LTC2845
3.3V Software-Selectable
Multiprotocol Transceiver
FEATURES
s
s
DESCRIPTIO
s
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 or
a Single 5V Supply with 3.3V Logic with LTC2847
TUV Rheinland of North America Inc. Certified NET1,
NET2 and TBR2 Compliant,
Report No.: TBR2/050101/02
Complete DTE or DCE Port with LTC2846 or LTC2847
Available in a 36-Lead Narrow (0.209") SSOP and
38-Lead (7mm x 5mm) QFN package
The LTC
®
2845 is a 5-driver/5-receiver multiprotocol trans-
ceiver. The LTC2845 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 LTC2845 operates from a 3.3V supply and supplies
provided by the LTC2846. This part is available in a 36-lead
SSOP and 38-lead (7mm x 5mm) QFN package. The LTC2845
and LTC2847 in QFN packages offer the smallest multiprotocol
serial port available.
, 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
RL
TM
RI
LL
CTS
DSR
DCD
DTR
RTS
RXD
RXC
TXC
SCTE
TXD
LTC2845
D5
R5
R4
D4
D3
R3
R2
R1
D2
D1
R3
R2
R1
T
T
21
RL A (140)
25
TM A (142)
*
RI A (125)
18 13 5
LL A (141)
CTS B
CTS A (106)
DSR B
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
U
LTC2846
D3
D2
D1
T
T
T
12
TXC B
TXC A (114)
U
U
15 11
SCTE B
SCTE A (113)
24 14
TXD B
2
TXD A (103)
*OPTIONAL
2845 TA01
sn2845 2845fs
1
LTC2845
ABSOLUTE
MAXIMUM
RATINGS
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)
PACKAGE/ORDER INFORMATION
TOP VIEW
V
CC
V
DD
D1
D2
D3
R1
R2
R3
D4
1
2
3
4
5
6
7
8
9
R1
R2
R3
D4
R4
R5
D5
G PACKAGE
36-LEAD PLASTIC SSOP
D3
D1
D2
36 V
EE
35 GND
34 D1 A
33 D1 B
32 D2 A
31 D2 B
30 D3/R1 A
29 D3/R1 B
28 R2 A
27 R2 B
26 R3 A
25 R3 B
24 D4 A
23 R4 A
22 R5 A
21 D5 A
20 V
IN
19 V
CC
ORDER PART
NUMBER
LTC2845CG
LTC2845IG
D2 1
D3 2
R1 3
R2 4
R3 5
D4 6
R4 7
M0 8
M1 9
M2 10
NC 11
DCE/DTE 12
38 37 36 35 34 33 32
31 D1 B
30 D2 A
29 D2 B
28 D3/R1 A
27 D3/R1 B
39
26 R2 A
25 R2 B
24 R3 A
23 R3 B
22 D4 A
21 R4 A
20 R5 A
13 14 15 16 17 18 19
R5
D5
V
CC
V
IN
D4ENB
R4EN
D5 A
D1 A
GND
V
DD
V
CC
V
EE
V
EE
D1
R4 10
M0 11
M1 12
M2 13
DCE/DTE 14
D4ENB 15
R4EN 16
R5 17
D5 18
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
2
U
U
W
W W
U
W
(Note 1)
Short-Circuit Duration
Transmitter Output ..................................... Indefinite
Receiver Output .......................................... Indefinite
V
EE
.................................................................. 30 sec
Operating Temperature Range
LTC2845C ............................................... 0°C to 70°C
LTC2845I ........................................... – 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
LTC2845CUHF
LTC2845IUHF
UHF PART
MARKING
2845
2845I
UHF PACKAGE
38-LEAD (7mm
×
5mm) PLASTIC QFN
T
JMAX
= 125°C,
θ
JA
= 34°C/ W
EXPOSED PAD IS V
EE
(PIN 39)
MUST BE SOLDERED TO PCB
MIN
TYP
2.7
110
1
1
700
MAX
UNITS
mA
mA
mA
mA
µA
sn2845 2845fs
150
3
3
1400
LTC2845
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
I
EE
PARAMETER
V
EE
Supply Current (DCE Mode,
All Digital Pins = GND or V
IN
)
CONDITIONS
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
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
RS530, RS530-A, X.21 Modes, Full Load
V.28 Mode, Full Load
q
ELECTRICAL CHARACTERISTICS
MIN
TYP
2
23
34
1
12
10
0.3
0.3
1
13.5
10
650
240
64
MAX
UNITS
mA
mA
mA
mA
mA
µA
mA
mA
mA
mA
µA
µA
mW
mW
V
I
DD
V
DD
Supply Current (DCE Mode,
All Digital Pins = GND or V
IN
)
I
VIN
P
D
V
IN
Supply Current (DCE Mode,
All Digital Pins = GND or V
IN
)
Internal Power Dissipation (DCE Mode,
All Digital Pins = GND or V
IN
)
Logic Input High Voltage
Logic Input Low Voltage
Logic Input Current
Logic Inputs and Outputs
V
IH
V
IL
I
IN
2
0.8
0.5
–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
CC
= 5V
R4EN when V
CC
= 3.3V
D1, D2, D3, D4, D5
M0, M1, M2, DCE, D4ENB, R4EN = GND
M0, M1, M2, DCE, D4ENB, R4EN = V
IN
I
O
= –3mA
I
O
= 1.6mA
0V
≤
V
O
≤
V
IN
M0 = M1 = M2 = V
IN
, V
O
= GND
M0 = M1 = M2 = V
IN
, V
O
= V
IN
R
L
= 1.95k (Figure 1)
R
L
= 50Ω (Figure 1)
q
q
q
q
q
q
q
q
q
V
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
sn2845 2845fs
±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
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
q
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
LTC2845C (Figures 2, 5)
LTC2845I (Figures 2, 5)
LTC2845C (Figures 2, 5)
LTC28451 (Figures 2, 5)
LTC2845C (Figures 2, 5)
LTC2845I (Figures 2, 5)
LTC2845C (Figures 2, 5)
LTC2845I (Figures 2, 5)
(Figures 2, 5)
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
3
LTC2845
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
V
TH
∆V
TH
I
IN
R
IN
t
r
, t
f
t
PLH
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
Output Voltage
Short-Circuit Current
Output Leakage Current
Slew Rate
Input to Output
Input to Output
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
q
q
q
q
q
ELECTRICAL CHARACTERISTICS
PARAMETER
Input Threshold Voltage
Input Hysteresis
Input Current (A, B)
Input Impedance
Rise or Fall Time
Input to Output
Input to Output
Input to Output Difference,
t
PLH
– t
PHL
CONDITIONS
–7V
≤
V
CM
≤
7V
–7V
≤
V
CM
≤
7V
–10V
≤
V
A,B
≤
10V
–10V
≤
V
A,B
≤
10V
(Figures 2, 6)
LTC2845C C
L
= 50pF (Figures 2, 6)
LTC2845I C
L
= 50pF (Figures 2, 6)
LTC2845C C
L
= 50pF (Figures 2, 6)
LTC2845I C
L
= 50pF (Figures 2, 6)
LTC2845C C
L
= 50pF (Figures 2, 6)
LTC2845I 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
q
q
q
q
q
q
MIN
–0.2
TYP
MAX
0.2
UNITS
V
mV
mA
kΩ
ns
V.11 Receiver
15
15
30
15
50
50
50
50
0
0
±4
±3.6
0.9V
O
±150
±0.1
2
1
1
–0.25
25
15
30
15
55
109
60
±10
±150
±1
4
1.3
1.3
±100
30
2.5
2.5
0.25
50
±0.66
±100
4
4
80
90
80
90
16
21
±6
40
±0.66
ns
ns
ns
ns
ns
ns
V
V
mA
µA
µs
µs
µs
V
mV
mA
kΩ
ns
ns
ns
ns
V
V
mA
µA
V/µs
µs
µs
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
V.10 Receiver
–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)
q
q
±5
±8.5
sn2845 2845fs
4
LTC2845
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
PARAMETER
V.28 Receiver
V
THL
Input Low Threshold Voltage
V
TLH
Input High Threshold Voltage
∆V
TH
Receiver Input Hysterisis
R
IN
Receiver Input Impedance
t
r
, t
f
Rise or Fall Time
t
PLH
Input to Output
t
PHL
Input to Output
CONDITIONS
q
q
q
ELECTRICAL CHARACTERISTICS
MIN
TYP
MAX
0.8
UNITS
V
V
V
kΩ
ns
ns
ns
2
3
0.1
5
15
60
150
0.3
7
100
500
–15V
≤
V
A
≤
15V
C
L
= 50pF (Figures 4, 8)
C
L
= 50pF (Figures 4, 8)
C
L
= 50pF (Figures 4, 8)
q
q
q
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, Two V.10 Drivers
with Full Load) I
CC
vs Data Rate
140
T
A
= 25°C
135
130
34
30
28
34
T
A
= 25°C
I
CC
(mA)
I
DD
(mA)
I
EE
(mA)
125
120
115
110
105
10
100
1000
DATA RATE (kBd)
10000
2845 G01
125
120
115
RS530, X.21 in DCE Mode
(Three V.11, Two V.10 Drivers with
Full Load) I
CC
vs Temperature
34.6
34.4
34.2
110
105
100
95
–40 –20
33.8
33.6
33.4
33.2
I
DD
(mA)
I
CC
(mA)
I
EE
(mA)
20
60
0
40
TEMPERATURE (°C)
U W
80
2845 G04
RS530-A in DCE Mode
(Three V.10 Drivers with Full
Load) I
EE
vs Data Rate
16
15
14
13
12
11
10
9
8
10
30 40 50 60 70 80 100
20
DATA RATE (kBd)
2845 G02
7
V.28 in DCE Mode
(Five V.28 Drivers with Full Load)
I
DD
vs Data Rate
T
A
= 25°C
26
24
22
20
18
10
20
30 40 50 60 70 80 100
2845 G03
DATA RATE (kBd)
RS530-A in DCE Mode
(Three V.10 Drivers with Full
Load) I
EE
vs Temperature
13.9
13.8
13.7
13.6
13.5
13.4
13.3
13.2
0
20
40
60
TEMPERATURE (°C)
80
100
V.28 in DCE Mode
(Five V.28 Drivers with Full Load)
I
DD
vs Temperature
34.0
100
33.0
–40 –20
13.1
–40 –20
2845 G05
0
20
40
60
TEMPERATURE (°C)
80
100
2845 G06
sn2845 2845fs
5
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