LTC2844
3.3V Software-Selectable
Multiprotocol Transceiver
FEATURES
s
s
s
DESCRIPTIO
s
s
Software-Selectable Transceiver Supports:
RS232, RS449, EIA530, EIA530-A, V.35, V.36, X.21
Operates from Single 3.3V Supply with LTC2846
TUV Rheinland of North America Inc. Certified NET1,
NET2 and TBR2 Compliant,
Report No.: TBR2/051501/02
Complete DTE or DCE Port with LTC2846
28-Lead SSOP Surface Mount Package
The LTC
®
2844 is a 4-driver/4-receiver multiprotocol trans-
ceiver. The LTC2844 and LTC2846 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.
The LTC2844 operates from a 3.3V supply and supplies
provided by the LTC2846. The part is available in a 28-lead
SSOP surface mount package.
, LTC and LT are registered trademarks of Linear Technology Corporation.
APPLICATIO S
s
s
s
Data Networking
CSU and DSU
Data Routers
TYPICAL APPLICATIO
DTE or DCE Multiprotocol Serial Interface with DB-25 Connector
LL
CTS
DSR
DCD
DTR
RTS
RXD
RXC
TXC
SCTE
TXD
LTC2844
D4
R4
R3
R2
R1
D3
D2
D1
R3
R2
LTC2846
D3
R1
D2
D1
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
2844 TA01
U
T
T
T
12
TXC B
15 11
TXC A (114)
SCTE B
24 14
SCTE A (113)
TXD B
2
TXD A (103)
sn2844 2844fs
U
U
1
LTC2844
ABSOLUTE
(Note 1)
AXI U
RATI GS
PACKAGE/ORDER I FOR ATIO
TOP VIEW
V
CC
V
DD
D1
D2
D3
R1
R2
R3
D4
1
2
3
D1
4
5
6
7
8
9
R1
R2
R3
D4
R4
D2
D3
25 D1 B
24 D2 A
23 D2 B
22 D3/R1 A
21 D3/R1 B
20 R2 A
19 R2 B
18 R3 A
17 R3 B
16 D4/R4 A
15 V
IN
G PACKAGE
28-LEAD PLASTIC SSOP
28 V
EE
27 GND
26 D1 A
Supply Voltage
V
CC
....................................................... –0.3V to 6.5V
V
IN .....................................................................
– 0.3V to 6.5V
V
EE ......................................................................
–10V to 0.3V
V
DD .....................................................................
– 0.3V to 10V
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
IN
+ 0.3V)
Short-Circuit Duration
Transmitter Output ...................................... Indefinite
Receiver Output ........................................... Indefinite
V
EE
................................................................... 30 sec
Operating Temperature Range
LTC2844CG ............................................. 0°C to 70°C
LTC2844IG ......................................... – 40°C to 85°C
Storage Temperature Range ................. – 65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
ORDER PART
NUMBER
LTC2844CG
LTC2844IG
R4 10
M0 11
M1 12
M2 13
DCE/DTE 14
T
JMAX
= 125°C,
θ
JA
= 90°C/ W,
θ
JC
= 35°C/ W
Consult LTC Marketing for parts specified with wider operating temperature ranges.
The
q
denotes specifications which apply over the full operating tempera-
ture range, otherwise specifications are at T
A
= 25°C. V
CC
= 5V, V
IN
= 3.3V, V
DD
= 8V, V
EE
= – 7V for V.28, – 5.5V for V.10, V.11
(Notes 2, 3)
SYMBOL
Supplies
I
CC
V
CC
Supply Current (DCE Mode,
All Digital Pins = GND or V
IN
)
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
q
q
q
q
ELECTRICAL CHARACTERISTICS
PARAMETER
CONDITIONS
MIN
TYP
2.7
95
1
1
600
1.6
14
25
1
7.5
10
0.2
0.2
1
8
10
490
MAX
UNITS
mA
mA
mA
mA
µA
mA
mA
mA
mA
mA
µA
mA
mA
mA
mA
µA
µA
120
2
2
1200
I
EE
V
EE
Supply Current (DCE Mode Unless
RS530, RS530-A, X.21 Modes, No Load
Otherwise Noted, All Digital Pins = GND or V
IN
) RS530, X.21 Modes, Full Load (DTE Mode)
RS530-A, Full Load (DTE Mode)
V.28 Mode, No Load
V.28 Mode, Full Load
No-Cable Mode
V
DD
Supply Current (DCE Mode,
All Digital Pins = GND or V
IN
)
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
All Modes Except No-Cable Mode
I
DD
I
VIN
V
IN
Supply Current (DCE Mode,
All Digital Pins = GND or V
IN
)
sn2844 2844fs
2
U
W
U
U
W W
W
LTC2844
The
q
denotes specifications which apply over the full operating tempera-
ture range, otherwise specifications are at T
A
= 25°C. V
CC
= 5V, V
IN
= 3.3V, V
DD
= 8V, V
EE
= – 7V for V.28, – 5.5V for V.10, V.11
(Notes 2, 3)
SYMBOL
P
D
PARAMETER
Internal Power Dissipation (DCE Mode,
All Digital Pins = GND or V
IN
)
Logic Input High Voltage
Logic Input Low Voltage
Logic Input Current
D1, D2, D3, D4
M0, M1, M2, DCE = GND
M0, M1, M2, DCE = V
IN
I
O
= –3mA
I
O
= 1.6mA
0V
≤
V
O
≤
V
IN
M0 = M1 = M2 = V
IN
, V
O
= 0V
M0 = M1 = M2 = V
IN
, V
O
= V
IN
R
L
= 1.95k (Figure 1)
R
L
= 50Ω (Figure 1)
q
ELECTRICAL CHARACTERISTICS
CONDITIONS
RS530, RS530-A, X.21 Modes, Full Load
V.28 Mode, Full Load
q
q
q
q
q
q
q
q
q
q
MIN
TYP
210
54
MAX
UNITS
mW
mW
V
Logic Inputs and Outputs
V
IH
V
IL
I
IN
2
0.8
– 30
2.7
– 75
3
0.2
– 30
– 85
0.4
±50
– 160
±10
±5
0.5V
ODO
±2
0.67V
ODO
0.2
3
0.2
±150
q
q
q
q
q
q
q
q
q
V
µA
µA
µA
V
V
mA
µA
µA
V
V
V
V
V
V
mA
µA
ns
ns
ns
ns
ns
ns
ns
ns
ns
±10
–120
±10
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
I
IN
R
IN
t
r
, t
f
t
PLH
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
Input to Output
Input to Output Difference,
t
PLH
– t
PHL
Output to Output Skew
Input Threshold Voltage
Input Hysteresis
Input Current (A, B)
Input Impedance
Rise or Fall Time
Input to Output
q
R
L
= 50Ω (Figure 1)
R
L
= 50Ω (Figure 1)
R
L
= 50Ω (Figure 1)
V
OUT
= GND
–0.25V
≤
V
O
≤
0.25V, Power Off or
No-Cable Mode or Driver Disabled
LTC2844C (Figures 2, 5)
LTC2844I (Figures 2, 5)
LTC2844C (Figures 2, 5)
LTC28441 (Figures 2, 5)
LTC2844C (Figures 2, 5)
LTC2844I (Figures 2, 5)
LTC2844C (Figures 2, 5)
LTC2844I (Figures 2, 5)
(Figures 2, 5)
–7V
≤
V
CM
≤
7V
–7V
≤
V
CM
≤
7V
–10V
≤
V
A,B
≤
10V
–10V
≤
V
A,B
≤
10V
(Figures 2, 6)
LTC2844C C
L
= 50pF (Figures 2, 6)
LTC2844I C
L
= 50pF (Figures 2, 6)
q
q
q
±1
2
2
20
20
20
20
0
0
15
15
40
40
40
40
3
3
3
±100
25
35
65
75
65
75
12
17
V.11 Receiver
q
q
q
q
– 0.2
15
15
30
15
50
50
0.2
40
±0.66
V
mV
mA
kΩ
ns
q
q
80
90
ns
ns
sn2844 2844fs
3
LTC2844
The
q
denotes specifications which apply over the full operating tempera-
ture range, otherwise specifications are at T
A
= 25°C. V
CC
= 5V, V
IN
= 3.3V, V
DD
= 8V, V
EE
= – 7V for V.28, – 5.5V for V.10, V.11
(Notes 2, 3)
SYMBOL
t
PHL
∆t
V.10 Driver
V
O
V
T
I
SS
I
OZ
t
r
, t
f
t
PLH
t
PHL
V
TH
∆V
TH
I
IN
R
IN
t
r
, t
f
t
PLH
t
PHL
∆t
V.28 Driver
V
O
I
SS
I
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
Output Leakage Current
Slew Rate
Input to Output
Input to Output
Input Low Threshold Voltage
Input High Threshold Voltage
Receiver Input Hysterisis
Receiver Input Impedance
Rise or Fall Time
Input to Output
Input to Output
–15V
≤
V
A
≤
15V
C
L
= 50pF (Figures 4, 8)
C
L
= 50pF (Figures 4, 8)
C
L
= 50pF (Figures 4, 8)
q
q
ELECTRICAL CHARACTERISTICS
PARAMETER
Input to Output
Input to Output Difference,
t
PLH
– t
PHL
CONDITIONS
LTC2844C C
L
= 50pF (Figures 2, 6)
LTC2844I C
L
= 50pF (Figures 2, 6)
LTC2844C C
L
= 50pF (Figures 2, 6)
LTC2844I C
L
= 50pF (Figures 2, 6)
Open Circuit, R
L
= 3.9k
R
L
= 450Ω (Figure 3)
R
L
= 450Ω (Figure 3)
V
O
= GND
–0.25V
≤
V
O
≤
0.25V, Power Off or
No-Cable Mode or Driver Disabled
R
L
= 450Ω, C
L
= 100pF (Figures 3, 7)
R
L
= 450Ω, C
L
= 100pF (Figures 3, 7)
R
L
= 450Ω, C
L
= 100pF (Figures 3, 7)
q
q
q
q
q
q
q
MIN
TYP
50
50
MAX
80
90
16
21
±6
UNITS
ns
ns
ns
ns
V
V
0
0
±4
±3.6
0.9V
O
4
4
Output Voltage
Output Voltage
Short-Circuit Current
Output Leakage Current
Rise or Fall Time
Input to Output
Input to Output
Receiver Input Threshold Voltage
Receiver Input Hysteresis
Receiver Input Current
Receiver Input Impedance
Rise or Fall Time
Input to Output
Input to Output
Input to Output Difference,
t
PLH
– t
PHL
q
q
±150
±0.1
2
1
1
–0.25
25
15
30
15
55
109
60
q
q
q
q
q
q
q
mA
µA
µs
µs
µs
±100
V.10 Receiver
0.25
50
±0.66
V
mV
mA
kΩ
ns
ns
ns
ns
±10
±150
±1
4
1.3
1.3
±100
30
2.5
2.5
0.8
2
0.1
3
5
15
60
150
100
500
0.3
7
V
V
mA
µA
V/µs
µs
µs
V
V
V
kΩ
ns
ns
ns
–10V
≤
V
A
≤
10V
–10V
≤
V
A
≤
10V
C
L
= 50pF (Figures 4, 8)
C
L
= 50pF (Figures 4, 8)
C
L
= 50pF (Figures 4, 8)
C
L
= 50pF (Figures 4, 8)
Open Circuit
R
L
= 3k (Figure 3)
V
O
= GND
–0.25V
≤
V
O
≤
0.25V, Power Off or
No-Cable Mode or Driver Disabled
R
L
= 3k, C
L
= 2500pF (Figures 3, 7)
R
L
= 3k, C
L
= 2500pF (Figures 3, 7)
R
L
= 3k, C
L
= 2500pF (Figures 3, 7)
q
q
±5
±8.5
V.28 Receiver
q
q
q
q
sn2844 2844fs
4
LTC2844
ELECTRICAL CHARACTERISTICS
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.
Note 3:
All typicals are given for V
CC
= 5V, V
IN
= 3.3V, V
DD
= 8V, V
EE
= – 7V
for V.28, – 5.5V for V.10, V.11 and T
A
= 25°C.
TYPICAL PERFOR A CE CHARACTERISTICS
RS530, X.21 in DCE Mode
(Three V.11 Drivers with Full
Load) I
CC
vs Data Rate
125
120
115
I
CC
(mA)
I
EE
(mA)
110
105
100
95
90
10
100
1000
DATA RATE (kBd)
10000
2844 G01
T
A
= 25°C
20
18
16
14
10
20
30 40 50 60 70 80 100
DATA RATE (kBd)
2844 G02
I
DD
(mA)
RS530, X.21 in DCE Mode
(Three V.11 Drivers with Full
Load) I
CC
vs Temperature
105
23.5
25.4
100
25.3
25.2
I
DD
(mA)
I
CC
(mA)
I
EE
(mA)
95
90
85
80
–40 –20
0
40
20
60
TEMPERATURE (°C)
U W
80
2844 G04
RS530-A in DTE Mode
(Two V.10 Drivers with Full Load)
I
EE
vs Data Rate
26
24
22
T
A
= 25°C
10
9
8
7
6
5
4
V.28 in DCE Mode
(Three V.28 Drivers with Full
Load) I
DD
vs Data Rate
T
A
= 25°C
10
20
30 40 50 60 70 80 100
DATA RATE (kBd)
2844 G03
RS530-A in DTE Mode
(Two V.10 Drivers with Full Load)
I
EE
vs Temperature
8.20
8.15
8.10
8.05
8.00
7.95
7.90
7.85
0
20
40
60
TEMPERATURE (°C)
80
100
V.28 in DCE Mode
(Three V.28 Drivers with Full
Load) I
DD
vs Temperature
25.1
25.0
24.9
24.8
24.7
24.6
100
24.5
–40 –20
7.80
–40 –20
0
20
40
60
TEMPERATURE (°C)
80
100
2844 G05
2844 G06
sn2844 2844fs
5
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