LTC2847
Software-Selectable
Multiprotocol Transceiver with
Termination and 3.3V Digital Interface
FEATURES
s
s
s
DESCRIPTIO
s
s
s
Software-Selectable Transceiver Supports:
RS232, RS449, EIA530, EIA530-A, V.35, V.36, X.21
Operates from Single 5V Supply
Separate Supply Pin for Digital Interface Works
down to 3V
On-Chip Cable Termination
Complete DTE or DCE Port with LTC2845
Available in 38-Pin 5mm
×
7mm QFN Package
APPLICATIO S
s
s
s
Data Networking
CSU and DSU
Data Routers
The LTC
®
2847 is a 3-driver/3-receiver multiprotocol trans-
ceiver with on-chip cable termination. When combined with
the LTC2845, 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 LTC2847.
The V
CC
supplies the drivers, the receivers and an internal
charge pump that requires only five space-saving surface
mounted capacitors. The V
IN
supply drives the digital inter-
face circuitry including the receiver output drivers. It can be
tied to V
CC
or be powered off a lower supply (down to 3V) to
interface with low voltage ASICs. The LTC2847 is available in
a 0.8mm tall, 5mm
×
7mm QFN package.
, LTC and LT are registered trademarks of Linear Technology Corporation.
TYPICAL APPLICATIO
Complete DTE or DCE Multiprotocol Serial Interface with DB-25 Connector
RL
TM
LL
RI
CTS
DSR
DCD
DTR
RTS
RXD
RXC
TXC
SCTE
TXD
LTC2845
D5
R5
D4
R4
R3
R2
R1
D3
D2
D1
R3
R2
T
T
21
25
18
*
13 5
22 6
10 8
23 20 19 4
1
7
16
3
9
DB-25 CONNECTOR
2847 TA01
*OPTIONAL
sn2847 2847fs
U
LTC2847
D3
R1
D2
D1
T
T
T
17
12
15 11
24 14
2
U
U
RI (125)
CTS B
CTS A (106)
DSR B
DSR A (107)
RL (140)
TM (142)
LL A (141)
DTR B
DTR A (108)
RTS B
RTS A (105)
SHIELD (101)
SG (102)
DCD B
DCD A (109)
TXC B
TXC A (114)
SCTE B
SCTE A (113)
TXD B
TXD A (103)
RXD B
RXD A (104)
RXC B
RXC A (115)
1
LTC2847
ABSOLUTE
(Note 1)
AXI U
RATI GS
PACKAGE/ORDER I FOR ATIO
TOP VIEW
C1
+
C2
–
C2
+
C1
–
V
EE
V
EE
V
EE
V
CC
Voltage.............................................. – 0.3V to 6.5V
V
IN
Voltage .............................................. – 0.3V to 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
IN
+ 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
LTC2847C ............................................... 0°C to 70°C
LTC2847I ........................................... – 40°C to 85°C
Storage Temperature Range ................ – 65°C to 150°C
Lead Temperature (Soldering, 10 sec)................. 300°C
ORDER PART
NUMBER
31 GND
30 GND
29 D1 A
28 D1 B
27 D2 A
26 D2 B
25 D3/R1 A
24 D3/R1 B
23 NC
22 NC
21 R2 A
20 R2 B
38 37 36 35 34 33 32
NC 1
V
DD
2
NC 3
V
CC
4
D1 5
D2 6
D3 7
R1 8
R2 9
R3 10
M0 11
M1 12
13 14 15 16 17 18 19
M2
DCE/DTE
R3 B
R3 A
NC
V
IN
NC
LTC2847CUHF
LTC2847IUHF
UHF PART
MARKING
2847
2847I
UHF PACKAGE
38-LEAD (7mm
×
5mm) PLASTIC QFN
UNDERSIDE METAL INTERNALLY CONNECTED TO V
EE
(PCB CONNECTION OPTIONAL)
T
JMAX
= 125°C,
θ
JA
= 34°C/W
Consult LTC Marketing 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
IN
)
PARAMETER
The
q
denotes specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
CC
= 5V, V
IN
= 3.3V, unless otherwise noted (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
All Modes Except 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
q
q
q
MIN
TYP
14
100
126
20
35
300
405
410
625
150
MAX
UNITS
mA
mA
mA
mA
mA
µA
µA
mW
mW
mW
V
V
V
V
q
q
q
q
130
170
75
900
I
VIN
P
D
V
IN
Supply Current
(DCE Mode, All Digital Pins = GND or V
IN
)
Internal Power Dissipation (DCE Mode)
V
+
Positive Charge Pump Output Voltage
8
7
8
9.3
8.0
8.7
6.5
sn2847 2847fs
2
U
W
U
U
W W
W
LTC2847
ELECTRICAL CHARACTERISTICS
SYMBOL
V
–
PARAMETER
Negative Charge Pump Output Voltage
The
q
denotes specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
CC
= 5V, V
IN
= 3.3V, unless otherwise noted (Notes 2, 3)
CONDITIONS
V.28 Mode, No Load
V.28 Mode, Full Load
V.35 Mode
RS530, RS530-A, X.21 Modes, Full Load
No-Cable Mode/Power-Off to Normal Operation
D1, D2, D3, M0, M1, M2, DCE/DTE
D1, D2, D3, M0, M1, M2, DCE/DTE
D1, D2, D3
M0, M1, M2, DCE/DTE = GND
M0, M1, M2, DCE/DTE = 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)
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
No-Cable Mode or Driver Disabled
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
MIN
– 7.5
– 5.5
– 4.5
TYP
– 9.6
– 8.5
– 6.5
– 6.0
500
2
MAX
UNITS
V
V
V
V
kHz
ms
V
f
OSC
t
r
V
IH
V
IL
I
IN
Charge Pump Oscillator Frequency
Charge Pump Rise Time
Logic Input High Voltage
Logic Input Low Voltage
Logic Input Current
Logic Inputs and Outputs
2.0
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
±
1
2
15
15
0
15
40
40
3
3
±100
25
65
65
12
±10
– 120
±10
V
µA
µA
µA
V
V
mA
µA
µA
V
V
V
V
V
V
mA
µA
ns
ns
ns
ns
ns
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 Rising
Input to Output Falling
Input to Output Difference,
t
PLH
– t
PHL
Output to Output Skew
q
q
q
q
q
(Figures 2, 13)
(Figures 2, 13)
(Figures 2, 13)
(Figures 2, 13)
(Figures 2, 13)
sn2847 2847fs
3
LTC2847
ELECTRICAL CHARACTERISTICS
SYMBOL
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
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
Output Voltage
Short-Circuit Current
Power-Off Resistance
Slew Rate
Input to Output
Input to Output
Differential Output Voltage
Single-Ended Output Voltage
Transmitter Output Offset
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
PARAMETER
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
V.11 Receiver
The
q
denotes specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
CC
= 5V, V
IN
= 3.3V, unless otherwise noted (Notes 2, 3)
CONDITIONS
– 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)
V
A
, V
B
= 0V
V
A
, V
B
= 0V
V
A
and
V
B
≤
0.25V
q
q
q
q
q
q
MIN
– 0.2
TYP
MAX
0.2
UNITS
V
mV
Ω
ns
15
100
103
15
50
50
0
4
40
90
90
25
±1.2
±0.66
±1.2
±0.6
ns
ns
ns
V
V
V
V
mA
mA
µA
Ω
Ω
ns
ns
ns
ns
ns
q
±0.44
q
q
q
q
q
q
±0.55
–9
9
50
135
– 11
11
±1
100
150
5
35
35
0
4
– 13
13
±100
150
165
65
65
16
– 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)
q
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
30
2.5
2.5
0.2
40
110
165
V
mV
Ω
Ω
ns
ns
ns
ns
V
V
mA
Ω
V/µs
µs
µs
sn2847 2847fs
q
q
q
q
q
q
q
±5
±8.5
4
LTC2847
ELECTRICAL CHARACTERISTICS
SYMBOL
PARAMETER
V.28 Receiver
V
THL
Input Low Threshold Voltage
V
TLH
Input High Threshold Voltage
∆V
TH
Receiver Input Hysteresis
R
IN
Receiver Input Impedance
t
r
, t
f
Rise or Fall Time
t
PLH
Input to Output
t
PHL
Input to Output
The
q
denotes specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
CC
= 5V, V
IN
= 3.3V, unless otherwise noted (Notes 2, 3)
CONDITIONS
(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
MIN
TYP
MAX
0.8
UNITS
V
V
V
kΩ
ns
ns
ns
2
0
3
0.05
5
15
60
160
0.3
7
300
300
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, V
IN
= 3.3V, C
VCC
= C
VIN
= 10µF,
C
VDD
= 1µF, C
VEE
= 3.3µF and T
A
= 25°C.
TYPICAL PERFOR A CE CHARACTERISTICS
V.11 Mode I
CC
vs Data Rate
170
160
150
140
140
T
A
= 25°C
I
CC
(mA)
I
CC
(mA)
I
CC
(mA)
130
120
110
100
90
10
100
1000
10000
2846 G04
DATA RATE (kBd)
V.11 Mode I
CC
vs Temperature
110
105
100
I
CC
(mA)
I
CC
(mA)
128.0
127.5
127.0
126.5
95
90
85
80
–40 –20
125.5
125.0
124.5
124.0
123.5
I
CC
(mA)
40
20
60
0
TEMPERATURE (°C)
U W
80
2846 G07
V.35 Mode I
CC
vs Data Rate
150
145
V.28 Mode I
CC
vs Data Rate
60
T
A
= 25°C
T
A
= 25°C
55
50
45
40
35
30
10
100
1000
DATA RATE (kBd)
10000
2846 G05
135
130
125
120
10
20
40
DATA RATE (kBd)
60
80 100
2846 G06
V.35 Mode I
CC
vs Temperature
37.5
37.0
36.5
36.0
35.5
35.0
34.5
34.0
40
20
0
60
TEMPERATURE (°C)
80
100
V.28 Mode I
CC
vs Temperature
126.0
100
123.0
–40 –20
33.5
–40 – 20
0
60
40
20
TEMPERATURE (°C)
80
100
3846 G09
2846 G08
sn2847 2847fs
5
