LINER LTC1545IG

LTC1545
Software-Selectable
Multiprotocol Transceiver
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FEATURES
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DESCRIPTIO
The LTC®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.
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
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APPLICATIO S
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Data Networking
CSU and DSU
Data Routers
, LTC and LT are registered trademarks of Linear Technology Corporation.
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TYPICAL APPLICATIO
DTE or DCE Multiprotocol Serial Interface with DB-25 Connector
RL
TM
RI
LL
CTS
DSR
DCD
DTR
RTS
D2
D1
RXD
TXC
RXC
D4
R5
R4
D3
R3
R2
TXD
D2
D1
LTC1543
LTC1545
D5
SCTE
D3
R3
R1
R2
R1
LTC1344A
21
25
*
18 13 5
10 8
22 6
23 20 19 4
1
16 3
9
17
12 15 11 24 14
2
TXD A (103)
TXD B
SCTE A (113)
TXC A (114)
SCTE B
TXC B
RXC A (115)
RXC B
RXD A (104)
RXD B
SG (102)
SHIELD (101)
RTS A (105)
RTS B
DTR A (108)
DCD A (107)
DTR B
DCD B
DSR A (109)
CTS A (106)
DSR B
LL A (141)
CTS B
RI A (125)
TM A (142)
RL A (140)
DB-25 CONNECTOR
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*OPTIONAL
1545 TA01
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LTC1545
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ABSOLUTE MAXIMUM RATINGS
PACKAGE/ORDER INFORMATION
(Note 1)
Supply Voltage
VCC ..................................................................... 6.5V
VEE ........................................................ – 10V to 0.3V
VDD ....................................................... – 0.3V to 10V
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)
Short-Circuit Duration
Transmitter Output ..................................... Indefinite
Receiver Output .......................................... Indefinite
VEE .................................................................. 30 sec
Operating Temperature Range
LTC1545C .............................................. 0°C to 70°C
LTC1545I ........................................... – 40°C to 85°C
Storage Temperature Range ................ – 65°C to 150°C
Lead Temperature (Soldering, 10 sec)................. 300°C
TOP VIEW
ORDER PART
NUMBER
VCC
1
36 VEE
VDD
2
35 GND
D1
3
D2
4
D3
5
R1
6
R2
7
R3
8
D4
9
34 D1 A
D1
33 D1 B
32 D2 A
D2
31 D2 B
D3
LTC1545CG
LTC1545IG
30 D3/R1 A
29 D3/R1 B
28 R2 A
R1
27 R2 B
R4 10
R2
M0 11
M1 12
26 R3 A
25 R3 B
R3
24 D4 A
M2 13
D4
DCE/DTE 14
23 R4 A
R4
D4ENB 15
22 R5 A
21 D5 A
R4EN 16
R5
R5 17
D5 18
20 VDD
19 VCC
D5
G PACKAGE
36-LEAD PLASTIC SSOP
TJMAX = 150°C, θJA = 65°C/ W
Consult factory for Military grade parts.
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
ICC
VCC Supply Current (DCE Mode,
All Digital Pins = GND or VCC)
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
IEE
VEE Supply Current (DCE Mode,
All Digital Pins = GND or VCC)
IDD
PD
MIN
TYP
MAX
UNITS
●
●
●
●
●
2.7
110
1
1
10
5
150
3
3
500
mA
mA
mA
mA
µA
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
●
●
●
●
●
●
2.0
23
34
1
12
10
4.0
35
50
3
18
500
mA
mA
mA
mA
mA
µA
VDD Supply Current (DCE Mode,
All Digital Pins = GND or VCC)
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
●
●
●
●
●
0.3
0.3
1
13.5
10
2
2
3
18
500
mA
mA
mA
mA
µA
Internal Power Dissipation (DCE Mode,
(All Digital Pins = GND or VCC)
RS530, RS530-A, X.21 Modes, Full Load
V.28 Mode, Full Load
Supplies
2
340
64
mW
mW
LTC1545
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
●
0.8
V
D1, D2, D3, D4, D5
M0, M1, M2, DCE, D4ENB, R4EN = GND (LTC1545C)
M0, M1, M2, DCE, D4ENB, R4EN = GND (LTC1545I)
M0, M1, M2, DCE, D4ENB, R4EN = VCC
●
●
●
●
– 100
– 120
– 50
– 50
±10
– 30
– 30
±10
µA
µA
µA
µA
3
4.5
VOH
Output High Voltage
IO = – 4mA
●
VOL
Output Low Voltage
IO = 4mA
●
IOSR
Output Short-Circuit Current
0V ≤ VO ≤ VCC
●
IOZR
Three-State Output Current
M0 = M1 = M2 = VCC, 0V ≤ VO ≤ VCC
– 50
V
0.3
0.8
V
40
50
mA
±1
µA
V.11 Driver
VODO
Open Circuit Differential Output Voltage
RL = 1.95k (Figure 1)
●
VODL
Loaded Differential Output Voltage
RL = 50Ω (Figure 1)
RL = 50Ω (Figure 1)
●
±5
0.5VODO
±2
V
0.67VODO
V
∆VOD
Change in Magnitude of Differential
Output Voltage
RL = 50Ω (Figure 1)
●
0.2
V
VOC
Common Mode Output Voltage
RL = 50Ω (Figure 1)
●
3
V
∆VOC
Change in Magnitude of Common Mode
Output Voltage
RL = 50Ω (Figure 1)
●
0.2
V
ISS
Short-Circuit Current
VOUT = GND
IOZ
Output Leakage Current
– 0.25V ≤ VO ≤ 0.25V, Power Off or
No-Cable Mode or Driver Disabled
●
t r, t f
Rise or Fall Time
LTC1545C (Figures 2, 5)
LTC1545I (Figures 2, 5)
●
●
t PLH
Input to Output
LTC1545C (Figures 2, 5)
LTC1545I (Figures 2, 5)
t PHL
Input to Output
∆t
t SKEW
±150
mA
±1
±100
µA
2
2
15
15
25
35
ns
ns
●
●
20
20
40
40
65
75
ns
ns
LTC1545C (Figures 2, 5)
LTC1545I (Figures 2, 5)
●
●
20
20
40
40
65
75
ns
ns
Input to Output Difference, tPLH – tPHL
LTC1545C (Figures 2, 5)
LTC1545I (Figures 2, 5)
●
●
0
0
3
3
12
17
ns
ns
Output to Output Skew
(Figures 2, 5)
3
ns
V.11 Receiver
VTH
Input Threshold Voltage
– 7V ≤ VCM ≤ 7V
●
∆VTH
Input Hysteresis
– 7V ≤ VCM ≤ 7V
●
IIN
Input Current (A, B)
– 10V ≤ VA,B ≤ 10V
●
RIN
Input Impedance
– 10V ≤ VA,B ≤ 10V
●
t r, t f
Rise or Fall Time
(Figures 2, 6)
t PLH
Input to Output
LTC1545C (Figures 2, 6)
LTC1545I (Figures 2, 6)
●
●
50
50
80
90
ns
ns
t PHL
Input to Output
LTC1545C (Figures 2, 6)
LTC1545I (Figures 2, 6)
●
●
50
50
80
90
ns
ns
∆t
Input to Output Difference, tPLH – tPHL
LTC1545C (Figures 2, 6)
LTC1545I (Figures 2, 6)
●
●
4
4
16
21
ns
ns
– 0.2
15
15
0
0
0.2
V
40
mV
±0.66
mA
30
kΩ
15
ns
3
LTC1545
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
●
±4
VT
Output Voltage
RL = 450Ω (Figure 3)
RL = 450Ω (Figure 3)
●
±3.6
0.9VO
ISS
Short-Circuit Current
VO = GND
IOZ
Output Leakage Current
– 0.25V ≤ VO ≤ 0.25V, Power Off or
No-Cable Mode or Driver Disabled
t r, t f
Rise or Fall Time
RL = 450Ω, CL = 100pF (Figures 3, 7)
2
µs
t PLH
Input to Output
RL = 450Ω, CL = 100pF (Figures 3, 7)
1
µs
t PHL
Input to Output
RL = 450Ω, CL = 100pF (Figures 3, 7)
1
µs
V.10 Driver
±6
V
±0.1
●
V
±150
mA
±100
µA
V.10 Receiver
VTH
Receiver Input Threshold Voltage
∆VTH
Receiver Input Hysteresis
IIN
Receiver Input Current
– 10V ≤ VA ≤ 10V
●
RIN
Receiver Input Impedance
– 10V ≤ VA ≤ 10V
●
t r , tf
Rise or Fall Time
tPLH
Input to Output
tPHL
∆t
●
– 0.25
0.25
25
●
15
V
50
mV
±0.66
mA
30
kΩ
(Figures 4, 8)
15
ns
(Figures 4, 8)
55
ns
Input to Output
(Figures 4, 8)
109
ns
Input to Output Difference, tPLH – tPHL
(Figures 4, 8)
60
ns
VO
Output Voltage
Open Circuit
RL = 3k (Figure 3)
●
●
ISS
Short-Circuit Current
VO = GND
●
IOZ
Output Leakage Current
– 0.25V ≤ VO ≤ 0.25V, Power Off or
No-Cable Mode or Driver Disabled
●
SR
Slew Rate
RL = 3k, CL = 2500pF (Figures 3, 7)
●
t PLH
Input to Output
RL = 3k, CL = 2500pF (Figures 3, 7)
●
t PHL
Input to Output
RL = 3k, CL = 2500pF (Figures 3, 7)
V.28 Driver
±5
±8.5
±1
4
±10
V
V
±150
mA
±100
µA
30
V/µs
1.3
2.5
µs
●
1.3
2.5
µs
1.5
0.8
V
0.1
0.3
V
5
7
V.28 Receiver
VTHL
Input Low Threshold Voltage
●
VTLH
Input High Threshold Voltage
●
∆VTH
Receiver Input Hysterisis
●
RIN
Receiver Input Impedance
– 15V ≤ VA ≤ 15V
t r , tf
Rise or Fall Time
(Figures 4, 8)
tPLH
Input to Output
(Figures 4, 8)
●
60
100
ns
tPHL
Input to Output
(Figures 4, 8)
●
150
450
ns
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.
4
●
2
3
1.6
V
15
kΩ
ns
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 = 25°C.
LTC1545
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PIN FUNCTIONS
VCC (Pins 1, 19): Positive Supply for the Transceivers.
4.75V ≤ VCC ≤ 5.25V. Connect a 1µF 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 1µF
capacitor to ground.
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.
D1 (Pin 3): TTL Level Driver 1 Input.
R4 A (Pin 23): Receiver 4 Input.
D2 (Pin 4): TTL Level Driver 2 Input.
D4 A (Pin 24): Driver 4 Input.
D3 (Pin 5): TTL Level Driver 3 Input.
R3 B (Pin 25): Receiver 3 Noninverting Input.
R1 (Pin 6): CMOS Level Receiver 1 Output.
R3 A (Pin 26): Receiver 3 Inverting Input.
R2 (Pin 7): CMOS Level Receiver 2 Output.
R2 B (Pin 27): Receiver 2 Noninverting Input.
R3 (Pin 8): CMOS Level Receiver 3 Output.
R2 A (Pin 28): Receiver 2 Inverting Input.
D4 (Pin 9): TTL Level Driver 4 Input.
D3/R1 B (Pin 29): Receiver 1 Noninverting Input and
Driver 3 Noninverting Output.
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.
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.
M2 (Pin 13): TTL Level Mode Select Input 2 with Pull-Up
to VCC.
D1 B (Pin 33): Driver 1 Noninverting Output.
DCE/DTE (Pin 14): TTL Level Mode Select Input with
Pull-Up to VCC. Logic high enables Driver 3. Logic low
enables Receiver 1.
GND (Pin 35): Ground.
D4ENB (Pin 15): TTL Level Enable Input with Pull-Up to
VCC. Logic low enables Driver 4.
D1 A (Pin 34): Driver 1 Inverting Output.
VEE (Pin 36): Negative Supply Voltage. Connect to VEE Pin
26 on LTC1543. Connect a 1µF capacitor to ground.
R4EN (Pin 16): TTL Level Enable Input with Pull-Up to VCC.
Logic high enables Receiver 4.
TEST CIRCUITS
A
B
RL
A
VOD
RL
RL
100Ω
CL
100pF
B
CL
100pF
A
R
15pF
VOC
1545 F02
B
1545 F01
Figure 1. V.11 Driver Test Circuit
Figure 2. V.11 Driver/Receiver AC Test Circuit
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LTC1545
TEST CIRCUITS
D
D
A
A
A
R
15pF
RL
CL
1545 F04
1545 F03
Figure 3. V.10/V.28 Driver Test Circuit
Figure 4. V.10/V.28 Receiver Test Circuit
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ODE SELECTIO
LTC1545 MODE NAME
M2
M1
M0
D1
D2
(Note 1) (Note 2)
D3
D4
D5
(Note 1)
R1
R2
R3
(Note 3)
R4
R5
Not Used (Default V.11)
0
0
0
V.11
V.11
V.11
V.10
V.10
V.11
V.11
V.11
V.10
V.10
RS530A
0
0
1
V.11
V.10
V.11
V.10
V.10
V.11
V.10
V.11
V.10
V.10
RS530
0
1
0
V.11
V.11
V.11
V.10
V.10
V.11
V.11
V.11
V.10
V.10
X.21
0
1
1
V.11
V.11
V.11
V.10
V.10
V.11
V.11
V.11
V.10
V.10
V.35
1
0
0
V.28
V.28
V.28
V.28
V.28
V.28
V.28
V.28
V.28
V.28
RS449/V.36
1
0
1
V.11
V.11
V.11
V.10
V.10
V.11
V.11
V.11
V.10
V.10
V.28/RS232
1
1
0
V.28
V.28
V.28
V.28
V.28
V.28
V.28
V.28
V.28
V.28
D4ENB = 1, R4EN = 0
M0 = M1 = M2 = 1
1
1
1
Z
Z
Z
Z
Z
Z
Z
Z
Z
Z
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.
Note 2: Driver 4 is enabled by D4ENB = 0 (Pin 15).
Note 3: Receiver 4 is enabled by R4EN = 1 (Pin 16).
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SWITCHI G TI E WAVEFOR S
5V
f = 1MHz : t r ≤ 10ns : t f ≤ 10ns
1.5V
D
0V
t PHL
t PLH
VO
B–A
–VO
1.5V
90%
50%
VDIFF = V(B) – V(A)
10%
1/2 VO
tr
90%
50%
10%
tf
A
VO
B
t SKEW
Figure 5. V.11 Driver Propagation Delays
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t SKEW
1545 F05
LTC1545
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SWITCHI G TI E WAVEFOR S
VOD2
B–A
–VOD2
f = 1MHz : t r ≤ 10ns : t f ≤ 10ns
0V
INPUT
t PLH
VOH
R
VOL
0V
t PHL
OUTPUT
1.5V
1.5V
1545 F06
Figure 6. V.11 Receiver Propagation Delays
3V
1.5V
1.5V
D
0V
t PHL
VO
t PLH
3V
3V
0V
A
0V
–3V
–VO
1545 F07
–3V
tf
tr
Figure 7. V.10, V.28 Driver Propagation Delays
VIH
1.5V
1.5V
A
VIL
t PHL
VOH
R
VOL
t PLH
1.5V
1.5V
1545 F08
Figure 8. V.10, V.28 Receiver Propagation Delays
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APPLICATIONS INFORMATION
Overview
Mode Selection
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.
The interface protocol is selected using the mode select
pins M0, M1 and M2 (see the Mode Selection table).
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.
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.
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LTC1545
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APPLICATIONS INFORMATION
DTE
SERIAL
CONTROLLER
LTC1543
DCE
LTC1344A
LTC1344A
LTC1543
SERIAL
CONTROLLER
TXD
D1
TXD
103Ω
R3
TXD
SCTE
D2
SCTE
103Ω
R2
SCTE
R1
D3
TXC
R1
103Ω
TXC
D3
TXC
RXC
R2
103Ω
RXC
D2
RXC
RXD
R3
103Ω
RXD
D1
RXD
LTC1545
LTC1545
RTS
D1
RTS
R3
RTS
DTR
D2
DTR
R2
DTR
D3
R1
DCD
R1
DCD
D3
DCD
DSR
R2
DSR
D2
DSR
CTS
R3
CTS
D1
CTS
LL
TM
RI
RL
LL
D4
R4
TM
R4
R5
D5
D4
RI
D5
RL
R5
LL
TM
RI
RL
1545 F09
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
200µA and all LTC1543/LTC1545 driver outputs and
LTC1344A resistive terminations are forced into a high
impedance state.
8
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 required the user to
change termination modules every time the interface
standard has changed. Custom cables have been used
LTC1545
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APPLICATIONS INFORMATION
LATCH
21
LTC1344A
DCE/
DTE M2
22
23
M1 M0 (DATA)
24
1
CONNECTOR
(DATA)
M0
LTC1543
M1
M2
DCE/DTE
DCE/DTE
M2
M1
LTC1545
M0
D4ENB
R4EN
11
12
13
NC
14
NC
14
CABLE
VCC
13
12
11
15
10k
16
(DATA)
1545 F10
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.
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.
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.11 (RS422) Interface
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.
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.
9
LTC1545
U
U
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APPLICATIONS INFORMATION
BALANCED
INTERCONNECTING
CABLE
GENERATOR
GENERATOR
LOAD
CABLE
TERMINATION
C'
C
LOAD
CABLE
TERMINATION
RECEIVER
A'
A
BALANCED
INTERCONNECTING
CABLE
1545 F11
Figure 11. Typical V.10 Interface
A
A'
B
B'
C
C'
RECEIVER
100Ω
MIN
1545 F14
Figure 14. Typical V.11 Interface
A'
A
IZ
3.25mA
R1
51.5Ω
LTC1344A
R8
6k
LTC1543
LTC1545
R5
20k
R6
10k
S1
S2
–10V
–3V
3V
10V
R3
124Ω
R2
51.5Ω
VZ
RECEIVER
S3
R4
20k
B
R7
10k
B'
GND
C'
1545 F15
Figure 15. V.11 Receiver Configuration
1545 F12
–3.25mA
Figure 12. V.10 Receiver Input Impedance
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.
V.28 (RS232) Interface
A'
A
LTC1545
R8
6k
R5
20k
R6
10k
S3
B'
C'
R4
20k
B
GND
RECEIVER
R7
10k
1545 F13
Figure 13. V.10 Receiver Configuration
10
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
U
U
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APPLICATIONS INFORMATION
BALANCED
INTERCONNECTING
CABLE
GENERATOR
LOAD
CABLE
TERMINATION
RECEIVER
A'
A
C'
C
1545 F16
Figure 16. Typical V.28 Interface
A'
A
R1
51.5Ω
LTC1344A
S1
R8
6k
R3
124Ω
S2
R2
51.5Ω
R6
10k
S3
R4
20k
B
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 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.
LTC1543
LTC1545
R5
20k
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
100Ω␣ ±10Ω, and the impedance between shorted terminals (A' and B') and ground C' must be 150Ω ±15Ω.
RECEIVER
R7
10k
B'
A'
GND
C'
A
1545 F17
R1
51.5Ω
Figure 17. V.28 Receiver Configuration
S2
GENERATOR
A
50Ω
RECEIVER
125Ω
125Ω
50Ω
50Ω
R7
10k
R4
20k
B
B'
1545 F19
GND
C'
A'
RECEIVER
S3
R3
124Ω
R2
51.5Ω
LOAD
CABLE
TERMINATION
R8
6k
R5
20k
R6
10k
S1
BALANCED
INTERCONNECTING
CABLE
LTC1543
LTC1344A
Figure 19. V.35 Receiver Configuration
50Ω
B
B'
C
C'
A
LTC1344A
51.5Ω
1545 F18
Figure 18. Typical V.35 Interface
V.35 DRIVER
124Ω
S2
ON
S1
ON
51.5Ω
V.35 Interface
B
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
C
1545 F20
Figure 20. V.35 Driver Using the LTC1344A
11
LTC1545
U
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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 200µA.
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. The turn-on
time for the charge pump is 60ms.
3
C3
1µF
2
C1
1µF 1
4
5V
VDD
C2 +
28
+
–
27
C1
C2
C2
1µF
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, 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:
LTC1543
C1–
VCC
VEE
GND
26
25
+
C5
3.3µF
C4
1µF
1545 F21
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
DTE vs DCE Operation
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
U
TYPICAL APPLICATIONS
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
VCC
5V
RTS
DTR
R2
10
RXD
C10
1µF
R1
9
RXC
C9
1µF
R3
CTS
LL
RI
TM
RL
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
36
C11
1µF
35
34
4
33
19
32
20
31
23
RTS A (105)
RTS B
DTR A (108)
DTR B
D3
6
R1
7
R2
8
R3
9
D4
10
R4
17
R5
18
14
2
23
DCE/DTE
4
13
24
M2
3
12
16 15 18 17 19 20 22 23 24 1
M1
1,19
VCC
2,20
VDD
11
9 10
7
LTC1545
DSR
5 4 6 7
M0
5
DCD
VEE
C12
1µF
D3
8
TXC
2
C4
3.3µF
M0
CHARGE
PUMP
2
21
C2
1µF
26
M1
27
LATCH
M2
1
VCC
DCE/DTE
C1
1µF
28
+
C3
1µF
3
C13
1µF
D5
M0
D4ENB
M1
M2
R4EN
30
8
29
10
28
6
27
22
26
5
25
13
24
18
23
*
22
25
21
21
DCD A (109)
DCD B
DSR A (107)
DSR B
CTS A (106)
CTS B
LL (141)
RI (125)
TM (142)
RL (140)
15
16
NC
DCE/DTE
M0
M1
M2
*OPTIONAL
1544 F22
Figure 22. Controller-Selectable Multiprotocol DTE Port with DB-25 Connector
13
LTC1545
U
TYPICAL APPLICATIONS
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
VCC
5V
C10
1µF
R1
9
SCTE
C9
1µF
14
R3
VEE
GND
D1
D2
R1
R2
R3
R4
17
R5
18
11
12
13
NC
14
9
20
15
19
12
18
24
17
11
16
2
15
14
RXC A (115)
RXC B
TXC A (114)
TXC B
SCTE A (113)
SCTE B
TXD A (103)
TXD B
SGND (102)
SHIELD (101)
36
C11
1µF
35
34
5
33
13
32
6
31
22
30
8
29
10
28
20
27
23
CTS A (106)
CTS B
DSR A (107)
DSR B
D5
M0
D4ENB
M1
M2
R4EN
DCD A (109)
DCD B
DTR A (108)
DTR B
4 RTS A (105)
19 RTS B
24
*
23
18
22
21
21
25
RI (125)
LL (141)
RL (140)
TM (142)
15
16
NC
DCE/DTE
M0
M1
M2
*OPTIONAL
1544 F23
Figure 23. Controller-Selectable DCE Port with DB-25 Connector
14
RXD B
DB-25 FEMALE
CONNECTOR
25
D4
10
RL
21
26
9
TM
17
RXD A (104)
D3
8
LL
22
1
1,19
VCC
2,20
VDD
7
RI
16
7
LTC1545
RTS
3
23
DCE/DTE
6
DTR
VCC
M2
5
DCD
16 15 18 17 19 20 22 23 24 1
M1
4
DSR
9 10
M0
3
CTS
5 4 6 7
D3
8
TXC
VEE
C12
1µF
24
D1
6
2
C4
3.3µF
M0
CHARGE
PUMP
2
21
C2
1µF
M1
27
26
LATCH
VCC
M2
1
C13
1µF
DCE/DTE
C1
1µF
28
+
C3
1µF
3
LTC1545
U
TYPICAL APPLICATIONS
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
D1
6
DTE_SCTE/DCE_RXC
D2
7
R1
9
DTE_RXC/DCE_SCTE
R2
10
DTE_RXD/DCE_TXD
11
12
VEE
C12
1µF
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
M1
13
M2
14
DCE/DTE
C10
1µF
DTE_RTS/DCE_CTS
DTE_DTR/DCE_DSR
VCC
5V
C9
1µF
1,19
VCC
2,20
VDD
3
1
VEE
GND
D1
4
D2
5
DTE_DSR/DCE_DTR
DTE_CTS/DCE_RTS
DTE_LL/DCE_RI
DTE_RI/DCE_LL
DTE_TM/DCE_RL
DTE_RL/DCE_TM
6
R1
7
R2
8
R3
9
D4
10
R4
17
R5
18
11
12
13
14
DCE
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
SG
SHIELD
DB-25
CONNECTOR
36
C11
1µF
35
34
4
33
19
32
20
31
23
RTS A
CTS A
RTS B
CTS B
DTR A
DSR A
DTR B
DSR B
DCD A
DCD A
D3
LTC1545
DTE_DCD/DCE_DCD
DTE
TXD A
D3
8
DTE_TXC/DCE_TXC
2
C4
3.3µF
M0
CHARGE
PUMP
2
21
C2
1µF
M1
27
26
M2
1
LATCH
VCC
DCE/DTE
C1
1µF
28
+
C3
1µF
3
C13
1µF
D5
M0
D4ENB
M1
M2
R4EN
30
8
29
10
28
6
27
22
26
5
25
13
24
18
23
*
22
25
21
21
DCD B
DCD B
DSR A
DTR A
DSR B
DTR B
CTS A
RTS A
CTS B
RTS B
LL
RI
RI
LL
TM
RL
RL
TM
15
16
NC
DCE/DTE
DCE/DTE
M0
M1
M2
*OPTIONAL
1544 F24
Figure 24. Controller-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.
15
LTC1545
U
PACKAGE DESCRIPTION
Dimensions in inches (millimeters) unless otherwise noted.
G Package
36-Lead Plastic SSOP (0.209)
(LTC DWG # 05-08-1640)
12.67 – 12.93*
(0.499 – 0.509)
36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 20 19
7.65 – 7.90
(0.301 – 0.311)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
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)
0.65
(0.0256)
BSC
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
0.05 – 0.21
(0.002 – 0.008)
0.25 – 0.38
(0.010 – 0.015)
G36 SSOP 1098
RELATED PARTS
PART NUMBER
DESCRIPTION
LTC1321
Dual RS232/RS485 Transceiver
Two RS232 Driver/Receiver Pairs or Two RS485 Driver/Receiver Pairs
LTC1322
Dual RS232/RS485 Transceiver
Four RS232 Driver/Receiver Pairs or Two RS485 Driver/Receiver Pairs
LTC1334
Single 5V RS232/RS485 Multiprotocol Transceiver
Two RS232 Driver/Receiver Pairs or Four RS232 Driver/Receiver Pairs
LTC1335
Dual RS232/RS485 Transceiver
Four RS232 Driver/Receiver Pairs or Two RS485 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/LTC1545 for Data and Clock Signals
LTC1544
Software-Selectable Multiprotocol Transceiver
4-Driver/4-Receiver for Control Signals
LTC1387
Single 5V RS232/RS485 Multiprotocol Transceiver
Two RS232 Driver/Receiver Pairs or One RS485 Driver/Receiver Pair
16
Linear Technology Corporation
COMMENTS
1545fa LT/TP 1199 2K REV A • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408)432-1900 ● FAX: (408) 434-0507 ● www.linear-tech.com
 LINEAR TECHNOLOGY CORPORATION 1998