®
SP481R/SP485R
1/10th Unit Load RS-485 Transceiver
FEATURES
■
Allows Over 400 Transceivers On A
Transmission Line (1/10th Unit Load)
■
High Impedance on Receiver Inputs
(R
IN
= 150kΩ typical)
■
Half-Duplex Configuration Consistent
With Industry Standard Pinout
■
–7V to +12V Common Mode Input
Voltage Range
■
Includes Shutdown Mode (I
CC
< 10µA)
(For SP481R Only)
■
Low Power Consumption (250mW)
■
Separate Driver and Receiver Enable
Now Available in Lead Free Packaging
DESCRIPTION
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 0.5µA typical.
TYPICAL APPLICATION CIRCUIT
RO 1
R
8
V
CC
RE 2
7
B
DE 3
6
A
D
DI 4
SP485
Top View
5
GND
Date: 6/21/04
SP485R RS-485 Serial Transceiver
© Copyright 2004 Sipex Corporation
1
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..........................-65˚C to +150˚C
Power Dissipation
8-pin Plastic DIP...........................1000mW
8-pin Plastic N-SOIC.......................1000mW
Package Derating:
8-pin Plastic DIP
ø
JA
....................................................62
°C/W
8-pin Plastic N-SOIC
ø
JA
....................................................62
°C/W
ELECTRICAL CHARACTERISTICS
Typically 25°C @ Vcc = +5V unless otherwise noted.
MIN.
LOGIC INPUTS
V
IL
V
IH
LOGIC OUTPUTS
V
OL
V
OH
RS-485 DRIVER
DC Characteristics
TTL Input Levels
V
IL
V
IH
Outputs
Open Circuit Voltage
Differential Output
Balance
Common-Mode Output
Output Current
Short Circuit Current
AC Characteristics
Maximum Data Rate
Output Transition Time
Propagation Delay
t
PHL
t
PLH
Driver Output Skew
RS-485 RECEIVER
DC Characteristics
TTL Output Levels
V
OL
V
OH
Tri-State Output Current
Inputs
Common Mode Range
Receiver Sensitivity
Input Impedance
TYP.
MAX.
0.8
UNITS
Volts
Volts
Volts
Volts
CONDITIONS
2.0
0.4
2.4
I
OUT
= -3.2mA
I
OUT
= 1.0mA
0.8
2.0
1.5
28.0
±250
5
30
60
60
5
100
100
15
6.0
5.0
±0.2
3.0
Volts
Volts
Volts
Volts
Volts
Volts
mA
mA
Mbps
ns
ns
ns
ns
R
L
=54Ω, C
L
=50pF
|V
T
| - |V
T
|
R
L
=54Ω
Terminated in –7V to +12V
R
L
=54Ω
Rise/fall time, 10%–90%
See Figures 3 and 5
R
DIFF
=54Ω, C
L1
=C
L2
=100pF
R
DIFF
=54Ω, C
L1
=C
L2
=100pF
see Figure 3 and 5,
t
SKEW
= | t
DPLH
- t
DPHL
|
0.4
2.4
±1
–7.0
120
150
+12.0
±0.2
Volts
Volts
µA
Volts
Volts
kΩ
0.4V≤V
OUT
≤2.4V;
RE = V
CC
–7V
≤
V
CM
≤
+12V
–7V
≤
V
CM
≤
+12V
Date: 6/21/04
SP485R RS-485 Serial Transceiver
© Copyright 2004 Sipex Corporation
2
ELECTRICAL CHARACTERISTICS
Typically 25°C @ Vcc = +5V unless otherwise noted.
MIN.
AC Characteristics
Maximum Data Rate
Propagation Delay
t
PHL
t
PLH
Differential Receiver Skew
TYP.
MAX.
UNITS
CONDITIONS
1
1200
1200
60
Mbps
ns
ns
ns
See Figures 3 and 7
R
DIFF
=54Ω, C
L1
=C
L2
=100pF
R
DIFF
=54Ω, C
L1
=C
L2
=100pF
| t
PLH
– t
PHL
|; R
DIFF
=54Ω,
C
L1
=C
L2
=100pF, see Figures 3 and 7
SHUTDOWN TIMING (SP481R)
Time to Shutdown
50
RS-485 Driver
Enable Time
Enable to Low
Enable to High
Disable Time
Disable From Low
Disable From High
RS-485 Receiver
Enable Time
Enable to Low
Enable to High
Disable Time
Disable From Low
Disable From High
POWER REQUIREMENTS
Supply Voltage V
CC
Supply Current I
CC
No Load
No Load
Supply Current in Shutdown
ENVIRONMENTAL
Operating Temperature
Commercial (..C..)
Industrial (..E..)
Storage Temperature
600
40
40
40
40
40
40
40
40
500
500
500
500
500
500
500
500
ns
ns
ns
ns
ns
ns
ns
ns
ns
RE = V
CC
, DE = 0V
See Figures 4 and 6
C
L
=15pF, S
1
Closed
C
L
=15pF, S
2
Closed
See Figures 4 and 6
C
L
=15pF, S
1
Closed
C
L
=15pF, S
2
Closed
See Figures 2 and 8
C
L
=15pF, S
1
Closed
C
L
=15pF, S
2
Closed
See Figures 2 and 8
C
L
=15pF, S
1
Closed
C
L
=15pF, S
2
Closed
+4.75
300
500
0.5
+5.25
500
900
10
Volts
µA
µA
µA
RE = V
CC
or 0V, DE = 0V
RE = V
CC
or 0V, DE = V
CC
RE = V
CC
, DE = OV
0
–40
–65
+70
+85
+150
°C
°C
°C
RECEIVER INPUT GRAPH
Standard SP485R Reciever
+1.0mA
SP485R Reciever
+100µA
-7V
-3V
-7V
-3V
+6V
-0.6 mA
+12V
+6V
-60µA
+12V
1 Unit Load
Maximum Input Current
versus voltage.
(Shaded region)
1/10 Unit Load
Maximum Input Current
versus voltage.
(Shaded region)
Date: 6/21/04
SP485R RS-485 Serial Transceiver
© Copyright 2004 Sipex Corporation
3
TEST CIRCUITS
A
R
V
OD
R
B
Figure 1. Driver DC Test Load Circuit
Figure 2. Receiver Timing Test Load Circuit
Receiver
Output
C
RL
Test Point
S
1
1kΩ
S
2
1kΩ
V
CC
V
OC
C
L1
DI
A
B
C
L2
R
L
A
RO
B
15pF
Output
Under
Test
500Ω
C
L
S
1
V
CC
S
2
Figure 3. Driver/Receiver Timing Test Circuit
Figure 4. Driver Timing Test Load #2 Circuit
SWITCHING WAVEFORMS
+3V
DI
0V
DRIVER
OUTPUT
B
A
f = 1MHz; t
R
< 10ns; t
F
< 10ns
1.5V
t
PLH
V
O
1/2V
O
t
DPLH
t
DPHL
t
PHL
1.5V
t
PLH
1/2V
O
DIFFERENTIAL V
O
+
OUTPUT 0V
V
A
– V
B
V
O
–
t
SKEW
= | t
DPLH
- t
DPHL
|
t
R
t
F
Figure 5. Driver Propagation Delays
Date: 6/21/04
SP485R RS-485 Serial Transceiver
© Copyright 2004 Sipex Corporation
4
+3V
DE
0V
5V
A, B
V
OL
V
OH
A, B
0V
f = 1MHz; t
R
< 10ns; t
F
< 10ns
1.5V
t
ZL
2.3V
Output normally LOW
1.5V
t
LZ
0.5V
0.5V
t
HZ
2.3V
t
ZH
Output normally HIGH
Figure 6. Driver Enable and Disable Times
f = 1MHz; t
R
< 10ns; t
F
< 10ns
V
0D2
+
A–B
V
0D2
–
V
OH
RECEIVER OUT
V
OL
t
PHL
1.5V
0V
INPUT
0V
OUTPUT
t
PLH
1.5V
t
SKEW
= | t
PHL
- t
PLH
|
Figure 7. Receiver Propagation Delays
+3V
RE
0V
5V
RECEIVER OUT
V
IL
V
IH
RECEIVER OUT
0V
1.5V f = 1MHz; t < 10ns; t < 10ns
R
F
t
ZL
1.5V
Output normally LOW
1.5V
t
LZ
0.5V
0.5V
t
HZ
1.5V
t
ZH
Output normally HIGH
Figure 8. Receiver Enable and Disable Times
Date: 6/21/04
SP485R RS-485 Serial Transceiver
© Copyright 2004 Sipex Corporation
5
Analog electronics
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