®
PRELIMINARY
SP1485E
Enhanced Low Power Half-Duplex
RS-485 Transceivers
■
+5V supply
■
Low Power BiCMOS
■
Driver/Receiver Enable for Multi-Drop
configurations
■
Available in 8 Pin NSOIC or PDIP
packages
■
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
8
VCC
SP1485E
8 Pin - nSOIC
7
B
6
A
5
GND
DESCRIPTION
The
SP1485E
is a half-duplex transceiver that meets the specifications of RS-485 and RS-
422 serial protocols with enhanced ESD performance. The ESD tolerance has been improved
on this device to over +15KV for both Human Body Model and IEC1000-4-2 Air Discharge
Method. This device is pin-to-pin compatible with Sipex's SP485 devices as well as popular
industry standards. As with the original version, the
SP1485E
features Sipex's BiCMOS
design allowing low power operation without sacrificing performance. The
SP1485E
meets
the requirements of the RS-485 and RS-422 protocols up to 20Mbps under load.
BLOCK DIAGRAM
RO 1
RE 2
DE 3
DI 4
R
8 Vcc
7B
6A
D
SP1485E
5 GND
Rev:C Date: 02/26/04
SP1485E Low Power Half-Duplex RS485 Transceivers
© 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
Input Voltages
Logic........................................................-0.3V to (V
CC
+0.5V)
Drivers..................................................-0.3V to (V
CC
+0.5V)
Receivers.................................................................
±15V
Output Voltages
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
8-pin PDIP (derate 11.8mW/
o
C above +70
o
C)............................1000mW
ELECTRICAL CHARACTERISTICS
T
MIN
to T
MAX
and V
CC
= 5V
±
5% unless otherwise noted.
PARAMETERS
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
SP1485E DRIVER
AC Characteristics
Maximum Data Rate
Driver Input to Output
MIN.
TYP.
MAX.
UNITS
CONDITIONS
3.5
2
1.5
V
CC
V
CC
V
CC
0.2
3
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
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
2.0
0.8
±10
±250
±250
20
10
10
30
40
Mbps
ns
ns
3
8
40
40
40
40
20
70
70
70
70
ns
ns
ns
ns
ns
ns
RE = 5V, DE = 5V; R
DIFF
= 54Ω,
C
L1
= C
L2
= 100pF
t
PLH
; R
DIFF
= 54Ω, C
L1
= C
L2
= 100pF;
see Figures 3 and 5
t
PHL
; R
DIFF
= 54Ω, C
LI
= C
L2
= 100pF;
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
see Figures 3 and 5,
t
SKEW
= | t
DPLH
- t
DPHL
|
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
1
closed
C
L
= 100pF;
see Figures 4 & 6;
S
1
closed
C
L
= 100pF;
see Figures 4 & 6;
S
2
closed
Rev:C Date: 02/26/04
SP1485E Low Power Half-Duplex RS485 Transceivers
© Copyright 2004 Sipex Corporation
2
SPECIFICATIONS
(continued)
T
MIN
to T
MAX
and V
CC
= 5V
±
5% unless otherwise noted.
PARAMETERS
MIN.
SP1485E RECEIVER
DC Characteristics
Differential Input Threshold
-0.2
Differential Input Threshold
-0.4
(SP1485EMN ONLY)
Input Hysteresis
Output Voltage High
3.5
Output Voltage Low
Three-State (High Impedance)
Output Current
Input Resistance
12
Input Current (A, B); V
IN
= 12V
Input Current (A, B); V
IN
= -7V
Short-Circuit Current
7
SP1485E RECEIVER
AC Characteristics
Maximum Data Rate
20
Receiver Input to Output
15
15
Diff. Receiver Skew It
PLH
-t
PHL
I
Receiver Enable to
Output Low
Receiver Enable to
Output High
Receiver Disable from Low
Receiver Disable from High
TYP.
MAX.
UNITS
CONDITIONS
+0.2
+0.4
20
0.4
±1
15
+1.0
-0.8
95
Volts
Volts
mV
Volts
Volts
µA
kΩ
mA
mA
mA
-7V
≤
V
CM
≤
+12V
-7V
≤
V
CM
≤
+12V
V
CM
= 0V
I
O
= -4mA, V
ID
= +200mV
I
O
= +4mA, V
ID
= -200mV
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
RE = 0V, DE = 0V
t
PLH
; R
DIFF
= 54Ω,
C
L1
= C
L2
= 100pF;
Figures 3 & 7
t
PHL
; R
DIFF
= 54Ω, C
LI
= C
L2
= 100pF
R
DIFF
= 54Ω; C
L1
= C
L2
= 100pF;
Figures 3 & 7
C
RL
= 15pF;
Figures 2 & 8;
S
1
closed
C
RL
= 15pF;
Figures 2 & 8;
S
2
closed
C
RL
= 15pF;
Figures 2 & 8;
S
1
closed
C
RL
= 15pF;
Figures 2 & 8;
S
2
closed
40
50
Mbps
ns
ns
ns
5
10
45
45
45
45
70
70
70
70
ns
ns
ns
ns
POWER REQUIREMENTS
Supply Voltage
Supply Current
SP1485E
No Load
+4.75
+5.25
Volts
900
600
µA
µA
RE, DI = 0V or V
CC
; DE = V
CC
RE = 0V, DI = 0V or 5V; DE = 0V
ENVIRONMENTAL
AND MECHANICAL
Operating Temperature
Commercial (_C_)
Industrial (_E_)
(_M_)
Storage Temperature
Package
Plastic DIP (_P)
NSOIC (_N)
0
-40
-40
-65
+70
+85
+125
+150
°C
°C
°C
°C
Rev:C Date: 02/26/04
SP1485E Low Power Half-Duplex RS485 Transceivers
© Copyright 2004 Sipex Corporation
3
PIN FUNCTION
RO 1
R
8
V
CC
Pin 1 – RO – Receiver Output.
Pin 2 – RE – Receiver Output Enable Active LOW.
RE 2
7
B
Pin 3 – DE – Driver Output Enable Active HIGH.
Pin 4 – DI – Driver Input.
Pin 5 – GND – Ground Connection.
DE 3
6
A
D
DI 4
SP485
Top View
5
GND
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.
SP1485E
Pinout (Top View)
A
R
V
OD
R
B
Figure 1. RS-485 Driver DC Test Load Circuit
V
OC
Receiver
Output
Test Point
C
RL
1k
S
1
1k
V
CC
S
2
Figure 2. Receiver Timing Test Load Circuit
DI
A
B
C
L1
R
DIFF
C
L2
A
B
RO
15pF
Output
Under C
L
Test
500
S
1
V
CC
S
2
Figure 4. RS-485 Driver Timing Test Load #2 Circuit
Figure 3. RS-485 Driver/Receiver Timing Test Circuit
+3V
DI
0V
DRIVER
OUTPUT
B
A
V
O
1/2V
O
f = 1MHz; t
R
< 1.0ns; t
F
< 1.0ns
1.5V
t
PLH
t
PHL
1/2V
O
t
DPLH
t
DPHL
1.5V
DIFFERENTIAL V
O
+
OUTPUT 0V
V
A
– V
B
V
O
–
t
SKEW =
| t
DPLH -
t
DPHL
|
Figure 5. Driver Propagation Delays
Rev:C Date: 02/26/04
t
R
t
F
SP1485E Low Power Half-Duplex RS485 Transceivers
© Copyright 2004 Sipex Corporation
4
INPUTS
RE
X
X
X
X
DE
1
1
0
1
DI
1
0
X
X
LINE
CONDITION
No Fault
No Fault
X
Fault
OUTPUTS
B
0
1
Z
Z
A
1
0
Z
Z
INPUTS
RE
DE
0
0
0
0
0
0
1
0
OUTPUTS
A-B
R
+0.2V
1
-0.2V
0
Inputs Open
1
X
Z
Table 2. Receive Function Truth Table
Table 1. Transmit Function Truth Table
+3V
DE
0V
5V
A, B
V
OL
V
OH
A, B
0V
Figure 6. Driver Enable and Disable Times
f = 1MHz; t
R
< 1.0ns; t
F
< 1.0ns
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
V
0D2
+
A–B
V
0D2
–
V
OH
R
V
OL
t
PHL
0V
INPUT
0V
1.5V
OUTPUT
1.5V
t
PLH
f = 1MHz; t
R
< 1.0ns; t
F
< 1.0ns
t
SKEW =
| t
PHL -
t
PLH
|
Figure 7. Receiver Propagation Delays
+3V
RE
0V
5V
R
V
IL
V
IH
R
0V
1.5V
t
ZH
Output normally HIGH
1.5V
Output normally LOW
0.5V
0.5V
t
HZ
1.5V
f = 1MHz; t
R
< 1.0ns; t
F
< 1.0ns
t
ZL
1.5V
t
LZ
Figure 8. Receiver Enable and Disable Times
Rev:C Date: 02/26/04
SP1485E Low Power Half-Duplex RS485 Transceivers
© Copyright 2004 Sipex Corporation
5
Embedded System
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