Date: 6/21/04
SP485R RS-485 Serial Transceiver
Copyright 2004 Sipex Corporation
1
FEATURES
Allows Over 400 Transceivers On A
Transmission Line (1/10th Unit Load)
High Impedance on Receiver Inputs
(R
IN
= 150k
typical)
Half-Duplex Configuration Consistent
With Industry Standard Pinout
7V to +12V Common Mode Input
Voltage Range
Includes Shutdown Mode (I
CC
< 10
A)
(For SP481R Only)
Low Power Consumption (250mW)
Separate Driver and Receiver Enable
The SP481R and SP485R are pin-to-pin equivalent with our existing SP485 product and contain
enhancements such as higher ESD tolerance and high receiver input impedance. The higher
receiver input impedance allows for connecting over 400 transceivers on a single transmission
line without degrading the RS-485 driver signal. Each device is packaged in an 8-pin plastic DIP
or 8-pin narrow SOIC package. The SP481R offers a shutdown feature via the enable pins which
will reduce the supply current (I
CC
) below 0.5
A typical.
RO 1
RE 2
DE 3
DI 4
8 V
CC
7 B
6 A
5 GND
D
R
SP485
Top View
SP481R/SP485R
1/10th Unit Load RS-485 Transceiver
Now Available in Lead Free Packaging
DESCRIPTION
TYPICAL APPLICATION CIRCUIT
Date: 6/21/04
SP485R RS-485 Serial Transceiver
Copyright 2004 Sipex Corporation
2
Typically 25
C @ Vcc = +5V unless otherwise noted.
MIN.
TYP.
MAX.
UNITS
CONDITIONS
LOGIC INPUTS
V
IL
0.8
Volts
V
IH
2.0
Volts
LOGIC OUTPUTS
V
OL
0.4
Volts
I
OUT
= -3.2mA
V
OH
2.4
Volts
I
OUT
= 1.0mA
RS-485 DRIVER
DC Characteristics
TTL Input Levels
V
IL
0.8
Volts
V
IH
2.0
Volts
Outputs
Open Circuit Voltage
6.0
Volts
Differential Output
1.5
5.0
Volts
R
L
=54
, C
L
=50pF
Balance
0.2
Volts
|V
T
| - |V
T
|
Common-Mode Output
3.0
Volts
Output Current
28.0
mA
R
L
=54
Short Circuit Current
250
mA
Terminated in 7V to +12V
AC Characteristics
Maximum Data Rate
5
Mbps
R
L
=54
Output Transition Time
30
ns
Rise/fall time, 10%90%
Propagation Delay
See Figures 3 and 5
t
PHL
60
100
ns
R
DIFF
=54
, C
L1
=C
L2
=100pF
t
PLH
60
100
ns
R
DIFF
=54
, C
L1
=C
L2
=100pF
Driver Output Skew
5
15
ns
see Figure 3 and 5,
t
SKEW
= | t
DPLH
- t
DPHL
|
RS-485 RECEIVER
DC Characteristics
TTL Output Levels
V
OL
0.4
Volts
V
OH
2.4
Volts
Tri-State Output Current
1
A
0.4V
V
OUT
2.4V; RE = V
CC
Inputs
Common Mode Range
7.0
+12.0
Volts
Receiver Sensitivity
0.2
Volts
7V
V
CM
+12V
Input Impedance
120
150
k
7V
V
CM
+12V
ABSOLUTE MAXIMUM RATINGS
These are stress ratings only and functional operation
of the device at these ratings or any other above those
indicated in the operation sections of the specifications
below is not implied. Exposure to absolute maximum
rating conditions for extended periods of time may
affect reliability.
V
CC
...........................................................................+7V
Storage Temperature..........................-65C to +150C
Power Dissipation
8-pin Plastic DIP...........................1000mW
8-pin Plastic N-SOIC.......................1000mW
Package Derating:
8-pin Plastic DIP
JA
....................................................62
C/W
8-pin Plastic N-SOIC
JA
....................................................62
C/W
ELECTRICAL CHARACTERISTICS
Date: 6/21/04
SP485R RS-485 Serial Transceiver
Copyright 2004 Sipex Corporation
3
RECEIVER INPUT GRAPH
Typically 25
C @ Vcc = +5V unless otherwise noted.
MIN.
TYP.
MAX.
UNITS
CONDITIONS
AC Characteristics
Maximum Data Rate
1
Mbps
Propagation Delay
See Figures 3 and 7
t
PHL
1200
ns
R
DIFF
=54
, C
L1
=C
L2
=100pF
t
PLH
1200
ns
R
DIFF
=54
, C
L1
=C
L2
=100pF
Differential Receiver Skew
60
ns
| t
PLH
t
PHL
|; R
DIFF
=54
,
C
L1
=C
L2
=100pF, see Figures 3 and 7
SHUTDOWN TIMING (SP481R)
Time to Shutdown
50
600
ns
RE = V
CC
, DE = 0V
RS-485 Driver
Enable Time
See Figures 4 and 6
Enable to Low
40
500
ns
C
L
=15pF, S
1
Closed
Enable to High
40
500
ns
C
L
=15pF, S
2
Closed
Disable Time
See Figures 4 and 6
Disable From Low
40
500
ns
C
L
=15pF, S
1
Closed
Disable From High
40
500
ns
C
L
=15pF, S
2
Closed
RS-485 Receiver
Enable Time
See Figures 2 and 8
Enable to Low
40
500
ns
C
L
=15pF, S
1
Closed
Enable to High
40
500
ns
C
L
=15pF, S
2
Closed
Disable Time
See Figures 2 and 8
Disable From Low
40
500
ns
C
L
=15pF, S
1
Closed
Disable From High
40
500
ns
C
L
=15pF, S
2
Closed
POWER REQUIREMENTS
Supply Voltage V
CC
+4.75
+5.25
Volts
Supply Current I
CC
No Load
300
500
A
RE = V
CC
or 0V, DE = 0V
No Load
500
900
A
RE = V
CC
or 0V, DE = V
CC
Supply Current in Shutdown
0.5
10
A
RE = V
CC
, DE = OV
ENVIRONMENTAL
Operating Temperature
Commercial (..C..)
0
+70
C
Industrial (..E..)
40
+85
C
Storage Temperature
65
+150
C
ELECTRICAL CHARACTERISTICS
-7V
-3V
+6V
+12V
-60
A
+100
A
1/10 Unit Load
Maximum Input Current
versus voltage.
(Shaded region)
SP485R Reciever
-7V
-3V
+6V
+12V
-0.6 mA
+1.0mA
1 Unit Load
Maximum Input Current
versus voltage.
(Shaded region)
Standard SP485R Reciever
Date: 6/21/04
SP485R RS-485 Serial Transceiver
Copyright 2004 Sipex Corporation
4
Figure 5. Driver Propagation Delays
Figure 3. Driver/Receiver Timing Test Circuit
Figure 4. Driver Timing Test Load #2 Circuit
Figure 1. Driver DC Test Load Circuit
Figure 2. Receiver Timing Test Load Circuit
C
L1
15pF
RO
A
B
A
B
DI
C
L2
R
L
A
B
R
R
V
OD
V
OC
500
C
L
Output
Under
Test
S
1
S
2
V
CC
1k
1k
C
RL
Receiver
Output
S
1
S
2
Test Point
V
CC
TEST CIRCUITS
SWITCHING WAVEFORMS
+3V
+3V
0V
0V
DI
DI
B
A
DRIVER
DRIVER
OUTPUT
OUTPUT
V
O
+
DIFFERENTIAL
DIFFERENTIAL
OUTPUT
OUTPUT
V
A
V
V
B
0V
0V
V
O
1.5V
1.5V
1.5V
1.5V
t
PLH
PLH
t
R
t
F
f = 1MHz; t
f = 1MHz; t
R
< 10ns; t
< 10ns; t
F
< 10ns
< 10ns
V
O
1/2V
1/2V
O
1/2V
1/2V
O
t
PHL
PHL
t
SKEW
SKEW
= |
= | t
DPLH
DPLH
- t
DPHL
DPHL
|
t
DPLH
DPLH
t
DPHL
DPHL
t
PLH
PLH
Date: 6/21/04
SP485R RS-485 Serial Transceiver
Copyright 2004 Sipex Corporation
5
Figure 6. Driver Enable and Disable Times
Figure 7. Receiver Propagation Delays
V
OH
V
OL
RECEIVER OUT
1.5V
1.5V
t
PHL
f = 1MHz; t
R
< 10ns; t
F
< 10ns
OUTPUT
V
0D2
+
V
0D2
A B
0V
0V
t
PLH
INPUT
t
SKEW
= | t
PHL
- t
PLH
|
Figure 8. Receiver Enable and Disable Times
+3V
0V
DE
5V
V
OL
A, B
0V
1.5V
1.5V
t
ZL
t
ZH
f = 1MHz; t
R
< 10ns; t
F
< 10ns
V
OH
A, B
2.3V
2.3V
t
LZ
t
HZ
0.5V
0.5V
Output normally LOW
Output normally HIGH
+3V
0V
RE
5V
0V
1.5V
1.5V
t
ZL
t
ZH
f = 1MHz; t
R
< 10ns; t
F
< 10ns
RECEIVER OUT
1.5V
1.5V
t
LZ
t
HZ
0.5V
0.5V
Output normally LOW
Output normally HIGH
V
IL
V
IH
RECEIVER OUT
Date: 6/21/04
SP485R RS-485 Serial Transceiver
Copyright 2004 Sipex Corporation
6
with the two 125
cable termination resistors
on each end.
The receiver contains a enable pin (RE) which
enables the receiver when a logic LOW is
asserted. A logic HIGH will tri-state the
receiver output and the inputs will maintain
at least 120k
impedance. The receiver can
operate to at least 1Mbps.
The receiver also contains a fail-safe feature
which outputs a logic HIGH when the inputs are
open as in a disconnected cable.
SHUTDOWN MODE
The SP481R includes a shutdown function to
reduce power consumption. The shutdown is
activated by simultaneously applying a logic
LOW to DE and a logic HIGH to RE. While in
the shutdown mode, the power supply current is
typically less than 1
A. The driver outputs are
disabled and are at a high impedance state
determined by the receiver input impedance
which should be at least 120k
. The receiver
output is at also at high impedance during
shutdow. Output leakage current when the
receiver is disabled is under 1
A.
GENERAL DESCRIPTION
The SP485R is a low power RS-485 differential
transceiver. Similar to the SP485, the SP485R
contains a half-duplex driver and receiver with
tri-state control. However, the SP485R is in-
tended for increased connections on a single bus
compared to the orignal RS-485 specification.
The RS-485 standard is ideal for multi-drop
applications where one bus can contain many
drivers and/or receivers. The RS-485 standard
implementation allows up to 32 transceivers to
be connected on to the data bus. RS-485 is also
specified for driving higher speeds over long
cable lengths of up to 4,000 feet. The SP485R
and SP481R exceed the standard b allowing up
to 400 receivers to share a bus.
DRIVERS
The driver output complies with the RS-485
electrical characteristics as specified by the
standard. The output swings from 0V to V
CC
and
maintains greater than +1.5V with a 54
load
attached between the two outputs. In adhering
to the RS-485 specification, the driver outputs
inherently comply with the RS-422 standard.
With a load of 100
between the two outputs,
the driver can sustain at least +2.0V.
The driver contains an enable pin (DE) which
tri-states the output when DE is a logic LOW.
The outputs during the tri-stated condition are
at a high impedance (>100k
). A logic HIGH
enables the driver for normal operation. The
driver can operate to at least 5Mbps.
RECEIVERS
The SP485R receiver has differential inputs
with an input sensitivity of lower than
200mV.
As mentioned above, the RS-485 specification
allows up to 32 transceivers on a the same bus.
The SP485R allows over 400 transceivers on
the same bus due to the high input impedance of
at least 120k
. This higher capacity allows
more components to be attached to the same
bus without degrading the signal quality. The
drivers are still able to drive an equivalent 54
from the 320 transceivers with an input
impedance of at least 120k
in parallel along
Date: 6/21/04
SP485R RS-485 Serial Transceiver
Copyright 2004 Sipex Corporation
7
PACKAGE: 8 PIN PDIP
INDEX
AREA
b
N
1
2
3
N/2
c
- - .210
.015
-
Dimensions in inches
8 PIN PDIP
JEDEC MS-001
(BA) Variation
.115 .130 .195
.014 .018 .022
.045 .060 .070
.240 .250 .280
A
A1
A2
b
c
D1
E
E1
e
eA
eB
.115 .130 .150
L
MIN NOM MAX
b2
b3
.030 .039 .045
D
.008
.010
.014
.355
.365
.400
.005
.300
.310
.325
.100 BSC
.300 BSC
.430
-
-
-
-
-
D1
eA
eB
E
c
8 PIN PDIP
E
E1
D
A
L
A2
A1
b
b2
e
b3
Date: 6/21/04
SP485R RS-485 Serial Transceiver
Copyright 2004 Sipex Corporation
8
PACKAGE: 8 PIN NSOIC
SEE VIEW C
1
1.65
DIMENSIONS
Minimum/Maximum
(mm)
8 Pin NSOIC
(JEDEC MS-012,
AA - VARIATION)
COMMON HEIGHT DIMENSION
A
A1
A2
b
c
L
e
E1
E
L2
L1
1.35
4.90 BSC
0.40
0.31
0.51
SYMBOL
MIN NOM MAX
0.10
-
0.25
D
1.75
1.25
0.17
0.25
6.00 BSC
3.90 BSC
1.27 BSC
1.27
1.04 REF
0.25 BSC
0
5
8
15
-
-
-
-
-
-
-
A
A2
A1
SEATING PLANE
SIDE VIEW
L1
L
1
1
Seating Plane
Gauge Plane
L2
VIEW C
TOP VIEW
e
E
E/2
E1
A
INDEX AREA
(D/2 X E1/2)
E1/2
D
b
1
8 PIN NSOIC
PACKAGE:
c
WITH PLATING
BASE METAL
b
CONTACT AREA
Date: 6/21/04
SP485R RS-485 Serial Transceiver
Copyright 2004 Sipex Corporation
9
Part Number
Temperature Range
Package Types
SP481RCP ........................................................................ 0
C to +70
C ................................................................................................ 8 Pin PDIP
SP481RCN ........................................................................ 0
C to +70
C ............................................................................................. 8 Pin NSOIC
SP481RCN/TR .................................................................. 0
C to +70
C ............................................................................................. 8 Pin NSOIC
SP481REP ..................................................................... -40
C to +85
C ................................................................................................ 8 Pin PDIP
SP481REN ..................................................................... -40
C to +85
C ............................................................................................. 8 Pin NSOIC
SP481REN/TR ............................................................... -40
C to +85
C ............................................................................................. 8 Pin NSOIC
SP485RCP ........................................................................ 0
C to +70
C ................................................................................................ 8 Pin PDIP
SP485RCN ........................................................................ 0
C to +70
C ................................................................................................ 8 Pin NOIC
SP485RCN/TR .................................................................. 0
C to +70
C ................................................................................................ 8 Pin NOIC
SP485REP ..................................................................... -40
C to +85
C ................................................................................................ 8 Pin PDIP
SP485REN ..................................................................... -40
C to +85
C ................................................................................................ 8 Pin NOIC
SP485REN/TR ............................................................... -40
C to +85
C ................................................................................................ 8 Pin NOIC
Sipex Corporation reserves the right to make changes to any products described herein. Sipex does not assume any liability arising out of the
application or use of any product or circuit described herein; neither does it convey any license under its patent rights nor the rights of others.
Corporation
ANALOG EXCELLENCE
Available in lead free packaging. To order add "-L" suffix to part number.
Example: SP485REN/TR = standard; SP485REN-L/TR = lead free
/TR = Tape and Reel
Pack quantity is 2,500 for NSOIC.
Sipex Corporation
Headquarters and
Sales Office
233 South Hillview Drive
Milpitas, CA 95035
TEL: (408) 934-7500
FAX: (408) 935-7600
ORDERING INFORMATION
DATE
REVISION
DESCRIPTION
6/21/04
A
Added extended temp range and tape and reel part numbers. Updated
packaging specs.
REVISION HISTORY
PDF 
ZIP