Datasheet LTC1544 Datasheet (Linear Technology)

FEATURES

■

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. NET2/102201/97)

■

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

■

Software-Selectable Cable Termination Using the LTC1344A

■

Complete DTE or DCE Port with LTC1543, LTC1344A or LTC1546 with Integrated Termination

■

Operates from Single 5V Supply with LTC1543

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APPLICATIO S

■

Data Networking

■

CSU and DSU

■

Data Routers

LTC1544

Software-Selectable

Multiprotocol Transceiver

U

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. The LTC1546 includes software-selectable cable termination onchip.

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.

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

TYPICAL APPLICATIO

DTE or DCE Multiprotocol Serial Interface with DB-25 Connector

LL

LTC1544

D4

CTS B

LL A (141)

R3

CTS A (106)

R2 R1R4

DSR A (109)

DSR B

D3

DCD A (107)

DCD B

U

DTRDSR DCDCTS

D2 D1

DTR B

RTS

RTS A (105)

RTS B

DTR A (108)

RXD B

SG (102)

SHIELD (101)

RXCRXD

R2

RXC A (115)

RXC B

RXD A (104)

LTC1543

R1R3

D3

TXC A (114)

TXC B

D2

SCTE A (113)

SCTE B

TXDSCTETXC

D1

TXD A (103)

TXD B

LTC1344A

21424111512179314192062322513 81018 7 16

DB-25 CONNECTOR

1544 TA01

1

LTC1544

WWWU

ABSOLUTE AXI U RATI GS

(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................................ –0.3V 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

LTC1544CG .............................................0°C to 70°C

LTC1544IG ........................................ – 40°C to 85°C

Storage Temperature Range ................ –65°C to 150°C

Lead Temperature (Soldering, 10 sec)................. 300°C

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PACKAGE/ORDER I FOR ATIO

TOP VIEW

1

V

CC

2

V

DD

3

M0

M1

M2

DCE/DTE

D1

4

D2

5

D3

6

R1

7

R2

8

R3

9

D4

10

R4

11

12

13

14

T

JMAX

D1

D2

D3

R1

R2

R3

D4

R4

G PACKAGE

28-LEAD PLASTIC SSOP

= 150°C, θJA = 65°C/W

Consult factory for Military grade parts.

28

27

26

25

24

23

22

21

20

19

18

17

16

15

V

EE

GND

D1 A

D1 B

D2 A

D2 B

D3/R1 A

D3/R1 B

R2 A

R2 B

R3 A

R3 B

D4/R4 A

INVERT

ORDER PART

NUMBER

LTC1544CG LTC1544IG

ELECTRICAL CHARACTERISTICS

The ● denotes specifications which apply over the full operating tempera-

ture 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 Supplies

I

CC

I

EE

I

DD

P

D

VCC Supply Current (DCE Mode, RS530, RS530-A, X.21 Modes, No Load 2.7 mA All Digital Pins = GND or V

) RS530, RS530-A, X.21 Modes, Full Load ● 95 120 mA

CC

V.28 Mode, No Load V.28 Mode, Full Load No-Cable Mode

● 12 mA

● 10 200 µA

VEE Supply Current (DCE Mode, RS530, RS530-A, X.21 Modes, No Load 2.1 mA All Digital Pins = GND or V

V

= –5.6V (RS530, RS530-A Modes) RS530-A, Full Load 25 mA

EE

= –8.46V (V.28 Mode) V.28 Mode, No Load 1 mA

V

EE

) RS530, X.21 Modes, Full Load 14 mA

CC

V.28 Mode, Full Load 12 mA No-Cable Mode 10 µA

VDD Supply Current (DCE Mode, RS530, RS530-A, X.21 Modes, NoLoad 0.2 mA All Digital Pins = GND or V

= 8.73V V.28 Mode, No Load 1 mA

V

DD

) RS530, RS530-A, X.21 Modes, Full Load 0.2 mA

CC

V.28 Mode, Full Load 12 mA No-Cable Mode 10 µA

Internal Power Dissipation (DCE Mode, RS530, RS530-A, X.21 Modes, Full Load 300 mW (All Digital Pins = GND or V

) V.28 Mode, Full Load 54 mW

CC

2

LTC1544

ELECTRICAL CHARACTERISTICS

The ● denotes specifications which apply over the full operating tempera-

ture 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

V

IH

V

IL

I

IN

V

OH

V

OL

I

OSR

I

OZR

V.11 Driver

V

ODO

V

ODL

∆V

OD

V

OC

∆V

OC

I

SS

I

OZ

tr, t

f

t

PLH

t

PHL

∆t Input to Output Difference, t

t

SKEW

V.11 Receiver

V

TH

∆V

TH

I

IN

R

IN

tr, t

f

t

PLH

t

PHL

∆t Input to Output Difference, t

Logic Input High Voltage ● 2V Logic Input Low Voltage ● 0.8 V Logic Input Current D1, D2, D3, D4 ● ±10 µA

M0, M1, M2, DCE, INVERT = GND (LTC1544C) M0, M1, M2, DCE, INVERT = GND (LTC1544I) M0, M1, M2, DCE, INVERT = V

CC

● –100 –50 – 30 µA

● –120 –50 – 30 µA

● ±10 µA

Output High Voltage IO = –4mA ● 3 4.5 V Output Low Voltage IO = 4mA ● 0.3 0.8 V Output Short-Circuit Current 0V ≤ VO ≤ V

CC

Three-State Output Current M0 = M1 = M2 = VCC, 0V ≤ VO ≤ V

CC

● –50 40 50 mA

±1 µA

Open Circuit Differential Output Voltage RL = 1.95k (Figure 1) ● ±5V Loaded Differential Output Voltage RL = 50Ω (Figure 1) 0.5V

R

= 50Ω (Figure 1) ● ±2V

L

ODO

0.67V

ODO

Change in Magnitude of Differential RL = 50Ω (Figure 1) ● 0.2 V Output Voltage

Common Mode Output Voltage RL = 50Ω (Figure 1) ● 3V Change in Magnitude of Common Mode RL = 50Ω (Figure 1) ● 0.2 V

Output Voltage Short-Circuit Current V

= GND ±150 mA

OUT

Output Leakage Current –0.25V ≤ VO ≤ 0.25V, Power Off or ● ±1 ±100 µA

No-Cable Mode or Driver Disabled

Rise or Fall Time LTC1544C (Figures 2, 5) ● 21525 ns

LTC1544I (Figures 2, 5)

● 21535 ns

Input to Output LTC1544C (Figures 2, 5) ● 20 40 65 ns

LTC1544I (Figures 2, 5)

● 20 40 75 ns

Input to Output LTC1544C (Figures 2, 5) ● 20 40 65 ns

● 20 40 75 ns

● 0317 ns

PLH

LTC1544I (Figures 2, 5)

– t

 LTC1544C (Figures 2, 5) ● 0312 ns

PHL

LTC1544I (Figures 2, 5)

Output to Output Skew (Figures 2, 5) 3 ns

Input Threshold Voltage –7V ≤ VCM ≤ 7V ● –0.2 0.2 V Input Hysteresis –7V ≤ VCM ≤ 7V ● 15 40 mV Input Current (A, B) –10V ≤ V Input Impedance –10V ≤ V

≤ 10V ● ±0.66 mA

A,B

≤ 10V ● 15 30 kΩ

A,B

Rise or Fall Time (Figures 2, 6) 15 ns Input to Output LTC1544C (Figures 2, 6) ● 50 80 ns

LTC1544I (Figures 2, 6)

● 50 90 ns

Input to Output LTC1544C (Figures 2, 6) ● 50 80 ns

● 50 90 ns

● 0421 ns

PLH

LTC1544I (Figures 2, 6)

– t

 LTC1544C (Figures 2, 6) ● 0416 ns

PHL

LTC1544I (Figures 2, 6)

V

3

LTC1544

ELECTRICAL CHARACTERISTICS

The ● denotes specifications which apply over the full operating tempera-

ture 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 V.10 Driver

V

O

V

T

I

SS

I

OZ

tr, t

f

t

PLH

t

PHL

V.10 Receiver

V

TH

∆V

TH

I

IN

R

IN

tr, t

f

t

PLH

t

PHL

∆t Input to Output Difference, t

V.28 Driver

V

O

I

SS

I

OZ

SR Slew Rate RL = 3k, CL = 2500pF (Figures 3, 7) ● 430V/µs t

PLH

t

PHL

V.28 Receiver

V

THL

V

TLH

∆V

TH

R

IN

tr, t

f

t

PLH

t

PHL

Output Voltage Open Circuit, RL = 3.9k ● ±4 ±6V Output Voltage RL = 450Ω (Figure 3) ● ±3.6 V

= 450Ω (Figure 3) 0.9V

R

L

O

Short-Circuit Current VO = GND ±150 mA Output Leakage Current –0.25V ≤ VO ≤ 0.25V, Power Off or ● ±0.1 ±100 µA

No-Cable Mode or Driver Disabled Rise or Fall Time RL = 450Ω, CL = 100pF (Figures 3, 7) 2 µs Input to Output RL = 450Ω, CL = 100pF (Figures 3, 7) 1 µs Input to Output RL = 450Ω, CL = 100pF (Figures 3, 7) 1 µs

Receiver Input Threshold Voltage ● –0.25 0.25 V Receiver Input Hysteresis ● 25 50 mV Receiver Input Current – 10V ≤ VA ≤ 10V ● ±0.66 mA Receiver Input Impedance –10V ≤ VA ≤ 10V ● 15 30 kΩ Rise or Fall Time (Figures 4, 8) 15 ns Input to Output (Figures 4, 8) 55 ns Input to Output (Figures 4, 8) 109 ns

– t

PLH

 (Figures 4, 8) 60 ns

PHL

Output Voltage Open Circuit ● ±10 V

R

= 3k (Figure 3) ● ±5 ±8.5 V

L

Short-Circuit Current VO = GND ● ±150 mA Output Leakage Current –0.25V ≤ VO ≤ 0.25V, Power Off or ● ±1 ±100 µA

No-Cable Mode or Driver Disabled

Input to Output RL = 3k, CL = 2500pF (Figures 3, 7) ● 1.3 2.5 µs Input to Output RL = 3k, CL = 2500pF (Figures 3, 7) ● 1.3 2.5 µs

Input Low Threshold Voltage ● 1.5 0.8 V Input High Threshold Voltage ● 2 1.6 V Receiver Input Hysterisis ● 0 0.1 0.3 V Receiver Input Impedance –15V ≤ VA ≤ 15V ● 357 kΩ Rise or Fall Time (Figures 4, 8) 15 ns Input to Output (Figures 4, 8) ● 60 100 ns Input to Output (Figures 4, 8) ● 150 450 ns

Note 1: Absolute Maximum Ratings are those beyond which the safety 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.

4

Note 3: All typicals are given for V –5.5V for V.10, V.11 and T

= 25°C.

A

= 5V, VDD = 8V, VEE = –7V for V.28,

CC

LTC1544

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PI FU CTIO S

VCC (Pin 1): Positive Supply for the Transceivers. 4.75V ≤ VCC ≤ 5.25V. Connect a 1µF capacitor to ground.

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.

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.

INVERT (Pin 15): TTL Level Mode Select Input with PullUp to VCC.

D4/R4 A (Pin 16): Receiver 4 Inverting Input and Driver 4 Output.

R3 B (Pin 17): Receiver 3 Noninverting Input. R3 A (Pin 18): Receiver 3 Inverting Input. R2 B (Pin 19): Receiver 2 Noninverting Input. R2 A (Pin 20): Receiver 2 Inverting Input. D3/R1 B (Pin 21): Receiver 1 Noninverting Input and

Driver 3 Noninverting Output. D3/R1 A (Pin 22): Receiver 1 Inverting Input and Driver 3

Inverting Output.

D2 B (Pin 23): Driver 2 Noninverting Output. D2 A (Pin 24): Driver 2 Inverting Output. D1 B (Pin 25): Driver 1 Noninverting Output.

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.

TEST CIRCUITS

A

R

L

50Ω

V

OD

V

R

OC

L

50Ω

B

1544 F01

D1 A (Pin 26): Driver 1 Inverting Output. GND (Pin 27): Ground. V

(Pin 28): Negative Supply Voltage. Connect to VEE Pin

EE

26 on LTC1543 or to – 8V supply. Connect a 1µF capacitor to ground.

C

L

B

R

L

100Ω

A

100pF

C 100pF

B

R

L

A

15pF

1544 F02

Figure 1. V.11 Driver Test Circuit

Figure 2. V.11 Driver/Receiver AC Test Circuit

5

LTC1544

TEST CIRCUITS

W

D

A

C

R

L

1544 F03

Figure 3. V.10/V.28 Driver Test Circuit

U

D

Figure 4. V.10/V.28 Receiver Test Circuit

A

R

15pF

1544 F04

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.11 V.11 Z V.10 V.35 1 0 0 0 0 V.28 V.28 Z V.28 V.28 V.28 Z V.28 RS449/V.36 1 0 1 0 0 V.11 V.11 Z V.11 V.11 V.11 Z V.10 V.28/RS232 1 1 0 0 0 V.28 V.28 Z V.28 V.28 V.28 Z V.28 No Cable 1 1 1 0 0 Z Z Z ZZZZ Z Not Used (Default V.11) 0 0 0 0 1 V.11 V.11 Z V.11 V.11 V.11 V.10 Z RS530A 0 0 1 0 1 V.11 V.10 Z V.11 V.10 V.11 V.10 Z RS530 0 1 0 0 1 V.11 V.11 Z V.11 V.11 V.11 V.10 Z X.21 0 1 1 0 1 V.11 V.11 Z V.11 V.11 V.11 V.10 Z V.35 1 0 0 0 1 V.28 V.28 Z V.28 V.28 V.28 V.28 Z RS449/V.36 1 0 1 0 1 V.11 V.11 Z V.11 V.11 V.11 V.10 Z V.28/RS232 1 1 0 0 1 V.28 V.28 Z V.28 V.28 V.28 V.28 Z No Cable 1 1 1 0 1 Z Z Z ZZZZ Z Not Used (Default V.11) 0 0 0 1 0 V.11 V.11 V.11 Z V.11 V.11 V.10 Z RS530A 0 0 1 1 0 V.11 V.10 V.11 Z V.10 V.11 V.10 Z RS530 0 1 0 1 0 V.11 V.11 V.11 Z V.11 V.11 V.10 Z X.21 0 1 1 1 0 V.11 V.11 V.11 Z V.11 V.11 V.10 Z V.35 1 0 0 1 0 V.28 V.28 V.28 Z V.28 V.28 V.28 Z RS449/V.36 1 0 1 1 0 V.11 V.11 V.11 Z V.11 V.11 V.10 Z V.28/RS232 1 1 0 1 0 V.28 V.28 V.28 Z V.28 V.28 V.28 Z No Cable 1 1 1 1 0 Z Z Z ZZZZ Z Not Used (Default V.11) 0 0 0 1 1 V.11 V.11 V.11 Z V.11 V.11 Z V.10 RS530A 0 0 1 1 1 V.11 V.10 V.11 Z V.10 V.11 Z V.10 RS530 0 1 0 1 1 V.11 V.11 V.11 Z V.11 V.11 Z V.10 X.21 0 1 1 1 1 V.11 V.11 V.11 Z V.11 V.11 Z V.10 V.35 1 0 0 1 1 V.28 V.28 V.28 Z V.28 V.28 Z V.28 RS449/V.36 1 0 1 1 1 V.11 V.11 V.11 Z V.11 V.11 Z V.10 V.28/RS232 1 1 0 1 1 V.28 V.28 V.28 Z V.28 V.28 Z V.28 No Cable 1 1 1 1 1 Z Z Z ZZZZ Z

6

UWW

SWITCHI G TI E WAVEFOR S

LTC1544

B – A

–V

5V

D

0V

V

O

–V

O

A

B

V

O

1.5V 1.5V

t

PLH

50%

90%

10%

t

r

t

SKEW

f = 1MHz : tr ≤ 10ns : tf ≤ 10ns

= V(A) – V(B)

V

DIFF

1/2 V

O

t

PHL

90%

50%

10%

t

f

t

SKEW

1544 F05

Figure 5. V.11, V.35 Driver Propagation Delays

V

OD2

V

OH

R

V

OL

0V

t

PLH

1.5V

f = 1MHz : tr ≤ 10ns : tf ≤ 10ns

INPUT

OUTPUT

0V

t

PHL

1.5V

1544 F06

Figure 6. V.11, V.35 Receiver Propagation Delays

3V

D

0V

V

O

A

–V

O

1.5V

t

PHL

3V

0V

–3V

t

f

1.5V

–3V

t

PLH

0V

3V

t

r

1544 F07

Figure 7. V.10, V.28 Driver Propagation Delays

V

IH

A

V

IL

V

OH

R

V

OL

1.3V

t

PHL

0.8V

1.7V

t

PLH

2.4V

1544 F08

Figure 8. V.10, V.28 Receiver Propagation Delays

7

LTC1544

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APPLICATIONS INFORMATION

Overview

The LTC1543/LTC1544 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.

SERIAL

CONTROLLER

TXD

SCTE

TXC

LTC1543

D1

D2

D3

R1

LTC1344A

103Ω

TXD

SCTE

TXC

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.

DCEDTE

LTC1344A

103Ω

LTC1543

R3

R2

R1

D3

SERIAL

CONTROLLER

TXD

SCTE

TXC

RXC

RXD

RTS

DTR

DCD

DSR

CTS

R2

R3

LTC1544

D1

D2

D3

R1

R2

R3

LL

D4

103Ω

RXC

RXD

RTS

DTR

DCD

DSR

CTS

LL

D2

D1

LTC1544

R3

R2

R1

D3

D2

D1

R4

RXC

RXD

RTS

DTR

DCD

DSR

CTS

LL

8

R4

Figure 9. Complete Multiprotocol Interface in EIA530 Mode

D4

1544 F09

LTC1544

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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. 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

21

LATCH

LTC1344A

DCE/

(DATA)

DTE

M2 M1

22

M0 (DATA)

23 24 1

unconnected (1) or wired to ground (0) in the cable as shown in Figure 10.

The internal pull-up current sources will ensure a binary 1 when a pin is left unconnected and that the LTC1543/ LTC1544 and the LTC1344A enter the no-cable mode when the cable is removed. In the no-cable mode the LTC1543/LTC1544 supply current drops to less than 200µA and all LTC1543/LTC1544 driver outputs and LTC1344A resistive terminations are forced into a high impedance state.

The mode selection may also be accomplished by using jumpers to connect the mode pins to ground or VCC.

CONNECTOR

LTC1543

LTC1544

M0

M1

M2

DCE/DTE

M2

M1

M0

(DATA)

11

12

13

14

13

12

11

NC

Figure 10: Single Port DCE V.35 Mode Selection in the Cable

CABLE

1544 F10

9

LTC1544

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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. 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/LTC1544 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.

The V.10 receiver configuration in the LTC1544 is shown in Figure 13. In V.10 mode switch S3 inside the LTC1544 is turned off.The noninverting input is disconnected inside the LTC1544 receiver and connected to ground. The cable termination is then the 30k input impedance to ground of the LTC1544 V.10 receiver.

I

–3.25mA

Z

–10V

–3V

3V 10V

Figure 12. V.10 Receiver Input Impedance

1544 F12

3.25mA

V

Z

GENERATOR

10

BALANCED

INTERCONNECTING

CABLE

TERMINATION

AA

CC

'

LOAD

CABLE

Figure 11. Typical V.10 Interface

RECEIVER

1544 F11

A

'

R5

R8

20k

6k

S3

R4

B

'

B

C

'

20k

GND

R6 10k

R7 10k

LTC1544

RECEIVER

Figure 13. V.10 Receiver Configuration

1544 F13

LTC1544

U

WUU

APPLICATIONS INFORMATION

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 100Ω. 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.

In V.11 mode, all switches are off except S1 inside the LTC1344A which connects a 103Ω differential termination impedance to the cable as shown in Figure 15.

BALANCED

GENERATOR

INTERCONNECTING

CABLE

TERMINATION

AA'

LOAD

CABLE

RECEIVER

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/LTC1544 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/ LTC1544 receiver and connected to a TTL level reference voltage for a 1.4V receiver trip point.

BALANCED

GENERATOR

INTERCONNECTING

CABLE

TERMINATION

AA

'

LOAD

CABLE

RECEIVER

100Ω

B

C

Figure 14. Typical V.11 Interface

'

A

LTC1344A

R1

51.5Ω

S1

R2

51.5Ω

B

'

C

'

R3

S2

124Ω

R8 6k

S3

B

GND

Figure 15. V.11 Receiver Configuration

B'

C'

R5

20k

R4

20k

MIN

R6 10k

R7 10k

LTC1543 LTC1544

RECEIVER

1544 F14

1544 F15

CC

'

1544 F16

Figure 16. Typical V.28 Interface

'

A

LTC1344A

R1

51.5Ω

S1

R3

S2

124Ω

R2

51.5Ω

B

'

C

'

B

R8 6k

S3

GND

R5

20k

R4

20k

R6 10k

R7 10k

LTC1543 LTC1544

RECEIVER

1544 F17

Figure 17. V.28 Receiver Configuration

11

LTC1544

U

WUU

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. The receiver differential impedance measured at the connector must be

BALANCED

INTERCONNECTING

GENERATOR

50Ω

125Ω

CABLE

A

B

100Ω␣ ±10Ω, and the impedance between shorted terminals (A' and B') and ground C' must be 150Ω ±15Ω.

In V.35 mode, both switches S1 and S2 inside the LTC1344A are on, connecting the T network impedance as shown in Figure 19. The switch in the LTC1543 is 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.

LOAD

CABLE

TERMINATION

A

'

125Ω

B

'

RECEIVER

50Ω

C

'

1544 F18

Figure 18. Typical V.35 Interface

A

'

A

LTC1344A

R1

51.5Ω

S1

R2

51.5Ω

B

'

C

'

R3

S2

124Ω

B

R8 6k

S3

GND

R5

20k

R4

20k

R6 10k

R7 10k

LTC1543

RECEIVER

1544 F19

Figure 19. V.35 Receiver Configuration

12

LTC1544

U

WUU

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.35 DRIVER

124Ω

C1 100pF

S2 ON

51.5Ω

S1 ON

51.5Ω

B

C

1544 F20

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 1µF surface mounted tantalum or ceramic capacitors are required for C1, C2, C3 and C4. The VEE capacitor C5 should be a minimum of

3.3µF. All capacitors are 16V and should be placed as close as possible to the LTC1543 to reduce EMI.

3

V

C3 1µF

C1 1µF

5V

C4 1µF

DD

2

+

C1

LTC1543

1

–

C1

4

V

CC

C2

V

GND

28

+

27

–

26

EE

25

C2 1µF

C5

+

3.3µF

1544 F21

Figure 20. V.35 Driver Using the LTC1344A

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 = 1) 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 200µA.

Figure 21. Charge Pump

Receiver Fail-Safe

All LTC1543/LTC1544 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.

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 and Driver 4/ Receiver 4 in the LTC1544. The INVERT pin in the LTC1544 allows the Driver 4/Receiver 4 enable to be high or low true polarity.

13

LTC1544

U

WUU

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. The interface mode is selected by logic outputs from the controller or from jumpers to either V 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.

CC

Cable-Selectable Multiprotocol Interface

A cable-selectable multiprotocol DTE/DCE interface is shown in Figure 26. The select lines M0, M1 and DCE/DTE are brought out to the connector. The mode is selected by the cable by wiring M0 (connector Pin 18) and M1 (connector Pin 21) and DCE/DTE (connector Pin 25) to ground (connector Pin 7) or letting them float. If M0, M1 or DCE/ DTE is floating, internal pull-up current sources will pull the signals to VCC. The select bit M2 is hard wired to VCC. When the cable is pulled out, the interface will go into the no-cable mode.

Compliance Testing

A European standard EN 45001 test report is available for the LTC1543/LTC1544/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:

Multiprotocol Interface with RL, LL, TM and a DB-25 Connector

If the RL, LL and TM signals are implemented, there are not enough drivers and receivers available in the LTC1543/ LTC1544. In Figure 25, the required control signals are handled by the LTC1544 but the clock/data signals use the LTC1343. The LTC1343 has an additional single-ended driver/receiver pair that can handle two more optional control signals such as TM and LL.

Test Report No. NET2/102201/97. The address of TUV Telecom Services Inc. is: TUV Telecom Services Inc.

Type Approval Division 1775 Old Highway 8, Ste 107 St. Paul, MN 55112 USA Tel. +1 (612) 639-0775 Fax. +1 (612) 639-0873

14

TYPICAL APPLICATIO S

V

CC

5V

3

TXD

SCTE

C3 1µF

1µF

1

C1

C5 1µF

CHARGE

2

PUMP

4

LTC1543

5

D1

6

D2

7

D3

U

LTC1544

C6

100pFC7100pF

3 8 11 12 13

V

CC

28

C2 1µF

27 26

C4

+

3.3µF

25

24 23

22 21

C13 1µF

C12 1µF

2

V

EE

5

C8

100pF

16109764

15 18 17 19 20 22

LTC1344A

LATCH

DCE/DTEM2M1

23 24141

21

M0

2

TXD A (103)

14

TXD B

24

SCTE A (113)

11

SCTE B

C10 1µF

TXC

RXC

RXD

RTS

DTR

DCD

DSR

CTS

V

GND

INVERT

20 19 18 17 16 15

28

EE

27

26 25

24 23

22 21 20 19

18 17

16

15

NC

C11 1µF

8

R1

9

R2

10

R3

11

M0

12

M1

13

M2

14

DCE/DTE

V

CC

C9

1

1µF

LL

10

11 12 13 14

2

3

4

5

6

7

8

9

V

CC

V

DD

D2

LTC1544

M0 M1 M2 DCE/DTE

D1

D3

R1

R2

R3

R4

D4

15 12 17

9 3

16

7

1

4

19 20

23

8

10

6

22

5

13

18

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 A (141)

M2 M1 M0

1544 F22

Figure 22. Controller-Selectable Multiprotocol DTE Port with DB-25 Connector

15

LTC1544

U

TYPICAL APPLICATIO S

V

CC

5V

3

RXD

RXC

C3 1µF

1µF

1

C1

C5 1µF

CHARGE

2

PUMP

4

LTC1543

5

D1

6

D2

7

D3

C6

100pFC7100pF

3 8 11 12 13

V

CC

28

C2 1µF

27 26

C4

+

3.3µF

25

24 23

22 21

C13 1µF

C12 1µF

2

V

EE

5

C8

100pF

16109764

15 18 17 19 20 22

LTC1344A

DCE/DTEM2M1

23 24141

V

CC

LATCH

21

M0

3

RXD A (104)

16

RXD B

17

RXC A (115)

9

RXC B

C10 1µF

TXC

SCTE

TXD

CTS

DSR

DCD

DTR

RTS

R3

V

GND

INVERT

20 19 18 17 16 15

28

EE

27

26 25

24 23

22 21 20 19

18 17

16

15

NC

C11 1µF

8

R1

9

R2

10

R3

11

M0

12

M1

13

M2

14

DCE/DTE

NC

V

CC

C9

1

1µF

LL

V

CC

2

V

DD

3

D1

4

D2

5

D3

LTC1544

6

R1

7

R2

8

10

R4

9

D4

11

M0

12

M1

13

M2

14

NC

DCE/DTE

15

TXC A (114)

12

TXC B

24

SCTE A (113)

11

SCTE B

2

TXD A (103)

14

TXD B

7

SGND (102)

1

SHIELD (101)

5

CTS A (106)

13

CTS B

6

DSR A (107)

22

DSR B

8

DCD A (109)

10

DCD B

20

DTR A (108)

23

DTR B

4

RTS A (105)

19

RTS B

18

LL A (141)

DB-25 FEMALE

CONNECTOR

16

M2 M1 M0

1544 F23

Figure 23. Controller-Selectable DCE Port with DB-25 Connector

TYPICAL APPLICATIO S

V

CC

5V

3

DTE_TXD/DCE_RXD

DTE_SCTE/DCE_RXC

C3 1µF

1µF

1

C1

C5 1µF

CHARGE

2 4

LTC1543

5

D1

6

D2

7

D3

U

PUMP

LTC1544

C6

100pFC7100pF

3 8 11 12 13

V

CC

28

C2 1µF

27 26

C4

+

3.3µF

25

24 23

22 21

C13 1µF

C12 1µF

2

V

EE

5

C8

100pF

16109764

15 18 17 19 20 22

LTC1344A

LATCH

DCE/DTEM2M1

23 24141

M0

21

2

14 24 11

DTE DCE

TXD A

RXD A

TXD B

RXD B

SCTE A

RXC A

SCTE B

RXC B

DTE_TXC/DCE_TXC

DTE_RXC/DCE_SCTE

DTE_RXD/DCE_TXD

C10 1µF

DTE_RTS/DCE_CTS

DTE_DTR/DCE_DSR

DTE_DCD/DCE_DCD

DTE_DSR/DCE_DTR

DTE_CTS/DCE_RTS

DTE_LL/DCE_LL

C9 1µF

10 11 12 13 14

V

10

11 12 13 14

8

9

CC

1 2

3

4

5

6

7

8

9

M0 M1 M2 DCE/DTE

V

CC

V

DD

D1

D2

D3

LTC1544

D4

M0 M1 M2 DCE/DTE

R1

R2

R3

R1

R2

R3

R4

GND

INVERT

20 19 18 17 16 15

28

V

EE

27

26 25

24 23

22 21 20 19

18 17

16

15

NC

C11 1µF

15 12 17

9

16

7

1

4

19 20

23

8

10

6

22

5

13

18

3

TXC A

TXC B RXC A RXC B RXD A RXD B

SG

SHIELD

CONNECTOR

RTS A RTS B DTR A DTR B

DCD A DCD B DSR A DSR B CTS A CTS B

LL A

TXC A TXC B SCTE A SCTE B TXD A TXD B

DB-25

CTS A CTS B DSR A DSR B

DCD A DCD B DTR A DTR B RTS A RTS B

LL A

DCE/DTE

M2 M1 M0

1544 F24

Figure 24. Controller-Selectable Multiprotocol DTE/DCE Port with DB-25 Connector

17

LTC1544

TYPICAL APPLICATIO S

V

CC

5V

1

DTE_LL/DCE_TM

DTE_TXD/DCE_RXD

DTE_SCTE/DCE_RXC

DTE_TXC/DCE_TXC

DTE_RXC/DCE_SCTE

DTE_RXD/DCE_TXD

DTE_TM/DCE_LL

C10 1µF

DTE_RTS/DCE_CTS

DTE_DTR/DCE_DSR

DTE_DCD/DCE_DCD

DTE_DSR/DCE_DTR

DTE_CTS/DCE_RTS

DTE_RL/DCE_RL

DCE/DTE

C3 1µF

LB

C9 1µF

M2 M1 M0

Figure 25. Controller-Selectable Multiprotocol DTE/DCE Port with RL, LL, TM and DB-25 Connector

1µF

2

C1

4 3

C5

8

1µF

5

6

7

9

10 12 13

14

15

16

20

CTRL

22

LATCH

11

INVERT

25

423SET

R1

100k

40

GND

V

CC

1

V

2

V

3

4

5

6

7

8

10

9

11

M0

12

M1

13

M2

14

DCE/DTE

U

LTC1343

CC DD

LTC1544

CHARGE

PUMP

D1

D2

D3

D4

R1

R2

R3

R4

LB

D1

D2

D3

R1

R2

R3

R4

D4

23

GND

INVERT

DCE

V

C6

100pFC7100pF

V

CC

C11 1µF

C13 1µF

C12 1µF

2

V

EE

44

C2 1µF

43 42

C4

+

3.3µF

41

39

38 37 36 35 34 33

32 31 30 29 28 27

26

21 19

M2

18

M1

17

M0

V

CC

24

EC

28

EE

27

26 25 24 23

22 21 20 19

18 17

16

15

NC

C8

100pF

3 8 11 12 13

5

16109764

15 18 17 19 20 22

LTC1344A

LATCH

DCE/DTEM2M1

23 24141

M0

21

18

2

14 24 11

15 12 17

9 3

16

25

7

1

4

19 20 23

8

10

6

22

5

13

21

DTE DCE

LL A

TXD A TXD B SCTE A SCTE B

TXC A TXC B RXC A RXC B RXD A RXD B

TM A LL A

SG

SHIELD

DB-25

CONNECTOR

RTS A RTS B DTR A DTR B

DCD A DCD B DSR A DSR B CTS A CTS B

RL A

1544 F25

TM A

RXD A RXD B RXC A RXC B

TXC A TXC B SCTE A SCTE B TXD A TXD B

CTS A CTS B DSR A DSR B

DCD A DCD B DTR A DTR B RTS A RTS B

RL A

18

TYPICAL APPLICATIO S

LTC1544

U

DTE_TXD/DCE_RXD

DTE_SCTE/DCE_RXC

DTE_TXC/DCE_TXC

DTE_RXC/DCE_SCTE

DTE_RXD/DCE_TXD

C10 1µF

DTE_RTS/DCE_CTS

DTE_DTR/DCE_DSR

DTE_DCD/DCE_DCD

DTE_DSR/DCE_DTR

DTE_CTS/DCE_RTS

C3 1µF

C6

100pFC7100pF

3 8 11 12 13

V

CC

5V

V

CC

C13 1µF

2

V

EE

C12 1µF

C11 1µF

MODE PIN 18 PIN 21

V.35 PIN 7 PIN 7

RS232 PIN 7 NC

5

1µF

C1

C9 1µF

C5 1µF

3

1

CHARGE

2

PUMP

4

LTC1543

5

D1

6

D2

7

D3

8

R1

9

R2

10

R3

11

M0

12

M1

13

M2

NC

14

DCE/DTE

V

CC

1

V

CC

2

V

DD

3

D1

4

D2

5

D3

LTC1544

6

R1

7

R2

8

R3

10

R4

9

D4

11

M0

12

M1

13

NC

M2

14

DCE/DTE

GND

INVERT

28

C2 1µF

27 26

C4

+

3.3µF

25

24 23

22 21

20 19 18 17 16 15

28

V

EE

27

26

25 24 23

22 21 20 19

18 17

16

CABLE WIRING FOR MODE SELECTION

RS449, V.36 NC PIN 7

15

NC

C8

100pF

CABLE WIRING FOR DTE/DCE SELECTION

MODE PIN 25

DTE PIN 7 DCE NC

16109764

15 18 17 19 20 22

LTC1344A

LATCH

DCE/DTEM2M1

23 24141

V

CC

21

M0

DTE

TXD A TXD B SCTE A SCTE B

TXC A TXC B RXC A RXC B RXD A RXD B SG

SHIELD

DB-25

CONNECTOR

DCE/DTE M1 M0

RTS A RTS B DTR A DTR B

DCD A DCD B DSR A DSR B CTS A CTS B

DCE

RXD A RXD B RXC A RXC B

TXC A TXC B

SCTE A SCTE B TXD A TXD B

CTS A CTS B DSR A DSR B

DCD A DCD B DTR A DTR B RTS A RTS B

2

14 24 11

15 12 17

9

3

16

7

1

25 21 18

4

19 20

23

8

10

6

22

5

13

Figure 26. Cable-Selectable Multiprotocol DTE/DCE Port with 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.

1544 F26

19

LTC1544

PACKAGE DESCRIPTIO

5.20 – 5.38** (0.205 – 0.212)

U

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)

2526 22 21 20 19 181716 1523242728

12345678 9 10 11 12 1413

7.65 – 7.90

(0.301 – 0.311)

1.73 – 1.99

(0.068 – 0.078)

° – 8°

0

0.13 – 0.22

(0.005 – 0.009)

NOTE: DIMENSIONS ARE IN MILLIMETERS

*

DIMENSIONS DO NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.152mm (0.006") PER SIDE

**

DIMENSIONS DO NOT INCLUDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED 0.254mm (0.010") PER SIDE

0.55 – 0.95

(0.022 – 0.037)

0.65

(0.0256)

BSC

0.25 – 0.38

(0.010 – 0.015)

0.05 – 0.21

(0.002 – 0.008)

G28 SSOP 1098

RELATED PARTS

PART NUMBER DESCRIPTION COMMENTS

LTC1321 Dual RS232/RS485 Transceiver Two RS232 Driver/Receiver Pairs or Two RS485 Driver/Receiver Pairs LTC1334 Single 5V RS232/RS485 Multiprotocol Transceiver Two RS232 Driver/Receiver or Four RS232 Driver/Receiver Pairs LTC1343 Software-Selectable Multiprotocol Transceiver 4-Driver/4-Receiver for Data and Clock Signals LTC1344A Software-Selectable Cable Terminator Perfect for Terminating the LTC1543 LTC1345 Single Supply V.35 Transceiver 3-Driver/3-Receiver for Data and Clock Signals LTC1346A Dual Supply V.35 Transceiver 3-Driver/3-Receiver for Data and Clock Signals LTC1543 Software-Selectable Multiprotocol Transceiver Companion to LTC1544 for Data and Clock Signals LTC1546 Multiprotocol Transceiver with Termination Companion to LTC1544 for Data and Clock Signals

20

Linear Technology Corporation

1630 McCarthy Blvd., Milpitas, CA 95035-7417

(408) 432-1900 ● FAX: (408) 434-0507

●

www.linear-tech.com

1544fa LT/TP 0100 2K REV A • PRINTED IN USA

 LINEAR TECHNOLOGY CORPORATION 1998