LTC1546
Software-Selectable
Multiprotocol Transceiver
with Termination
FEATURES
s
s
DESCRIPTIO
s
s
s
s
s
Software-Selectable Transceiver Supports:
RS232, RS449, EIA530, EIA530-A, V.35, V.36, X.21
TUV Telecom Services Inc. Certified NET1,
NET2 and TBR2 Compliant
On-Chip Cable Termination
Pin Compatible with LTC1543
Complete DTE or DCE Port with LTC1544
Operates from Single 5V Supply
Small Footprint
APPLICATIO S
s
s
s
Data Networking
CSU and DSU
Data Routers
The LTC
®
1546 is a 3-driver/3-receiver multiprotocol trans-
ceiver with on-chip cable termination. When combined with
the LTC1544, this chip set forms a complete software-
selectable DTE or DCE interface port that supports the
RS232, RS449, EIA530, EIA530-A, V.35, V.36 and X.21
protocols. All necessary cable termination is provided inside
the LTC1546. In most applications, the LTC1546 replaces
both an LTC1543 and an LTC1344A without any changes to
the PC board.
The LTC1546 runs from a single 5V supply using an internal
charge pump that requires only five space-saving surface
mounted capacitors. The LTC1546 is available in a 28-lead
SSOP surface mount package.
, LTC and LT are registered trademarks of Linear Technology Corporation.
TYPICAL APPLICATION
Complete DTE or DCE Multiprotocol Serial Interface with DB-25 Connector
LL
CTS
DSR
DCD
DTR
RTS
RXD
RXC
TXC
SCTE
TXD
LTC1544
D4
R4
R3
R2
R1
D3
D2
D1
R3
R2
R1
T
T
18
LL A (141)
13 5
DSR B
CTS B
CTS A (106)
22 6
DSR A (107)
10 8
DCD B
DCD A (109)
23 20 19 4
DTR B
DTR A (108)
RTS B
RTS A (105)
SHIELD (101)
1
SG (102)
7
16
RXD B
3
RXD A (104)
9
RXC B
17
RXC A (115)
DB-25 CONNECTOR
1546 TA01
U
LTC1546
D3
D2
D1
T
T
T
12
TXC B
U
U
15 11
TXC A (114)
SCTE B
24 14
SCTE A (113)
TXD B
2
TXD A (103)
1
LTC1546
ABSOLUTE
(Note 1)
AXI U
RATI GS
PACKAGE/ORDER I FOR ATIO
TOP VIEW
C1
–
C1
+
V
DD
V
CC
D1
D2
D3
R1
R2
1
2
3
4
5
D1
6
7
8
9
T
R3 10
M0 11
M1 12
M2 13
DCE/DTE 14
G PACKAGE
28-LEAD PLASTIC SSOP
R2
R3
T
17 R2 B
16 R3 A
T
15 R3 B
R1
19 D3/R1 B
18 R2 A
D2
D3
T
T
23 D1 B
22 D2 A
21 D2 B
20 D3/R1 A
CHARGE PUMP
28 C2
+
27 C2
–
26 V
EE
25 GND
24 D1 A
Supply Voltage ....................................................... 6.5V
Input Voltage
Transmitters ........................... – 0.3V to (V
CC
+ 0.3V)
Receivers ............................................... – 18V to 18V
Logic Pins .............................. – 0.3V to (V
CC
+ 0.3V)
Output Voltage
Transmitters ................. (V
EE
– 0.3V) to (V
DD
+ 0.3V)
Receivers ................................ – 0.3V to (V
CC
+ 0.3V)
V
EE
........................................................ – 10V to 0.3V
V
DD
....................................................... – 0.3V to 10V
Short-Circuit Duration
Transmitter Output ..................................... Indefinite
Receiver Output .......................................... Indefinite
V
EE
.................................................................. 30 sec
Operating Temperature Range
LTC1546C ............................................... 0°C to 70°C
LTC1546I ........................................... – 40°C to 85°C
Storage Temperature Range ................ – 65°C to 150°C
Lead Temperature (Soldering, 10 sec)................. 300°C
ORDER PART
NUMBER
LTC1546CG
LTC1546IG
T
JMAX
= 150°C,
θ
JA
= 90°C/ W*
*θ
JA
SOLDERED TO A CIRCUIT BOARD
IS TYPICALLY 60°C/W
Consult factory for parts specified with wider operating temperature ranges.
ELECTRICAL CHARACTERISTICS
SYMBOL
Supplies
I
CC
V
CC
Supply Current (DCE Mode,
All Digital Pins = GND or V
CC
)
PARAMETER
The
q
denotes specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
CC
= 5V (Notes 2, 3)
CONDITIONS
RS530, RS530-A, X.21 Modes, No Load
RS530, RS530-A, X.21 Modes, Full Load
V.35 Mode
V.28 Mode, No Load
V.28 Mode, Full Load
No-Cable Mode
RS530, RS530-A, X.21 Modes, Full Load
V.35 Mode, Full Load
V.28 Mode, Full Load
V.11 or V.28 Mode, No Load
V.35 Mode
V.28 Mode, with Load
V.28 Mode, with Load, I
DD
= 10mA
V.28 Mode, No Load
V.28 Mode, Full Load
V.35 Mode
RS530, RS530-A, X.21 Modes, Full Load
q
q
q
MIN
TYP
14
100
126
20
35
60
410
625
150
MAX
UNITS
mA
mA
mA
mA
mA
µA
mW
mW
mW
V
V
V
V
V
V
V
V
q
q
q
q
130
170
75
500
P
D
Internal Power Dissipation (DCE Mode)
V
+
Positive Charge Pump Output Voltage
8.0
7.0
8.0
9.3
8.0
8.7
6.5
– 9.6
– 8.5
– 6.5
– 6.0
V
–
Negative Charge Pump Output Voltage
q
q
q
– 7.5
– 5.5
– 4.5
2
U
W
U
U
W W
W
LTC1546
ELECTRICAL CHARACTERISTICS
SYMBOL
f
OSC
t
r
V
IH
V
IL
I
IN
PARAMETER
Charge Pump Oscillator Frequency
Charge Pump Rise Time
Logic Input High Voltage
Logic Input Low Voltage
Logic Input Current
D1, D2, D3
M0, M1, M2, DCE = GND
M0, M1, M2, DCE = V
CC
I
O
= – 3mA
I
O
= 3mA
0V
≤
V
O
≤
V
CC
M0 = M1 = M2 = V
CC
, 0V
≤
V
O
≤
V
CC
R
L
= 1.95k (Figure 1)
R
L
= 50Ω (Figure 1)
R
L
= 50Ω (Figure 1)
R
L
= 50Ω (Figure 1)
R
L
= 50Ω (Figure 1)
R
L
= 50Ω (Figure 1)
V
OUT
= GND
V
A
and
V
B
≤
0.25V, Power Off or
q
q
q
q
q
q
q
q
q
q
The
q
denotes specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
CC
= 5V (Notes 2, 3)
CONDITIONS
No-Cable Mode/Power-Off to Normal Operation
q
q
q
q
q
q
q
q
MIN
TYP
500
2
MAX
UNITS
kHz
ms
V
Logic Inputs and Outputs
2
0.8
– 120
3
– 50
±1
±
5
0.5V
ODO
±2
0.67V
ODO
0.2
3
0.2
±150
±
1
2
15
15
0
15
40
40
3
3
q
q
q
V
µA
µA
µA
V
V
mA
µA
V
V
V
V
V
V
mA
µA
ns
ns
ns
ns
ns
– 75
4.5
0.3
±10
– 30
±10
0.45
50
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
t
r
, t
f
t
PLH
t
PHL
∆t
t
SKEW
V
TH
∆V
TH
R
IN
t
r
, t
f
t
PLH
t
PHL
∆t
V.35 Driver
V
OD
V
OA
, V
OB
V
OC
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 Rising
Input to Output Falling
Input to Output Difference,
t
PLH
– t
PHL
Output to Output Skew
Input Threshold Voltage
Input Hysteresis
Input Impedance
Rise or Fall Time
Input to Output Rising
Input to Output Falling
Input to Output Difference,
t
PLH
– t
PHL
Differential Output Voltage
Single-Ended Output Voltage
Transmitter Output Offset
±100
25
65
65
12
No-Cable Mode or Driver Disabled
(Figures 2, 13)
(Figures 2, 13)
(Figures 2, 13)
(Figures 2, 13)
(Figures 2, 13)
– 7V
≤
V
CM
≤
7V
– 7V
≤
V
CM
≤
7V
–7V
≤
V
CM
≤
7V (Figure 3)
C
L
= 50pF (Figures 4, 14)
C
L
= 50pF (Figures 4, 14)
C
L
= 50pF (Figures 4, 14)
C
L
= 50pF (Figures 4, 14)
Open Circuit, R
L
= 1.95k (Figure 5)
With Load, – 4V
≤
V
CM
≤
4V (Figure 6)
Open Circuit, R
L
= 1.95k (Figure 5)
R
L
= 50Ω (Figure 5)
q
q
q
V.11 Receiver
– 0.2
15
100
103
15
50
50
0
4
90
90
25
±1.2
±0.66
±1.2
±0.6
0.2
40
V
mV
Ω
ns
ns
ns
ns
V
V
V
V
q
±0.44
q
q
±0.55
3
LTC1546
ELECTRICAL CHARACTERISTICS
SYMBOL
I
OH
I
OL
I
OZ
R
OD
R
OC
t
r
, t
f
t
PLH
t
PHL
∆t
t
SKEW
V
TH
∆V
TH
R
ID
R
IC
t
r
, t
f
t
PLH
t
PHL
∆t
V.28 Driver
V
O
I
SS
R
OZ
SR
t
PLH
t
PHL
V
THL
V
TLH
∆V
TH
R
IN
t
r
, t
f
t
PLH
t
PHL
Output Voltage
Short-Circuit Current
Power-Off Resistance
Slew Rate
Input to Output
Input to Output
Input Low Threshold Voltage
Input High Threshold Voltage
Receiver Input Hysteresis
Receiver Input Impedance
Rise or Fall Time
Input to Output
Input to Output
PARAMETER
Transmitter Output High Current
Transmitter Output Low Current
Transmitter Output Leakage Current
Transmitter Differential Mode Impedance
Transmitter Common Mode Impedance
Rise or Fall Time
Input to Output
Input to Output
Input to Output Difference,
t
PLH
– t
PHL
Output to Output Skew
Differential Receiver Input Threshold Voltage
Receiver Input Hysteresis
Receiver Differential Mode Impedance
Receiver Common Mode Impedance
Rise or Fall Time
Input to Output
Input to Output
Input to Output Difference,
t
PLH
– t
PHL
The
q
denotes specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
CC
= 5V (Notes 2, 3)
CONDITIONS
V
A
, V
B
= 0V
V
A
, V
B
= 0V
V
A
and
V
B
≤
0.25V
q
q
q
q
MIN
– 13
9.0
50
135
q
q
q
TYP
– 11
11
±1
100
150
5
35
35
0
4
MAX
– 9.0
13
±100
150
165
65
65
16
UNITS
mA
mA
µA
Ω
Ω
ns
ns
ns
ns
ns
– 2V
≤
V
CM
≤
2V (Figure 7)
(Figures 8, 13)
(Figures 8, 13)
(Figures 8, 13)
(Figures 8, 13)
(Figures 8, 13)
– 2V
≤
V
CM
≤
2V (Figure 9)
– 2V
≤
V
CM
≤
2V (Figure 9)
– 2V
≤
V
CM
≤
2V
– 2V
≤
V
CM
≤
2V (Figure 10)
C
L
= 50pF (Figures 4, 14)
C
L
= 50pF (Figures 4, 14)
C
L
= 50pF (Figures 4, 14)
C
L
= 50pF (Figures 4, 14)
Open Circuit
R
L
= 3k (Figure 11)
V
OUT
= GND
– 2V < V
O
< 2V, Power Off
or No-Cable Mode
R
L
= 7k, C
L
= 0 (Figures 11, 15)
R
L
= 3k, C
L
= 2500pF (Figures 11, 15)
R
L
= 3k, C
L
= 2500pF (Figures 11, 15)
(Figure 12)
(Figure 12)
(Figure 12)
– 15V
≤
V
A
≤
15V
C
L
= 50pF (Figures 12, 16)
C
L
= 50pF (Figures 12, 16)
C
L
= 50pF (Figures 12, 16)
q
q
q
q
q
q
q
q
15
15
V.35 Receiver
– 0.2
15
90
135
103
150
15
50
50
0
4
90
90
25
±10
±150
300
4
1.5
1.5
1.2
2
0
3
1.2
0.05
5
15
60
160
300
300
0.3
7
30
2.5
2.5
0.8
0.2
40
110
165
V
mV
Ω
Ω
ns
ns
ns
ns
V
V
mA
Ω
V/µs
µs
µs
V
V
V
kΩ
ns
ns
ns
q
q
q
q
q
q
q
±5
±8.5
V.28 Receiver
q
q
q
q
Note 1:
Absolute Maximum Ratings are those values beyond which the life
of the 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 V
CC
= 5V, C1 = C2 = C
VCC
= C
VDD
= 1µF,
C
VEE
= 3.3µF and T
A
= 25°C.
4
LTC1546
TYPICAL PERFOR A CE CHARACTERISTICS
V.11 Mode
Supply Current vs Data Rate
180
170
SUPPLY CURRENT (mA)
SUPPLY CURRENT (mA)
150
140
130
120
110
100
90
10
100
1000
DATA RATE (kBd)
10000
1546 • G01
SUPPLY CURRENT (mA)
10
100
1000
DATA RATE (kBd)
10000
1546 • G02
160
V.11 Mode
I
CC
vs Temperature
115
110
105
135
I
CC
(mA)
I
CC
(mA)
100
95
90
85
–40 –20
I
CC
(mA)
40
20
60
0
TEMPERATURE (°C)
PI FU CTIO S
C1
–
(Pin 1):
Capacitor C1 Negative Terminal. Connect a
1µF capacitor between C1
+
and C1
–
.
C1
+
(Pin 2):
Capacitor C1 Positive Terminal. Connect a
1µF capacitor between C1
+
and C1
–
.
V
DD
(Pin 3):
Generated Positive Supply Voltage for
V.28. Connect a 1µF capacitor to ground.
V
CC
(Pin 4):
Positive Supply Voltage Input. 4.75V
≤
V
CC
≤
5.25V. Bypass with a 1µF capacitor to ground.
D1 (Pin 5):
TTL Level Driver 1 Input.
D2 (Pin 6):
TTL Level Driver 2 Input.
D3 (Pin 7):
TTL Level Driver 3 Input.
R1 (Pin 8):
CMOS Level Receiver 1 Output.
R2 (Pin 9):
CMOS Level Receiver 2 Output.
R3 (Pin 10):
CMOS Level Receiver 3 Output.
M0 (Pin 11):
TTL Level Mode Select Input 0 with Pull-Up
to V
CC
. See Table 1.
M1 (Pin 12):
TTL Level Mode Select Input 1 with Pull-Up
to V
CC
. See Table 1.
M2 (Pin 13):
TTL Level Mode Select Input 2 with Pull-Up
to V
CC
. See Table 1.
DCE/DTE (Pin 14):
TTL Level Mode Select Input with Pull-
Up to V
CC
. See Table 1.
U W
80
V.35 Mode
Supply Current vs Data Rate
150
V.28 Mode
Supply Current vs Data Rate
35
34
145
33
140
32
135
31
130
30
10
20
50
DATA RATE (kBd)
100
1546 • G03
V.35 Mode
I
CC
vs Temperature
140
40
V.28 Mode
I
CC
vs Temperature
38
36
34
130
32
100
125
–40 –20
40
20
60
0
TEMPERATURE (°C)
80
100
30
–40 –20
40
20
60
0
TEMPERATURE (°C)
80
100
1546 • G04
1546 • G05
1546 • G06
U
U
U
5
PCB设计
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