SP1481E/SP1485E
Enhanced Low Power Half-Duplex
RS-485 Transceivers
■ +5V Only
■ Low Power BiCMOS
■ Driver/Receiver Enable for Multi-Drop
configurations
■ Low Power Shutdown Mode
(SP48E)
■ Enhanced ESD Specifications:
+15KV Human Body Model
+15KV IEC1000-4-2 Air Discharge
+8KV IEC1000-4-2 Contact Discharge
RO 1
RE 2
DE 3
DI 4
R
8 V
CC
7 B
6 A
D
5 GND
description
The SP1481E and the SP1485E are a family of half-duplex transceivers that meet the
specifications of RS-485 and RS-422 serial protocols with enhanced ESD performance. The
ESD tolerance has been improved on these devices to over +15KV for both Human Body
Model and IEC1000-4-2 Air Discharge Method. These devices are pin-to-pin compatible
with Exar's SP481 and SP485 devices as well as popular industry standards. As with the
original versions, the SP1481E and the SP1485E feature Exar's BiCMOS design allowing
low power operation without sacrificing performance. The SP1481E and SP1485E meet the
requirements of the RS-485 and RS-422 protocols up to 20Mbps under load. The SP1481E
is equipped with a low power Shutdown mode.
Now Available in Lead Free Packaging
Exar Corporation 48720 Kato Road, Fremont CA, 94538 • 50-668-707 • www.exar.com
SP48E-485E_00_06609
ABsoLUte MAXiMUM rAtinGs
Output Voltages
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
Input Voltages
Logic...................................................-0.3V to (V
CC
+0.5V)
Drivers................................................-0.3V to (V
CC
+0.5V)
Receivers................................................................. ±15V
Logic.............................................-0.3V to (V
CC
+0.5V)
Drivers................................................................ ±15V
Receivers......................................-0.3V to (V
CC
+0.5V)
Storage Temperature.....................................................-65˚C to +150˚C
Power Dissipation per Package
8-pin NSOIC (derate 6.60mW/
o
C above +70
o
C).........................550mW
eLectricAL cHArActeristics
T
MIN
to T
MAX
and V
CC
= 5V ± 5% unless otherwise noted.
pArAMeters
sp1481e/sp1485e driver
dc characteristics
Differential Output Voltage
Differential Output Voltage
Differential Output Voltage
Change in Magnitude of Driver
Differential Output Voltage for
Complimentary States
Driver Common-Mode
Output Voltage
Input High Voltage
Input Low Voltage
Input Current
Driver Short-Circuit Current
V
OUT
= HIGH
V
OUT
= LOW
sp1481e/sp1485e driver
Ac characteristics
Maximum Data Rate
Driver Input to Output
Driver Input to Output
(SP1485EMN ONLY)
Driver Input to Output
Driver Input to Output
(SP1485EMN ONLY)
Driver Skew
Driver Rise or Fall Time
Driver Enable to Output High
Driver Enable to Output Low
Driver Disable Time from Low
Driver Disable Time from High
Min.
tYp.
MAX.
Units
conditions
3.5
2
1.5
2.0
V
CC
V
CC
V
CC
Volts
Volts
Volts
Unloaded; R = ∞; see Figure 1
with load; R = 50Ω; (RS-422);
see Figure 1
with load; R = 27Ω; (RS-485);see Figure 1
0.2
3
0.8
±10
±250
±250
Volts
Volts
Volts
Volts
μA
mA
mA
R = 27Ω or R = 50Ω; see Figure 1
R = 27Ω or R = 50Ω; see Figure 1
Applies to DE, DI, RE
Applies to DE, DI, RE
Applies to DE, DI, RE
-7V ≤ V
O
≤ +12V
-7V ≤ V
O
≤ +12V
20
20
20
20
20
3
8
40
40
40
40
30
40
30
40
5
20
70
70
70
70
Mbps
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
RE = 5V, DE = 5V; R
DIFF
= 54Ω,
C
L1
= C
L2
= 00pF
t
PLH
; R
DIFF
= 54Ω, C
L1
= C
L2
= 100pF;
see Figures 3 and 5
t
PLH
; R
DIFF
= 54Ω, C
LI
= C
L2
= 100pF;
See Figures 3 and 5
t
PHL
; R
DIFF
= 54Ω, C
L1
= C
L2
= 100pF;
see Figures 3 and 5
t
PHL
; R
DIFF
= 54Ω, C
L1
= C
L2
= 100pF;
see Figures 3 and 5
see Figures 3 and 5,
t
SKEW
= | t
PLH
- t
PHL
|
From 10% to 90%; R
DIFF
= 54Ω,
C
L1
= C
L2
= 100pF; see Figures 3 & 6
C
L
= 100pF; see Figures 4 & 6; S
2
closed
C
L
= 100pF; see Figures 4 & 6; S
closed
C
L
= 100pF; see Figures 4 & 6; S
closed
C
L
= 100pF; see Figures 4 & 6; S
2
closed
Exar Corporation 48720 Kato Road, Fremont CA, 94538 • 50-668-707 • www.exar.com
SP48E-485E_00_06609
2
T
MIN
to T
MAX
and V
CC
= 5V ± 5% unless otherwise noted
pArAMeters
sp1481e/sp1485e receiver
dc characteristics
Differential Input Threshold
Differential Input Threshold
(SP1485EMN ONLY)
Input Hysteresis
Output Voltage High
Output Voltage Low
Three-State (High Impedance)
Output Current
Input Resistance
Input Current (A, B); V
IN
= 12V
Input Current (A, B); V
IN
= -7V
12
15
±1
+1.0
-0.8
95
µA
kΩ
mA
mA
mA
0.4V ≤ V
O
≤ 2.4V; RE = 5V
-7V ≤ V
CM
≤ +12V
DE = 0V, V
CC
= 0V or 5.25V, V
IN
= 12V
DE = 0V, V
CC
= 0V or 5.25V, V
IN
= -7V
0V ≤ V
O
≤ V
CC
3.5
20
0.4
mV
Volts
Volts
V
CM
= 0V
I
O
= -4mA, V
ID
= +200mV
I
O
= +4mA, V
ID
= -200mV
-0.2
-0.4
+0.2
+0.4
Volts
Volts
-7V ≤ V
CM
≤ +12V
-7V ≤ V
CM
≤ +12V
Min.
tYp.
MAX.
Units
conditions
speciFicAtions (continued)
Short-Circuit Current 7
sp1481e/sp1485e receiver
Ac characteristics
Maximum Data Rate
Receiver Input to Output
Receiver Input to Output
Diff. Receiver Skew It
PLH
-t
PHL
I
Receiver Enable to
Output Low
Receiver Enable to
Output High
Receiver Disable from Low
sp1481e
shutdown timing
Time to Shutdown
Driver Enable from Shutdown
to Output High
Driver Enable from Shutdown
to Output Low
Receiver Enable from
Shutdown to Output High
Receiver Enable from
Shutdown to Output Low
poWer reQUireMents
Supply Voltage
Supply Current
SP1481E/1485E
No Load
SP48E
Shutdown Mode
environMentAL And MecHAnicAL
Operating Temperature
Commercial (_C_)
Industrial (_E_)
(_M_)
Storage Temperature
Package
NSOIC (_N)
0
-40
-40
-65
+4.75
50
20
25
25
5
45
45
45
70
70
10
70
70
70
70
Mbps
ns
ns
ns
ns
ns
ns
ns
RE = 0V, DE = 0V
t
PLH
; R
DIFF
= 54Ω,
C
L1
= C
L2
=
100pF; Figures 3 & 7
t
PHL
; R
DIFF
= 54Ω,
C
L1
= C
L2
=
100pF; Figures 3 & 7
R
DIFF
= 54Ω; C
L1
= C
L2
= 100pF;
Figures 3 & 7
C
RL
= 15pF; Figures 2 & 8; S
closed
C
RL
= 15pF; Figures 2 & 8; S
2
closed
C
RL
= 15pF; Figures 2 & 8; S
closed
C
RL
= 15pF; Figures 2 & 8; S
2
closed
Receiver Disable from High 45
200
40
40
300
300
900
600
600
100
100
1000
1000
+5.25
10
ns
ns
ns
ns
ns
Volts
μA
μA
μA
RE = 5V, DE = 0V
C
L
= 100pF; See Figures 4 & 6; S
2
closed
C
L
= 100pF; See Figures 4 & 6; S
closed
C
L
= 15pF; See Figures 2 & 8; S
2
closed
C
L
= 15pF; See Figures 2 & 8; S
closed
RE, DI = 0V or V
CC
; DE = V
CC
RE = 0V, DI = 0V or 5V; DE = 0V
DE = 0V, RE=V
CC
+70
+85
+125
+150
°C
°C
°C
°C
Exar Corporation 48720 Kato Road, Fremont CA, 94538 • 50-668-707 • www.exar.com
SP48E-485E_00_06609
3
pin FUnction
RO 1
RE 2
DE 3
DI 4
R
8
7
6
V
CC
B
A
GND
Pin 1 – RO – Receiver Output.
Pin 2 – RE – Receiver Output Enable Active LOW.
Pin 3 – DE – Driver Output Enable Active HIGH.
Pin 4 – DI – Driver Input.
Pin 5 – GND – Ground Connection.
D
SP485
Top View
5
Pin 6 – A – Driver Output/Receiver Input Non-inverting.
Pin 7 – B – Driver Output/Receiver Input Inverting.
Pin 8 – Vcc – Positive Supply 4.75V<Vcc< 5.25V.
SP48E and SP485E
Pinout (Top View)
A
R
V
OD
R
B
Figure 1. RS-485 Driver DC Test Load Circuit
3V
DE
DI
A
B
R
DIFF
C
L2
C
L1
A
B
RO
15pF
Receiver
Output
C
RL
Test Point
S
1
1K
S
2
1K
V
CC
V
OC
Figure 2. Receiver Timing Test Load Circuit
Output
Under
Test C
L
500
S
1
V
CC
S
2
Figure 3. RS-485 Driver/Receiver Timing Test Circuit
Figure 4. RS-485 Driver Timing Test Load #2 Circuit
DI
DRIVER
OUTPUT
+3V
0V
B
A
V
O
1/2V
O
f = 1MHz; t
R
< 1ns; t
F
< 1ns
1.5V
t
PLH
t
PHL
1.5V
t
PLH
1/2V
O
t
SKEW
t
SKEW
DIFFERENTIAL V
O
+
OUTPUT 0V
V
A
– V
B
V
O
–
Figure 5. Driver Propagation Delays
t
R
t
F
SP48E-485E_00_06609
Exar Corporation 48720 Kato Road, Fremont CA, 94538 • 50-668-707 • www.exar.com
4
INPUTS
LINE
DI CONDITION
1
0
X
X
No Fault
No Fault
X
Fault
OUTPUTS
B
0
1
Z
Z
A
1
0
Z
Z
INPUTS
RE
0
0
0
1
DE
0
0
0
0
A - B
+0.2V
-0.2V
Inputs Open
X
OUTPUTS
R
1
0
1
Z
RE DE
X
X
X
X
1
1
0
1
Table 2. Receive Function Truth Table
Table 1. Transmit Function Truth Table
f = 1MHz; f= t
R
< 1ns; t
F
< 1ns
DE
+3V
0V
5V
V
OL
V
OH
0V
1.5V
t
ZL
2.3V
Output normally LOW
Output normally HIGH
1.5V
t
LZ
0.5V
0.5V
t
HZ
A, B
A, B
2.3V
t
ZH
Figure 6. Driver Enable and Disable Times
A–B
V
0D2
+
V
0D2
–
V
OH
V
OL
t
PHL
0V
INPUT
1.5V
0V
R
t
PHL
f = 1MHz; t
R
< 1ns; t
F
< 1ns
OUTPUT
1.5V
Figure 7. Receiver Propagation Delays
RE
+3V
0V
5V
V
IL
V
IH
0V
f = 1MHz; t
R
< 1ns; t
F
< 1ns
1.5V
t
ZL
1.5V
Output normally LOW
Output normally HIGH
1.5V
t
LZ
0.5V
0.5V
t
HZ
R
R
1.5V
t
ZH
Figure 8. Receiver Enable and Disable Times
Exar Corporation 48720 Kato Road, Fremont CA, 94538 • 50-668-707 • www.exar.com
SP48E-485E_00_06609
5
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