Datasheet

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LTC1544

Software-Selectable

Multiprotocol Transceiver

D2 D1

LTC1544

RTS

DTRDSR DCDCTS

R2 R1R4

LTC1543

TXDSCTETXC

RXCRXD

21424111512179314192062322513 81018 7 16

1544 TA01

LTC1344A

R1R3

TXD A (103)

TXD B

SCTE A (113)

SCTE B

RXC A (115)

RXC B

RXD A (104)

RXD B

RTS A (105)

RTS B

DTR A (108)

DTR B

CTS A (106)

CTS B

LL A (141)

SG (102)

SHIELD (101)

DB-25 CONNECTOR

TXC A (114)

TXC B

DCD A (109)

DCD B

DSR A (107)

DSR B

DTE or DCE Multiprotocol Serial Interface with DB-25 Connector

, LTC and LT are registered trademarks of Linear Technology Corporation.

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Data Networking

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CSU and DSU

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Data Routers

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Software-Selectable Transceiver Supports:

RS232, RS449, EIA530, EIA530-A, V.35, V.36, X.21

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TUV/Detecon Inc. Certified NET1 and NET2

Compliant (Test Report No. NET2/102201/97)

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TBR2 Compliant (Test Report No. CTR2/022701/98)

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Software-Selectable Cable Termination Using

the LTC1344A

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Complete DTE or DCE Port with LTC1543, LTC1344A

or LTC1546 with Integrated Termination

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Operates from Single 5V Supply with LTC1543

The LTC

1544 is a 4-driver/4-receiver multiprotocol trans-

ceiver. The LTC1544 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 for the LTC1543 may be

implemented using the LTC1344A software-selectable cable

termination chip or by using existing discrete designs. The

LTC1546 includes software-selectable cable termination on-

chip.

The LTC1544 runs from a 5V supply and the charge pump on

the LTC1543 or LTC1546. The part is available in a 28-lead

SSOP surface mount package.

FEATURES

DESCRIPTIO

APPLICATIO S

TYPICAL APPLICATIO

Summary of content (20 pages)

PAGE 1
LTC1544 Software-Selectable Multiprotocol Transceiver U FEATURES ■ ■ ■ ■ ■ ■ DESCRIPTIO The LTC®1544 is a 4-driver/4-receiver multiprotocol transceiver. The LTC1544 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 for the LTC1543 may be implemented using the LTC1344A software-selectable cable termination chip or by using existing discrete designs.
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LTC1544 W W W AXI U U ABSOLUTE RATI GS U U W PACKAGE/ORDER I FOR ATIO (Note 1) 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.
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LTC1544 ELECTRICAL CHARACTERISTICS The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VCC = 5V, VDD = 8V, VEE = – 7V for V.28, – 5.5V for V.10, V.11 (Notes 2, 3) SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Logic Inputs and Outputs VIH Logic Input High Voltage VIL Logic Input Low Voltage IIN Logic Input Current ● 2 V ● 0.
PAGE 4
LTC1544 ELECTRICAL CHARACTERISTICS The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VCC = 5V, VDD = 8V, VEE = – 7V for V.28, – 5.5V for V.10, V.11 (Notes 2, 3) SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS VO Output Voltage Open Circuit, RL = 3.9k ● VT Output Voltage RL = 450Ω (Figure 3) RL = 450Ω (Figure 3) ● ISS Short-Circuit Current VO = GND IOZ Output Leakage Current – 0.25V ≤ VO ≤ 0.
PAGE 5
LTC1544 U U U PI FU CTIO S VCC (Pin 1): Positive Supply for the Transceivers. 4.75V ≤ VCC ≤ 5.25V. Connect a 1µF capacitor to ground. INVERT (Pin 15): TTL Level Mode Select Input with PullUp to VCC. VDD (Pin 2): Positive Supply Voltage for V.28. Connect to VDD Pin 3 on LTC1543 or 8V supply. Connect a 1µF capacitor to ground. D4/R4 A (Pin 16): Receiver 4 Inverting Input and Driver 4 Output. D1 (Pin 3): TTL Level Driver 1 Input. R3 B (Pin 17): Receiver 3 Noninverting Input.
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LTC1544 TEST CIRCUITS D D A A A R 15pF RL CL 1544 F04 1544 F03 Figure 4. V.10/V.28 Receiver Test Circuit Figure 3. V.10/V.28 Driver Test Circuit U W ODE SELECTIO LTC1544 MODE NAME M2 M1 M0 DCE/DTE INVERT D1 D2 D3 R1 R2 R3 D4 R4 Not Used (Default V.11) 0 0 0 0 0 V.11 V.11 Z V.11 V.11 V.11 Z V.10 RS530A 0 0 1 0 0 V.11 V.10 Z V.11 V.10 V.11 Z V.10 RS530 0 1 0 0 0 V.11 V.11 Z V.11 V.11 V.11 Z V.10 X.21 0 1 1 0 0 V.11 V.11 Z V.11 V.
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LTC1544 U W W SWITCHI G TI E WAVEFOR S 5V f = 1MHz : t r ≤ 10ns : t f ≤ 10ns 1.5V D 0V 1.5V t PHL t PLH VO B–A –VO 90% 50% 10% tr 90% VDIFF = V(A) – V(B) 1/2 VO 50% 10% tf A VO B t SKEW t SKEW 1544 F05 Figure 5. V.11, V.35 Driver Propagation Delays VOD2 B–A –VOD2 f = 1MHz : t r ≤ 10ns : t f ≤ 10ns 0V INPUT t PLH 0V t PHL VOH R VOL OUTPUT 1.5V 1.5V 1544 F06 Figure 6. V.11, V.35 Receiver Propagation Delays 3V 1.5V 1.
PAGE 8
LTC1544 U U W U APPLICATIONS INFORMATION Overview 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 LTC1544 is used to generate the control signals along with LL (Local Loop-back).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.
PAGE 9
LTC1544 U U W U APPLICATIONS INFORMATION 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.
PAGE 10
LTC1544 U U W U APPLICATIONS INFORMATION Cable Termination Traditional implementations have included switching resistors with expensive relays, or requiring the user to change termination modules every time the interface standard has changed. Custom cables have been used with the termination in the cable head or separate terminations are built on the board and a custom cable routes the signals to the appropriate termination.
PAGE 11
LTC1544 U U W U APPLICATIONS INFORMATION V.11 (RS422) Interface V.28 (RS232) 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 100Ω. The termination resistor is optional in the V.
PAGE 12
LTC1544 U U W U APPLICATIONS INFORMATION 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 V.35 interface requires a T or delta network termination at the receiver end and the generator end.
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LTC1544 U W U U APPLICATIONS INFORMATION The generator differential impedance must be 50Ω to 150Ω and the impedance between shorted terminals (A and B) and ground C must be 150Ω ±15Ω. 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 LTC1344A V.
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LTC1544 U W U U APPLICATIONS INFORMATION The LTC1543/LTC1544 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/LTC1544 using a dedicated DTE cable or dedicated DCE cable. A dedicated DTE port using a DB-25 male connector is shown in Figure 22.
PAGE 15
LTC1544 U TYPICAL APPLICATIO S C6 C7 C8 100pF 100pF 100pF 3 8 11 12 13 LTC1344A VCC 5V 14 4 25 C5 1µF LTC1543 5 TXD D1 6 SCTE D2 7 11 12 13 14 C9 1µF RTS DTR R2 10 RXD C10 1µF R1 9 RXC R3 CTS LL 24 2 23 14 22 24 21 11 20 15 19 12 18 17 17 9 16 3 15 16 1 VEE GND D1 D2 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 28 C11 1µF 27 26 4 25 19 24 20 23 23 RTS A (105) RTS
PAGE 16
LTC1544 U TYPICAL APPLICATIO S C6 C7 C8 100pF 100pF 100pF 3 8 11 12 13 LTC1344A VCC 5V 14 4 25 C5 1µF LTC1543 5 RXD RXC D2 7 R2 10 TXD 11 12 13 NC C10 1µF R1 9 SCTE C9 1µF 14 5 4 6 7 9 10 16 15 18 17 19 20 22 23 24 1 VCC 16 22 17 21 9 R3 20 15 19 12 18 24 17 11 16 2 15 14 M0 7 M1 M2 1 DCE/DTE 1 VCC 2 VDD 3 VEE GND D1 4 DSR D2 5 LTC1544 R1 7 DTR R2 8 RTS R3 10 LL R4 9 11 12 13 NC 14 RXD B RXC A (115) RXC B TXC A (114) TXC B SCTE A (113) S
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LTC1544 U TYPICAL APPLICATIO S C6 C7 C8 100pF 100pF 100pF 3 8 11 12 13 LTC1344A VCC 5V 14 LTC1543 5 DTE_TXD/DCE_RXD D1 6 DTE_SCTE/DCE_RXC D2 7 R1 9 DTE_RXC/DCE_SCTE R2 10 DTE_RXD/DCE_TXD 11 5 4 6 7 9 10 16 15 18 17 19 20 22 23 24 1 24 2 23 14 22 24 21 11 R3 20 15 19 12 18 17 17 9 16 3 15 16 M0 7 12 M1 13 M2 14 DCE/DTE C10 1µF DTE_RTS/DCE_CTS DTE_DTR/DCE_DSR C9 1µF 1 VCC 1 VCC 2 VDD 3 VEE GND D1 4 D2 5 DTE_DSR/DCE_DTR DTE_CTS/DCE_RTS DTE_LL/DCE_
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LTC1544 U C6 C7 C8 100pF 100pF 100pF TYPICAL APPLICATIO S 3 8 11 12 13 LTC1344A VCC 5V 14 44 C5 1µF 41 D1 D2 7 DTE_SCTE/DCE_RXC 5 4 6 7 9 10 16 15 18 17 19 20 22 23 24 1 LTC1343 6 DTE_TXD/DCE_RXD VEE C12 1µF 8 5 DTE_LL/DCE_TM 2 C4 3.
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LTC1544 U TYPICAL APPLICATIO S C6 C7 C8 100pF 100pF 100pF 3 8 11 12 13 LTC1344A VCC 5V 14 4 25 C5 1µF LTC1543 5 DTE_TXD/DCE_RXD D2 7 R1 9 DTE_RXC/DCE_SCTE R2 10 DTE_RXD/DCE_TXD 11 12 NC 13 14 VEE C12 1µF 5 4 6 7 9 10 16 15 18 17 19 20 22 23 24 1 VCC 2 23 14 22 24 21 11 DTE DCE TXD A RXD A TXD B RXD B SCTE A RXC A SCTE B RXC B TXC A TXC A TXC B TXC B RXC A SCTE A RXC B SCTE B RXD A TXD A RXD B TXD B D3 8 DTE_TXC/DCE_TXC 2 C4 3.
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LTC1544 U PACKAGE DESCRIPTIO Dimensions in inches (millimeters) unless otherwise noted. G Package 28-Lead Plastic SSOP (0.209) (LTC DWG # 05-08-1640) 10.07 – 10.33* (0.397 – 0.407) 28 27 26 25 24 23 22 21 20 19 18 17 16 15 7.65 – 7.90 (0.301 – 0.311) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 5.20 – 5.38** (0.205 – 0.212) 1.73 – 1.99 (0.068 – 0.078) 0° – 8° 0.13 – 0.22 (0.005 – 0.009) 0.55 – 0.95 (0.022 – 0.037) NOTE: DIMENSIONS ARE IN MILLIMETERS *DIMENSIONS DO NOT INCLUDE MOLD FLASH.