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1
LTC1345
Single Supply
V.35 Transceiver
s
Single Chip Provides All V.35 Differential Clock
and Data Signals
s
Operates From Single 5V Supply
s
Software Selectable DTE or DCE Configuration
s
Transmitters and Receivers Will Withstand
Repeated
10kV ESD Pulses
s
Shutdown Mode Reduces I
CC
to 1
A Typ
s
10MBaud Transmission Rate
s
Transmitter Maintains High Impedance When
Disabled, Shut Down, or with Power Off
s
Meets CCITT V.35 Specification
s
Transmitters are Short-Circuit Protected
The LTC
1345 is a single chip transceiver that provides the
differential clock and data signals for a V.35 interface from
a single 5V supply. Combined with an external resistor
termination network and an LT
1134A RS232 transceiver
for the control signals, the LTC1345 forms a complete low
power DTE or DCE V.35 interface port operating from a
single 5V supply.
The LTC1345 features three current output differential
transmitters, three differential receivers, and a charge
pump. The transceiver can be configured for DTE or DCE
operation or shut down using two Select pins. In the
Shutdown mode, the supply current is reduced to 1
A.
The transceiver operates up to 10Mbaud. All transmitters
feature short-circuit protection and a Receiver Output
Enable pin allows the receiver outputs to be forced into a
high impedance state. Both transmitter outputs and re-
ceiver inputs feature
10kV ESD protection. The charge
pump features a regulated V
EE
output using three external
1
F capacitors.
s
Modems
s
Telecommunications
s
Data Routers
Clock and Data Signals for V.35 Interface
DCE
DTE
, LTC and LT are registered trademarks of Linear Technology Corporation.
4
1
F
V
CC1
5V
2
1
1
F
1
F
1
F
1
F
28
27
3
6
1
2
26
25
12
12
11
18
17
1
F
DX
LTC1345
LTC1345
BI
627T500/1250
BI
627T500/1250
BI TECHNOLOGIES
627T500/1250 (SOIC) OR
899TR50/125 (DIP)
28
V
CC2
5V
1
2
1
F
4
3
27
1
F
RX
T
TXD (103)
SCTE (113)
TXC (114)
RXC (115)
RXD (104)
GND (102)
T
7
3
4
24
23
10
13
9
16
15
DX
RX
T
T
11
14
13
20
19
1
6
2
26
25
T
T
12
12
11
18
17
10
14
8
9
3
7
4
24
23
T
T
8
13
10
9
16
15
7
5
5
7
5
8
6
22
21
T
T
RX
RX
RX
V
CC1
10
14
LTC1345 TA01
9
V
CC2
DX
DX
DX
50
=
125
T
50
FEATURES
DESCRIPTIO
U
APPLICATIO S
U
TYPICAL APPLICATIO
U
2
LTC1345
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
V
OD
Transmitter Differential Output Voltage
Figure 1, 4V
V
OS
4V
q
0.44
0.55
0.66
V
V
OC
Transmitter Common-Mode Output Voltage
Figure 1, V
OS
= 0V
q
0.6
0
0.6
V
I
OH
Transmitter Output High Current
V
Y, Z
= 0V
q
12.6
11
9.4
mA
I
OL
Transmitter Output Low Current
V
Y, Z
= 0V
q
9.4
11
12.6
mA
I
OZ
Transmitter Output Leakage Current
S1 = S2 = 0V, 5V
V
Y, Z
5V
q
1
100
A
R
O
Transmitter Output Impedance
2V
V
Y, Z
2V
100
k
V
TH
Differential Receiver Input Threshold Voltage
7V
(V
A
+ V
B
)/2
7V
q
25
200
mV
V
TH
Receiver Input Hysterisis
7V
(V
A
+ V
B
)/2
7V
50
mV
I
IN
Receiver Input Current (A, B)
7V
V
A, B
7V
q
0.4
mA
R
IN
Receiver Input Impedance
7V
V
A, B
7V
q
17.5
30
k
V
OH
Receiver Output High Voltage
I
O
= 4mA, V
B, A
= 0.2V
q
3
4.5
V
V
OL
Receiver Output Low Voltage
I
O
= 4mA, V
B, A
= 0.2V
q
0.2
0.4
V
I
OSR
Receiver Output Short-Circuit Current
0V
V
O
V
CC
q
7
85
mA
I
OZR
Receiver Three-State Output Current
S1 = S2 = 0V, 0V
V
O
V
CC
q
10
A
V
IH
Logic Input High Voltage
T, S1, S2, OE
q
2
V
V
IL
Logic Input Low Voltage
T, S1, S2, OE
q
0.8
V
I
IN
Logic Input Current
T, S1, S2, OE
q
10
A
I
CC
V
CC
Supply Current
Figure 1, V
OS
= 0, S1 = S2 = HIGH
q
118
170
mA
No Load, S1 = S2 = HIGH
q
19
30
mA
Shutdown, S1 = S2 = 0V
q
1
100
A
V
EE
V
EE
Voltage
No Load, S1 = S2 = HIGH
5.5
V
ORDER PART
NUMBER
THREE V.35 TRANSMITTERS AND THREE RECEIVERS
T
JMAX
= 125
C,
JA
= 56
C/W (NW)
T
JMAX
= 125
C,
JA
= 65
C/W (SW)
Consult factory for Military grade parts.
The
q
denotes specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25
C. V
CC
= 5V
5% (Notes 2, 3), unless otherwise specified.
(Note 1)
Supply Voltage, V
CC
.................................................. 6V
Input Voltage
Transmitters ........................... 0.3V to (V
CC
+ 0.3V)
Receivers ............................................... 18V to 18V
S1, S2, OE ............................... 0.3V to (V
CC
+ 0.3V)
Output Voltage
Transmitters .......................................... 18V to 18V
Receivers ................................ 0.3V to (V
CC
+ 0.3V)
V
EE
........................................................ 10V to 0.3V
Short-Circuit Duration
Transmitter Output ..................................... Indefinite
Receiver Output .......................................... Indefinite
V
EE
................................................................. 30 sec
Operating Temperature Range
Commercial ............................................ 0
C to 70
C
Industrial ........................................... 40
C to 85
C
Storage Temperature Range ................ 65
C to 150
C
Lead Temperature (Soldering, 10 sec)................. 300
C
1
2
3
4
5
6
7
8
9
10
11
12
13
14
28
27
26
25
24
23
22
21
20
19
18
17
16
15
C2
+
C1
+
V
CC
C1
GND
T1
T2
T3
S1
S2
R3
R2
R1
OE
C2
V
EE
Y1
Z1
Y2
Z2
Y3
Z3
B3
A3
B2
A2
B1
A1
NW PACKAGE
28-LEAD PDIP
SW PACKAGE
28-LEAD PLASTIC SO
TOP VIEW
LTC1345CNW
LTC1345CSW
LTC1345INW
LTC1345ISW
ABSOLUTE AXI U RATI GS
W
W
W
U
PACKAGE/ORDER I FOR ATIO
U
U
W
DC ELECTRICAL CHARACTERISTICS
3
LTC1345
Note 1: The absolute maximum ratings are those values beyond which the
safety of the device cannot be guaranteed.
Note 2: All currents into device pins are termed positive; all currents out of
device pins are termed negative. All voltages are referenced to device
ground unless otherwise specified.
Note 3: All typicals are given for V
CC
= 5V, C1 = C2 = C3 = 1
F ceramic
capacitors and T
A
= 25
C.
Note 4: Maximum data rate is specified for NRZ data encoding scheme.
The maximum data rate may be different for other data encoding schemes.
Data rate is guaranteed by correlation and is not tested.
TEMPERATURE (C)
50
OUTPUT CURRENT
(mA)
25
LTC1345 TPC01
11
10
25
0
50
9
13
12
75
100
125
V
CC
= 5V
Transmitter Output Current
vs Temperature
TEMPERATURE (C)
50
TIME (ns)
25
LTC1345 TPC03
10
5
25
0
50
0
20
15
75
100
125
V
CC
= 5V
Transmitter Output Skew
vs Temperature
OUTPUT VOLTAGE (V)
2.0
OUTPUT CURRENT
(mA)
11
12
2.0
LTC1345 TPC02
10
9
1.0
0
1.0
13
1.5
0.5
0.5
1.5
T
A
= 25
C
V
CC
= 5V
Transmitter Output Current
vs Output Voltage
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
t
R
, t
F
Transmitter Rise or Fall Time
Figures 1 and 3, V
OS
= 0V
q
7
40
ns
t
PLH
Transmitter Input to Output
Figures 1 and 3, V
OS
= 0V
q
25
70
ns
t
PHL
Transmitter Input to Output
Figures 1 and 3, V
OS
= 0V
q
25
70
ns
t
SKEW
Transmitter Output to Output
Figures 1 and 3, V
OS
= 0V
0
ns
t
PLH
Receiver Input to Output
Figures 1 and 4, V
OS
= 0V
q
49
100
ns
t
PHL
Receiver Input to Output
Figures 1 and 4, V
OS
= 0V
q
52
100
ns
t
SKEW
Differential Receiver Skew, t
PLH
t
PHL
Figures 1 and 4, V
OS
= 0V
3
ns
t
ZL
Receiver Enable to Output LOW
Figures 2 and 5, C
L
= 15pF, S1 Closed
q
40
70
ns
t
ZH
Receiver Enable to Output HIGH
Figures 2 and 5, C
L
= 15pF, S2 Closed
q
35
70
ns
t
LZ
Receiver Disable From LOW
Figures 2 and 5, C
L
= 15pF, S1 Closed
q
30
70
ns
t
HZ
Receiver Disable From HIGH
Figures 2 and 5, C
L
= 15pF, S2 Closed
q
35
70
ns
f
OSC
Charge Pump Oscillator Frequency
200
kHz
BR
MAX
Maximum Data Rate (Note 4)
q
10
15
Mbaud
AC ELECTRICAL CHARACTERISTICS
The
q
denotes specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25
C. V
CC
= 5V
5% (Notes 2, 3), unless otherwise specified.
TYPICAL PERFOR A CE CHARACTERISTICS
U
W
4
LTC1345
Receiver
t
PLH
t
PHL
vs Temperature
TEMPERATURE (C)
50
TIME (ns)
25
LTC1345 TPC04
10
5
25
0
50
0
20
15
75
100
125
V
CC
= 5V
V
EE
Voltage vs Temperature
TEMPERATURE (C)
50
VOLTAGE (V)
25
LTC1345 TPC06
5.5
6.0
25
0
50
6.5
4.5
5.0
75
100
125
V
CC
= 5V
Supply Current vs Temperature
TEMPERATURE (C)
50
CURRENT (mA)
CURRENT (mA)
25
LTC1345 TPC05
100
80
25
0
50
60
140
120
20
15
10
30
25
75
100
125
V
CC
= 5V
LOADED
NO LOAD
Receiver Output Waveforms
R3 (Pin 11): Receiver 3 Output.
R2 (Pin 12): Receiver 2 Output.
R1 (Pin 13): Receiver 1 Output.
OE (Pin 14): Receiver Output Enable.
A1 (Pin 15): Receiver 1 Inverting Input.
B1 (Pin 16): Receiver 1 Noninverting Input.
A2 (Pin 17): Receiver 2 Inverting Input.
B2 (Pin 18): Receiver 2 Noninverting Input.
A3 (Pin 19): Receiver 3 Inverting Input.
B3 (Pin 20): Receiver 3 Noninverting Input.
Z3 (Pin 21): Transmitter 3 Inverting Output.
C2
+
(Pin 1): Capacitor C2 Positive Terminal.
C1
+
(Pin 2): Capacitor C1 Positive Terminal.
V
CC
(Pin 3): Positive Supply, 4.75
V
CC
5.25V.
C1
(Pin 4): Capacitor C1 Negative Terminal.
GND (Pin 5): Ground. The positive terminal of C3 is
connected to ground.
T1 (Pin 6): Transmitter 1 Input.
T2 (Pin 7): Transmitter 2 Input.
T3 (Pin 8): Transmitter 3 Input.
S1 (Pin 9): Select Input 1.
S2 (Pin 10): Select Input 2.
Transmitter Output Waveforms
INPUT
5V/DIV
OUTPUT
5V/DIV
OUTPUT
0.2V/DIV
LTC1345 TPC07
INPUT
0.2/DIV
LTC1345 TPC08
TYPICAL PERFOR A CE CHARACTERISTICS
U
W
U
U
U
PI FU CTIO S
5
LTC1345
Y3 (Pin 22): Transmitter 3 Noninverting Output.
Z2 (Pin 23): Transmitter 2 Inverting Output.
Y2 (Pin 24): Transmitter 2 Noninverting Output
Z1 (Pin 25): Transmitter 1 Inverting Output.
Y1 (Pin 26): Transmitter 1 Noninverting Output.
V
EE
(Pin 27): Charge Pump Output. Connected to negative
terminal of capacitor C3.
C2
(Pin 28): Capacitor C2 Negative Terminal.
Transmitter and Receiver Configuration
S1
S2
TX#
RX#
REMARKS
0
0
--
--
Shutdown
1
0
1, 2, 3
1, 2
DCE Mode, RX3 Shut Down
0
1
1, 2
1, 2, 3
DTE Mode, TX3 Shut Down
1
1
1, 2, 3
1, 2, 3
All Active
Transmitter
INPUTS
OUTPUTS
CONFIGURATION
S1 S2
T
Y1 AND Y2
Z1 AND Z2
Y3
Z3
DTE
0
1
0
0
1
Z
Z
DTE
0
1
1
1
0
Z
Z
DCE or All ON
1
X
0
0
1
0
1
DCE or All ON
1
X
1
1
0
1
0
Shutdown
0
0
X
Z
Z
Z
Z
Receiver
INPUTS
OUTPUTS
CONFIGURATION
S1 S2 OE
B A
R1 AND R2
R3
DTE or All ON
X
1
0
0.2V
1
1
DTE or All ON
X
1
0
0.2V
0
0
DCE
1
0
0
0.2V
1
Z
DCE
1
0
0
0.2V
0
Z
Disabled
X
X
1
X
Z
Z
Shutdown
0
0
X
X
Z
Z
15pF
OE
R
50
125
Y
Z
Z
Y
T
125
50
50
LTC1345 F01
50
B
A
V
OD
V
OS
V
OC
= (V
Y
+ V
Z
)/2
Figure 1. V.35 Transmitter/Receiver Test Circuit
Figure 2. Receiver Output Enable/Disable Timing Test Load
C
L
1k
LTC1345 F02
S1
S2
V
CC
RECEIVER
OUTPUT
U
U
U
PI FU CTIO S
FU CTIO TABLES
U
U
TEST CIRCUITS
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