1545 D5 R5 R4 D4 D3 R3 R2 R1 D2 D1 R3 R2 R1
LTC1543 D3 D2 D1
21
RL A (140)
25
TM A (142)
*
RI A (125)
18 13 5
CTS A (106) CTS B LL A (141)
10 8
DSR B DSR A (109)
22 6
DCD B DCD A (107)
23 20 19 4
DTR B DTR A (108) RTS B RTS A (105) SHIELD (101)
1
SG (102)
7
16 3
RXD B RXD A (104)
9
RXC B
17
RXC A (115)
12 15 11 24 14
SCTE B SCTE A (113) TXD B TXD A (103) TXC B TXC A (114)
DB-25 CONNECTOR
Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
U
U
U
LTC1344A
2 *OPTIONAL
1545 TA01
1
LTC1545
ABSOLUTE MAXIMUM RATINGS
(Note 1)
PACKAGE/ORDER INFORMATION
TOP VIEW VCC VDD D1 D2 D3 R1 R2 R3 D4 1 2 3 4 5 6 7 8 9 R1 R2 R3 D4 R4 R5 D5 G PACKAGE 36-LEAD PLASTIC SSOP D3 D1 D2 36 VEE 35 GND 34 D1 A 33 D1 B 32 D2 A 31 D2 B 30 D3/R1 A 29 D3/R1 B 28 R2 A 27 R2 B 26 R3 A 25 R3 B 24 D4 A 23 R4 A 22 R5 A 21 D5 A 20 VDD 19 VCC
Supply Voltage, VCC ................................................ 6.5V Input Voltage Transmitters ........................... - 0.3V to (VCC + 0.3V) Receivers ............................................... - 18V to 18V Logic Pins .............................. - 0.3V to (VCC + 0.3V) Output Voltage Transmitters .................. (VEE - 0.3V) to (VDD + 0.3V) Receivers ................................ - 0.3V to (VCC + 0.3V) Logic Pins .............................. - 0.3V to (VCC + 0.3V) VEE ........................................................ - 10V to 0.3V VDD ....................................................... - 0.3V to 10V Short-Circuit Duration Transmitter Output ..................................... Indefinite Receiver Output .......................................... Indefinite VEE .................................................................. 30 sec Operating Temperature Range ..................... 0C to 70C Storage Temperature Range ................ - 65C to 150C Lead Temperature (Soldering, 10 sec)................. 300C
ORDER PART NUMBER LTC1545CG
R4 10 M0 11 M1 12 M2 13 DCE/DTE 14 D4ENB 15 R4EN 16 R5 17 D5 18
TJMAX = 150C, JA = 65C/ W
Consult factory for Industrial and Military grade parts.
ELECTRICAL CHARACTERISTICS
SYMBOL Supplies ICC VCC Supply Current (DCE Mode, All Digital Pins = GND or VCC) PARAMETER
VCC = 5V, VDD = 8V, VEE = - 7V for V.28, - 5.5V for V.10, V.11 (Notes 2, 3)
MIN
q q q q q q q q q q q q q q q q
CONDITIONS RS530, RS530-A, X.21 Modes, No Load RS530, RS530-A, X.21 Modes, Full Load V.28 Mode, No Load V.28 Mode, Full Load No-Cable Mode, D4ENB = HIGH RS530, RS530-A, X.21 Modes, No Load RS530, X.21 Modes, Full Load RS530-A, Full Load V.28 Mode, No Load V.28 Mode, Full Load No-Cable Mode, D4ENB = HIGH RS530, RS530-A, X.21 Modes, NoLoad RS530, RS530-A, X.21 Modes, Full Load V.28 Mode, No Load V.28 Mode, Full Load No-Cable Mode, D4ENB = HIGH RS530, RS530-A, X.21 Modes, Full Load V.28 Mode, Full Load
TYP 2.7 110 1 1 10 2.0 23 34 1 12 10 0.3 0.3 1 13.5 10 340 64
MAX 5 150 3 3 500 4.0 35 50 3 18 500 2 2 3 18 500
UNITS mA mA mA mA A mA mA mA mA mA A mA mA mA mA A mW mW
IEE
VEE Supply Current (DCE Mode, All Digital Pins = GND or VCC)
IDD
VDD Supply Current (DCE Mode, All Digital Pins = GND or VCC)
PD
Internal Power Dissipation (DCE Mode, (All Digital Pins = GND or VCC)
2
U
W
U
U
WW
W
LTC1545
ELECTRICAL CHARACTERISTICS
SYMBOL VIH VIL IIN PARAMETER Logic Input High Voltage Logic Input Low Voltage Logic Input Current D1, D2, D3, D4, D5 M0, M1, M2, DCE, D4ENB, R4EN = GND M0, M1, M2, DCE, D4ENB, R4EN = VCC IO = - 4mA IO = 4mA 0V VO VCC M0 = M1 = M2 = VCC, 0V VO VCC RL = 1.95k (Figure 1) RL = 50 (Figure 1) RL = 50 (Figure 1) RL = 50 (Figure 1) RL = 50 (Figure 1) RL = 50 (Figure 1) VOUT = GND - 0.25V VO 0.25V, Power Off or No-Cable Mode or Driver Disabled (Figures 2, 5) (Figures 2, 5) (Figures 2, 5) (Figures 2, 5) (Figures 2, 5) - 7V VCM 7V - 7V VCM 7V - 10V VA,B 10V - 10V VA,B 10V (Figures 2, 6) (Figures 2, 6) (Figures 2, 6) (Figures 2, 6)
q q q q q q q q q q q q q q q q q
VCC = 5V, VDD = 8V, VEE = - 7V for V.28, - 5.5V for V.10, V.11 (Notes 2, 3)
MIN
q q q q q q q q
CONDITIONS
TYP
MAX
UNITS V
Logic Inputs and Outputs 2 0.8 - 100 3 - 50 - 50 4.5 0.3 40 1 5 0.5VODO 2 0.67VODO V 0.2 3 0.2 150 1 2 20 20 0 15 40 40 3 3 - 0.2 15 15 30 15 50 50 0 4 80 80 16 0.2 40 0.66 100 25 65 65 12 V V V mA A ns ns ns ns ns V mV mA k ns ns ns ns 0.8 50 10 - 30 10 V A A A V V mA A V
VOH VOL IOSR IOZR V.11 Driver VODO VODL VOD VOC VOC ISS IOZ t r, t f t PLH t PHL t t SKEW VTH VTH IIN RIN t r, t f t PLH t PHL t
Output High Voltage Output Low Voltage Output Short-Circuit Current Three-State Output Current Open Circuit Differential Output Voltage Loaded Differential Output Voltage Change in Magnitude of Differential Output Voltage Common Mode Output Voltage Change in Magnitude of Common Mode Output Voltage Short-Circuit Current Output Leakage Current Rise or Fall Time Input to Output Input to Output Input to Output Difference, tPLH - tPHL Output to Output Skew Input Threshold Voltage Input Hysteresis Input Current (A, B) Input Impedance Rise or Fall Time Input to Output Input to Output Input to Output Difference, tPLH - tPHL
V.11 Receiver
3
LTC1545
ELECTRICAL CHARACTERISTICS
SYMBOL V.10 Driver VO VT ISS IOZ t r, t f t PLH t PHL VTH VTH IIN RIN t r , tf tPLH tPHL t V.28 Driver VO ISS IOZ SR t PLH t PHL VTHL VTLH VTH RIN t r , tf tPLH tPHL Output Voltage Short-Circuit Current Output Leakage Current Slew Rate Input to Output Input to Output Input Low Threshold Voltage Input High Threshold Voltage Receiver Input Hysterisis Receiver Input Impedance Rise or Fall Time Input to Output Input to Output - 15V VA 15V (Figures 4, 8) (Figures 4, 8) (Figures 4, 8)
q q
VCC = 5V, VDD = 8V, VEE = - 7V for V.28, - 5.5 for V.10, V.11 (Notes 2, 3)
MIN
q q
PARAMETER Output Voltage Output Voltage Short-Circuit Current Output Leakage Current Rise or Fall Time Input to Output Input to Output Receiver Input Threshold Voltage Receiver Input Hysteresis Receiver Input Current Receiver Input Impedance Rise or Fall Time Input to Output Input to Output Input to Output Difference, tPLH - tPHL
CONDITIONS Open Circuit, RL = 3.9k RL = 450 (Figure 3) RL = 450 (Figure 3) VO = GND - 0.25V VO 0.25V, Power Off or No-Cable Mode or Driver Disabled RL = 450. CL = 100pF (Figures 3, 7) RL = 450. CL = 100pF (Figures 3, 7) RL = 450. CL = 100pF (Figures 3, 7)
q q q
TYP
MAX 6
UNITS V V
4 3.6 0.9VO
150 0.1 2 1 1 - 0.25 25 15 30 15 55 109 60
q q q q q q q
mA A s s s
100
V.10 Receiver 0.25 50 0.66 V mV mA k ns ns ns ns 10 150 1 4 1.3 1.3 1.5 2 3 1.6 0.1 5 15 60 150 100 450 0.3 7 100 30 2.5 2.5 0.8 V V mA A V/s s s V V V k ns ns ns
- 10V VA 10V - 10V VA 10V (Figures 4, 8) (Figures 4, 8) (Figures 4, 8) (Figures 4, 8) Open Circuit RL = 3k (Figure 3) VO = GND - 0.25V VO 0.25V, Power Off or No-Cable Mode or Driver Disabled RL = 3k, CL = 2500pF (Figures 3, 7) RL = 3k, CL = 2500pF (Figures 3, 7) RL = 3k, CL = 2500pF (Figures 3, 7)
q q
5
8.5
V.28 Receiver
q q q q
The q denotes specifications which apply over the full operating temperature range. Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired.
Note 2: All currents into device pins are positive; all currents out of device are negative. All voltages are referenced to device ground unless otherwise specified. Note 3: All typicals are given for VCC = 5V, VDD = 8V, VEE = - 7V for V.28, - 5.5V for V.10, V.11 and TA = 25C.
4
LTC1545
PIN FUNCTIONS
VCC (Pins 1, 19): Positive Supply for the Transceivers. 4.75V VCC 5.25V. Connect a 1F capacitor to ground. VDD (Pins 2, 20): Positive Supply Voltage for V.28. Connect to VDD Pin 3 on LTC1543 or 8V supply. Connect a 1F capacitor to ground. D1 (Pin 3): TTL Level Driver 1 Input. D2 (Pin 4): TTL Level Driver 2 Input. D3 (Pin 5): TTL Level Driver 3 Input. R1 (Pin 6): CMOS Level Receiver 1 Output. R2 (Pin 7): CMOS Level Receiver 2 Output. R3 (Pin 8): CMOS Level Receiver 3 Output. D4 (Pin 9): TTL Level Driver 4 Input. R4 (Pin 10): CMOS Level Receiver 4 Output. M0 (Pin 11): TTL Level Mode Select Input 0 with Pull-Up to VCC. M1 (Pin 12): TTL Level Mode Select Input 1 with Pull-Up to VCC. M2 (Pin 13): TTL Level Mode Select Input 2 with Pull-Up to VCC. DCE/DTE (Pin 14): TTL Level Mode Select Input with Pull-Up to VCC. Logic high enables Driver 3. Logic low enables Receiver 1. D4ENB (Pin 15): TTL Level Enable Input with Pull-Up to VCC. Logic low enables Driver 4. R4EN (Pin 16): TTL Level Enable Input with Pull-Up to VCC. Logic high enables Receiver 4. R5 (Pin 17): CMOS Level Receiver 5 Output. D5 (Pin 18): TTL Level Driver 5 Input. D5 A (Pin 21): Driver 5 Output. R5 A (Pin 22): Receiver 5 Input. R4 A (Pin 23): Receiver 4 Input. D4 A (Pin 24): Driver 4 Input. R3 B (Pin 25): Receiver 3 Noninverting Input. R3 A (Pin 26): Receiver 3 Inverting Input. R2 B (Pin 27): Receiver 2 Noninverting Input. R2 A (Pin 28): Receiver 2 Inverting Input. D3/R1 B (Pin 29): Receiver 1 Noninverting Input and Driver 3 Noninverting Output. D3/R1 A (Pin 30): Receiver 1 Inverting Input and Driver 3 Inverting Output. D2 B (Pin 31): Driver 2 Noninverting Output. D2 A (Pin 32): Driver 2 Inverting Output. D1 B (Pin 33): Driver 1 Noninverting Output. D1 A (Pin 34): Driver 1 Inverting Output. GND (Pin 35): Ground. VEE (Pin 36): Negative Supply Voltage. Connect to VEE Pin 26 on LTC1543. Connect a 1F capacitor to ground.
TEST CIRCUITS
A RL VOD RL B VOC
1545 F02
1545 F01
Figure 1. V.11 Driver Test Circuit
U
U
U
B A
RL 100
CL 100pF CL 100pF
B A
R
15pF
Figure 2. V.11 Driver/Receiver AC Test Circuit
5
LTC1545
TEST CIRCUITS
D A CL RL
D
A
A
R 15pF
1545 F04
1545 F03
Figure 3. V.10/V.28 Driver Test Circuit
Figure 4. V.10/V.28 Receiver Test Circuit
ODE SELECTIO
M2 0 0 0 0 1 1 1 1
LTC1545 MODE NAME Not Used (Default V.11) RS530A RS530 X.21 V.35 RS449/V.36 V.28/RS232 D4ENB = 1, R4EN = 0 M0 = M1 = M2 = 1
Note 1: Driver 3 and Receiver 1 are enabled (and disabled) by DCE/DTE (Pin 14). Logic high enables Driver 3. Logic low enables Receiver 1.
SWITCHI G TI E WAVEFOR S
5V D 0V VO B-A -VO A VO B t SKEW t SKEW
1545 F05
1.5V t PLH 50% tr 90% 10%
f = 1MHz : t r 10ns : t f 10ns
1/2 VO
Figure 5. V.11 Driver Propagation Delays
6
W
U
M1 0 0 1 1 0 0 1 1 M0 0 1 0 1 0 1 0 1 D1 V.11 V.11 V.11 V.11 V.28 V.11 V.28 Z D2 V.11 V.10 V.11 V.11 V.28 V.11 V.28 Z (Note 1) (Note 2) D3 D4 V.11 V.11 V.11 V.11 V.28 V.11 V.28 Z V.10 V.10 V.10 V.10 V.28 V.10 V.28 Z D5 V.10 V.10 V.10 V.10 V.28 V.10 V.28 Z (Note 1) R1 V.11 V.11 V.11 V.11 V.28 V.11 V.28 Z R2 V.11 V.10 V.11 V.11 V.28 V.11 V.28 Z R3 V.11 V.11 V.11 V.11 V.28 V.11 V.28 Z (Note 3) R4 V.10 V.10 V.10 V.10 V.28 V.10 V.28 Z R5 V.10 V.10 V.10 V.10 V.28 V.10 V.28 Z Note 2: Driver 4 is enabled by D4ENB = 0 (Pin 15). Note 3: Receiver 4 is enabled by R4EN = 1 (Pin 16).
1.5V t PHL VDIFF = V(B) - V(A) 90% tf 50% 10%
W
U
W
LTC1545
SWITCHI G TI E WAVEFOR S
VOD2 B-A -VOD2 VOH R VOL 0V t PLH 1.5V OUTPUT f = 1MHz : t r 10ns : t f 10ns INPUT 0V t PHL 1.5V
1545 F06
Figure 6. V.11 Receiver Propagation Delays
3V D 0V VO A -VO tf 1.5V t PHL 3V 0V -3V -3V tr 0V 1.5V t PLH 3V
1545 F07
Figure 7. V.10, V.28 Driver Propagation Delays
VIH A VIL VOH R VOL 1.5V t PHL 1.5V 1.5V t PLH 1.5V
1545 F08
Figure 8. V.10, V.28 Receiver Propagation Delays
APPLICATIONS INFORMATION
Overview The LTC1543/LTC1545 form the core of a complete software-selectable DTE or DCE interface port that supports the RS232, RS449, EIA530, EIA530-A, V.35, V.36 or X.21 protocols. Cable termination may be implemented using the LTC1344A software-selectable cable termination chip or by using existing discrete designs. A complete DCE-to-DTE interface operating in EIA530 mode is shown in Figure 9. The LTC1543 of each port is used to generate the clock and data signals. The LTC1545 is used to generate the control signals along with LL (Local Loop-back), RL (Remote Loop-Back), TM (Test Mode) and RI (Ring Indicate). The LTC1344A cable termination chip is used only for the clock and data signals because they must support V.35 cable termination. The control signals do not need any external resistors. Mode Selection The interface protocol is selected using the mode select pins M0, M1 and M2 (see the Mode Selection table). For example, if the port is configured as a V.35 interface, the mode selection pins should be M2 = 1, M1 = 0, M0 = 0. For the control signals, the drivers and receivers will operate in V.28 (RS232) electrical mode. For the clock and data signals, the drivers and receivers will operate in V.35 electrical mode. The DCE/DTE pin will configure the port for DCE mode when high, and DTE when low. The interface protocol may be selected simply by plugging the appropriate interface cable into the connector. The mode pins are routed to the connector and are left unconnected (1) or wired to ground (0) in the cable as shown in Figure 10.
W
U
W
U
W
U
U
7
LTC1545
APPLICATIONS INFORMATION
DTE
SERIAL CONTROLLER TXD LTC1543 D1 LTC1344A TXD LTC1344A 103
SCTE
D2
D3
TXC
R1
RXC
R2
RXD
R3
LTC1545 RTS D1 RTS
DTR
D2
D3
DCD
R1
DSR
R2
CTS
R3
LL TM RI RL
D4 R4 R5 D5
Figure 9. Complete Multiprotocol Interface in EIA530 Mode
The internal pull-up current sources will ensure a binary 1 when a pin is left unconnected and that the LTC1543/ LTC1545 and the LTC1344A enter the no-cable mode when the cable is removed. In the no-cable mode the LTC1543/LTC1545 supply current drops to less than 200A and all LTC1543/LTC1545 driver outputs and LTC1344A resistive terminations are forced into a high impedance state.
8
U
W
U
U
DCE
LTC1543 R3 SERIAL CONTROLLER TXD
SCTE
103
R2
SCTE
R1
103
TXC
D3
TXC
103
RXC
D2
RXC
103
RXD
D1
RXD
LTC1545 R3 RTS
DTR
R2
DTR
R1
DCD
D3
DCD
DSR
D2
DSR
CTS LL TM RI RL
D1
CTS
R4 D4 D5 R5
LL TM RI RL
1545 F09
The mode selection may also be accomplished by using jumpers to connect the mode pins to ground or VCC. Cable Termination Traditional implementations have included switching resistors with expensive relays, or requiring the user to change termination modules every time the interface standard has changed. Custom cables have been used
LTC1545
APPLICATIONS INFORMATION
LATCH LTC1344A DCE/ DTE M2 22 (DATA) M0 LTC1543 M1 M2 DCE/DTE 11 12 13 14 23 M1 M0 (DATA) 24 1 CONNECTOR 21
DCE/DTE M2 M1 LTC1545 M0 D4ENB R4EN (DATA)
14 13 12 11 15 16 10k
Figure 10: Single Port DCE V.35 Mode Selection in the Cable
with the termination in the cable head or separate terminations are built on the board and a custom cable routes the signals to the appropriate termination. Switching the terminations with FETs is difficult because the FETs must remain off even though the signal voltage is beyond the supply voltage for the FET drivers or the power is off. Using the LTC1344A along with the LTC1543/LTC1545 solves the cable termination switching problem. Via software control, the LTC1344A provides termination for the V.10 (RS423), V.11 (RS422), V.28 (RS232) and V.35 electrical protocols. V.10 (RS423) Interface A typical V.10 unbalanced interface is shown in Figure 11. A V.10 single-ended generator output A with ground C is connected to a differential receiver with inputs A' connected to A, and input C' connected to the signal return ground C. Usually, no cable termination is required for V.10 interfaces, but the receiver inputs must be compliant with the impedance curve shown in Figure 12.
U
W
U
U
NC NC
VCC
CABLE
1545 F10
The V.10 receiver configuration in the LTC1545 is shown in Figure 13. In V.10 mode switch S3 inside the LTC1545 is turned off. The noninverting input is disconnected inside the LTC1545 receiver and connected to ground.The cable termination is then the 30k input impedance to ground of the LTC1545 V.10 receiver. V.11 (RS422) Interface A typical V.11 balanced interface is shown in Figure 14. A V.11 differential generator with outputs A and B with ground C is connected to a differential receiver with ground C', inputs A' connected to A, B' connected to B. The V.11 interface has a differential termination at the receiver end that has a minimum value of 100. The termination resistor is optional in the V.11 specification, but for the high speed clock and data lines, the termination is required to prevent reflections from corrupting the data. The receiver inputs must also be compliant with the impedance curve shown in Figure 12.
9
LTC1545
APPLICATIONS INFORMATION
GENERATOR BALANCED INTERCONNECTING CABLE LOAD CABLE TERMINATION A A' RECEIVER
A GENERATOR BALANCED INTERCONNECTING CABLE LOAD CABLE TERMINATION A' 100 MIN RECEIVER
C
C'
Figure 11. Typical V.10 Interface
IZ
-10V
-3V VZ 3V 10V
B' C'
-3.25mA
Figure 12. V.10 Receiver Input Impedance
A'
A R8 6k S3 R5 20k R6 10k
LTC1545
RECEIVER
B'
B
R4 20k
R7 10k
C'
GND
1545 F13
Figure 13. V.10 Receiver Configuration
10
U
W
U
U
B
1545 F11
B' C'
C
1545 F14
Figure 14. Typical V.11 Interface
A' A
3.25mA
R1 51.5 S1 S2 R2 51.5
LTC1344A
R8 6k S3
R5 20k R6 10k
LTC1543 LTC1545
RECEIVER
R3 124
B
R4 20k
R7 10k
GND
1545 F15
Figure 15. V.11 Receiver Configuration
1545 F12
In V.11 mode, all switches are off except S1 inside the LTC1344A which connects a 103 differential termination impedance to the cable as shown in Figure 15. V.28 (RS232) Interface A typical V.28 unbalanced interface is shown in Figure 16. A V.28 single-ended generator output A with ground C is connected to a single-ended receiver with input A' connected to A, ground C' connected via the signal return ground C. In V.28 mode all switches are off except S3 inside the LTC1543/LTC1545 which connects a 6k (R8) impedance to ground in parallel with 20k (R5) plus 10k (R6) for a combined impedance of 5k as shown in Figure 17. The noninverting input is disconnected inside the LTC1543/ LTC1545 receiver and connected to a TTL level reference voltage for a 1.4V receiver trip point.
LTC1545
APPLICATIONS INFORMATION
GENERATOR BALANCED INTERCONNECTING CABLE LOAD CABLE TERMINATION A A' RECEIVER
C
C'
Figure 16. Typical V.28 Interface
A' A R1 51.5 S1 S2 R2 51.5 B' C' GND
1545 F17
LTC1344A
R8 6k S3
R5 20k R6 10k
RECEIVER
R3 124
B
R4 20k
R7 10k
Figure 17. V.28 Receiver Configuration
GENERATOR
BALANCED INTERCONNECTING CABLE
LOAD CABLE TERMINATION RECEIVER
A 50
A' 50
125
125
50 B C B' C'
50
A LTC1344A
Figure 18. Typical V.35 Interface
V.35 Interface A typical V.35 balanced interface is shown in Figure 18. A V.35 differential generator with outputs A and B with ground C is connected to a differential receiver with ground C', inputs A' connected to A, B' connected to B. The
C1 100pF
U
W
U
U
V.35 interface requires a T or delta network termination at the receiver end and the generator end. The receiver differential impedance measured at the connector must be 100 10, and the impedance between shorted terminals (A' and B') and ground C' must be 150 15. In V.35 mode, both switches S1 and S2 inside the LTC1344A are on, connecting the T network impedance as shown in Figure 19. Both switches in the LTC1543 are off. The 30k input impedance of the receiver is placed in parallel with the T network termination, but does not affect the overall input impedance significantly. The generator differential impedance must be 50 to 150 and the impedance between shorted terminals (A and B) and ground C must be 150 15. For the generator termination, switches S1 and S2 are both on and the top side of the center resistor is brought out to a pin so it can be bypassed with an external capacitor to reduce common mode noise as shown in Figure 20.
A' A R1 51.5 S1 S2 R2 51.5 B' C' GND
1545 F19
1545 F16
LTC1543 LTC1545
LTC1543 R8 6k S3 R5 20k R6 10k RECEIVER
LTC1344A
R3 124
B
R4 20k
R7 10k
Figure 19. V.35 Receiver Configuration
1545 F18
51.5 S1 ON
V.35 DRIVER 124
S2 ON
51.5 B C
1545 F20
Figure 20. V.35 Driver Using the LTC1344A
11
LTC1545
APPLICATIONS INFORMATION
Any mismatch in the driver rise and fall times or skew in the driver propagation delays will force current through the center termination resistor to ground, causing a high frequency common mode spike on the A and B terminals. The common mode spike can cause EMI problems that are reduced by capacitor C1 which shunts much of the common mode energy to ground rather than down the cable. No-Cable Mode The no-cable mode (M0 = M1 = M2 = D4ENB = 1, R4EN = 0) is intended for the case when the cable is disconnected from the connector. The charge pump, bias circuitry, drivers and receivers are turned off, the driver outputs are forced into a high impedance state, and the supply current drops to less than 200A. Charge Pump The LTC1543 uses an internal capacitive charge pump to generate VDD and VEE as shown in Figure 21. A voltage doubler generates about 8V on VDD and a voltage inverter generates about - 7.5V for VEE. Four 1F surface mounted tantalum or ceramic capacitors are required for C1, C2, C3 and C4. The VEE capacitor C5 should be a minimum of 3.3F. All capacitors are 16V and should be placed as close as possible to the LTC1543 to reduce EMI.
3 C3 1F 2 C1 1F 1 4 C4 1F
1545 F21
VDD C1+ LTC1543 C1- VCC
C2 + C2 - VEE GND
28 27 26 25 C5 3.3F C2 1F
5V
Figure 21. Charge Pump
Receiver Fail-Safe All LTC1543/LTC1545 receivers feature fail-safe operation in all modes. If the receiver inputs are left floating or shorted together by a termination resistor, the receiver output will always be forced to a logic high.
12
U
+
W
U
U
DTE vs DCE Operation The DCE/DTE pin acts as an enable for Driver 3/Receiver 1 in the LTC1543, and Driver 3/Receiver 1 in the LTC1545. The LTC1543/LTC1545 can be configured for either DTE or DCE operation in one of two ways: a dedicated DTE or DCE port with a connector of appropriate gender or a port with one connector that can be configured for DTE or DCE operation by rerouting the signals to the LTC1543/LTC1545 using a dedicated DTE cable or dedicated DCE cable. A dedicated DTE port using a DB-25 male connector is shown in Figure 22. The interface mode is selected by logic outputs from the controller or from jumpers to either VCC or GND on the mode select pins. A dedicated DCE port using a DB-25 female connector is shown in Figure 23. A port with one DB-25 connector, but can be configured for either DTE or DCE operation is shown in Figure 24. The configuration requires separate cables for proper signal routing in DTE or DCE operation. For example, in DTE mode, the TXD signal is routed to Pins 2 and 14 via Driver 1 in the LTC1543. In DCE mode, Driver 1 now routes the RXD signal to Pins 2 and 14. Compliance Testing A European standard EN 45001 test report is available for the LTC1343/LTC1545/LTC1344A chipset. A copy of the test report is available from LTC or TUV Telecom Services Inc. (formerly Detecon Inc.) The title of the report is: Test Report No. NET2/071601/98. The address of TUV Telecom Services Inc. is: TUV Telecom Services Inc. Suite 107 1775 Old Highway 8 St. Paul, MN 55112 USA Tel. +1 (612) 639-0775 Fax. +1 (612) 639-0873
LTC1545
TYPICAL APPLICATIONS
C6 C7 C8 100pF 100pF 100pF 3 VCC 5V 14 3 C3 1F 1 C1 1F 2 4 C5 1F TXD SCTE 5 LTC1543 D1 D2 CHARGE PUMP 28 27 26 25 C4 3.3F C2 1F 2 C12 1F 5467 9 10 VEE
DCE/DTE M2 M1 M0
24 23 22 21
6 7
D3 20 15 12 17 9 3 16 7 1
TXC
8
R1
19 18
RXC RXD
9
R2
17 16
10 11 12 13 14 M0 M1 M2
R3
15
DCE/DTE
C10 1F
VCC 5V
C9 1F
1,19 VCC 2,20 VDD 3 D1
VEE GND
36 35 34 C11 1F 4 19 20 23
RTS
33 32
DTR
4
D2
31
5
D3 LTC1545 30 29 28 R2 27 26 R3 D4 R4 R5 D5 M0 M1 M2 DCE/DTE R4EN D4ENB 25 24 23 22 21 15 16 8 10 6 22 5 13 18 * 25 21
DCD
6 7 8 9 10 17 18 11 12 13 14
R1
DSR CTS LL RI TM RL
M0 M1 M2
Figure 22. Controller-Selectable Multiprotocol DTE Port with DB-25 Connector
+
U
8
11
12
13 LTC1344A
C13 1F
VCC
LATCH
21
16 15 18 17 19 20 22 23 24 1 2 14 24 11 TXD A (103) TXD B SCTE A (113) SCTE B
TXC A (114) TXC B RXC A (115) RXC B RXD A (104) RXD B SG SHIELD
DB-25 MALE CONNECTOR
RTS A (105) RTS B DTR A (108) DTR B
DCD A (109) DCD B DSR A (107) DSR B CTS A (106) CTS B LL (141) RI (125) TM (142) RL (140)
NC
*OPTIONAL
1544 F22
13
LTC1545
TYPICAL APPLICATIONS U
C6 C7 C8 100pF 100pF 100pF
3 VCC 5V 14 3 C3 1F 1 C1 1F C5 1F RXD RXC 5 2 4 LTC1543 D1 D2 CHARGE PUMP 28 27 26 25 C4 3.3F C2 1F 2 C12 1F VEE C13 1F VCC
8
11
12
13 LTC1344A
LATCH
21
DCE/DTE
M2
M1
5467
9 10
16 15 18 17 19 20 22 23 24 1 VCC 3 16 17 9 RXD A (104) RXD B RXC A (115) RXC B
24 23 22 21
6
7
D3 20 15 12 24 11 2 14 7 1
M0
TXC
8
R1
19 18
SCTE TXD
9
R2
17 16
10 11 12 13 NC 14 M0 M1 M2
R3
15
DCE/DTE
C10 1F
VCC 5V
C9 1F
1,19 VCC 2,20 VDD 3 D1
VEE GND
36 35 34 C11 1F 5 13 6 22
CTS
33 32
DSR
4
D2
31
5
D3 LTC1545 30 29 28 R2 27 26 R3 D4 R4 R5 D5 M0 M1 M2 DCE/DTE R4EN D4ENB 25 24 23 22 21 15 16 8 10 20 23
DCD DTR
6 7 8 9 10 17 18 11 12 13 NC 14
R1
RTS RI LL RL TM
M0 M1 M2
Figure 23. Controller-Selectable DCE Port with DB-25 Connector
14
+
TXC A (114) TXC B SCTE A (113) SCTE B TXD A (103) TXD B SGND (102) SHIELD (101)
DB-25 FEMALE CONNECTOR
CTS A (106) CTS B DSR A (107) DSR B
DCD A (109) DCD B DTR A (108)
DTR B 4 RTS A (105) 19 RTS B * 18 21 25 RI (125) LL (141) RL (140) TM (142)
NC *OPTIONAL
1544 F23
LTC1545
TYPICAL APPLICATIONS U
M0 M1 1 M0 M1 M2 DCE/DTE R4EN C6 C7 C8 100pF 100pF 100pF
3 VCC 5V 14 3 C3 1F 1 C1 1F 2 4 C5 1F DTE_TXD/DCE_RXD DTE_SCTE/DCE_RXC 5 LTC1543 D1 D2 CHARGE PUMP 28 27 26 25 C2 1F 2 C4 3.3F C12 1F VEE C13 1F VCC
8
11
12
13 LTC1344A
LATCH
21
DCE/DTE
M2
M1
5467
9 10
16 15 18 17 19 20 22 23 24 1 2 14 24 11 DTE TXD A TXD B SCTE A SCTE B DCE RXD A RXD B RXC A RXC B
24 23 22 21
6 7
D3 20 15 12 17 9 3 16 7
M0
DTE_TXC/DCE_TXC
8
R1
19 18
DTE_RXC/DCE_SCTE
9
R2
17 16
DTE_RXD/DCE_TXD
10 11 12
R3
15
13 M2 14 DCE/DTE
C10 1F
VCC 5V
C9 1F
1,19 VCC 2,20 VDD 3 D1
VEE GND
36 35 34 C11 1F 4 19 20 23
DTE_RTS/DCE_CTS
33 32
DTE_DTR/DCE_DSR
4
D2
31
5
D3 LTC1545 30 29 28 R2 27 26 R3 D4 R4 R5 D5 D4ENB 25 24 23 22 21 15 16 8 10 6 22 5 13 18 * 25 21
DTE_DCD/DCE_DCD DTE_DSR/DCE_DTR
6 7 8 9 10 17 18 11 12 13 14
R1
DTE_CTS/DCE_RTS DTE_LL/DCE_RI DTE_RI/DCE_LL DTE_TM/DCE_RL DTE_RL/DCE_TM
DCE/DTE M0 M1 M2
Figure 24. Controller-Selectable Multiprotocol DTE/DCE Port with DB-25 Connector
+
TXC A TXC B RXC A RXC B RXD A RXD B SG SHIELD
TXC A TXC B SCTE A SCTE B TXD A TXD B
DB-25 CONNECTOR
RTS A RTS B DTR A DTR B
CTS A CTS B DSR A DSR B
DCD A DCD B DSR A DSR B CTS A CTS B LL RI TM RL
DCD A DCD B DTR A DTR B RTS A RTS B RI LL RL TM
NC *OPTIONAL
1544 F24
15
LTC1545
PACKAGE DESCRIPTION
0.205 - 0.212** (5.20 - 5.38)
0.005 - 0.009 (0.13 - 0.22)
0.022 - 0.037 (0.55 - 0.95)
*DIMENSIONS DO NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE **DIMENSIONS DO NOT INCLUDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE
RELATED PARTS
PART NUMBER
LTC1321 LTC1334 LTC1343 LTC1344A LTC1345 LTC1346A LTC1543 LTC1544 LTC1387
DESCRIPTION
Dual RS232/RS485 Transceiver Single 5V RS232/RS485 Multiprotocol Transceiver Software-Selectable Multiprotocol Transceiver Software-Selectable Cable Terminator Single Supply V.35 Transceiver Dual Supply V.35 Transceiver Software-Selectable Multiprotocol Transceiver Software-Selectable Multiprotocol Transceiver Single 5V RS232/RS485 Multiprotocol Transceiver
16
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408)432-1900 q FAX: (408) 434-0507 q www.linear-tech.com
U
Dimensions in inches (millimeters) unless otherwise noted. G Package 36-Lead Plastic SSOP (0.209)
(LTC DWG # 05-08-1640)
0.499 - 0.509* (12.67 - 12.93) 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 20 19
0.301 - 0.311 (7.65 - 7.90)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 0.068 - 0.078 (1.73 - 1.99)
0 - 8
0.0256 (0.65) BSC
0.010 - 0.015 (0.25 - 0.38)
0.002 - 0.008 (0.05 - 0.21)
G36 SSOP 1196
COMMENTS
Two RS232 Driver/Receiver Pairs or Two RS485 Driver/Receiver Pairs Two RS232 Driver/Receiver Pairs or Four RS232 Driver/Receiver Pairs 4-Driver/4-Receiver for Data and Clock Signals Perfect for Terminating the LTC1543 3-Driver/3-Receiver for Data and Clock Signals 3-Driver/3-Receiver for Data and Clock Signals Companion to LTC1544/LTC1545 for Data and Clock Signals 4-Driver/4-Receiver for Control Signals Two RS232 Driver Pairs or One RS485 Driver/Receiver Pair
1545i LT/TP 1298 4K * PRINTED IN USA
(c) LINEAR TECHNOLOGY CORPORATION 1998

▲Up To Search▲

Price & Availability of LTC1545

	To Download LTC1545 Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .