Low-Power, Slew-Rate-Limited
RS-485/RS-422 Transceivers
General Description
The HWD481, HWD483, HWD485, HWD487–HWD491, and
HWD1487 are low-power transceivers for RS-485 and RS-
422 communication. Each part contains one driver and one
receiver. The HWD483, HWD487, HWD488, and HWD489
feature reduced slew-rate drivers that minimize EMI and
reduce reflections caused by improperly terminated cables,
thus allowing error-free data transmission up to 250kbps.
The driver slew rates of the HWD481, HWD485, HWD490,
HWD491, and HWD1487 are not limited, allowing them to
transmit up to 2.5Mbps.
These transceivers draw between 120µA and 500µA of
supply current when unloaded or fully loaded with disabled
drivers. Additionally, the HWD481, HWD483, and HWD487
have a low-current shutdown mode in which they consume
only 0.1µA. All parts operate from a single 5V supply.
Drivers are short-circuit current limited and are protected
against excessive power dissipation by thermal shutdown
circuitry that places the driver outputs into a high-imped-
ance state. The receiver input has a fail-safe feature that
guarantees a logic-high output if the input is open circuit.
The HWD487 and HWD1487 feature quarter-unit-load
receiver input impedance, allowing up to 128 HWD487/
HWD1487 transceivers on the bus. Full-duplex communi-
cations are obtained using the HWD488–HWD491, while
the HWD481, HWD483, HWD485, HWD487, and HWD1487
are designed for half-duplex applications.
__Next Generation Device Features
♦
For Fault-Tolerant Applications
HWD3430:
±80V Fault-Protected, Fail-Safe, 1/4
Unit Load, +3.3V, RS-485 Transceiver
HWD3440E–HWD3444E:
±15kV ESD-Protected,
±60V Fault-Protected, 10Mbps, Fail-Safe,
RS-485/J1708 Transceivers
♦
For Space-Constrained Applications
HWD3460–HWD3464:
+5V, Fail-Safe, 20Mbps,
Profibus RS-485/RS-422 Transceivers
HWD3362:
+3.3V, High-Speed, RS-485/RS-422
Transceiver in a SOT23 Package
HWD3280E–HWD3284E:
±15kV ESD-Protected,
52Mbps, +3V to +5.5V, SOT23, RS-485/RS-422,
True Fail-Safe Receivers
HWD3293/HWD3294/HWD3295:
20Mbps, +3.3V,
SOT23, RS-855/RS-422 Transmitters
♦
For Multiple Transceiver Applications
HWD3030E–HWD3033E:
±15kV ESD-Protected,
+3.3V, Quad RS-422 Transmitters
♦
For Fail-Safe Applications
HWD3080–HWD3089:
Fail-Safe, High-Speed
(10Mbps), Slew-Rate-Limited RS-485/RS-422
Transceivers
♦
For Low-Voltage Applications
HWD3483E/HWD3485E/HWD3486E/HWD3488E/
HWD3490E/HWD3491E:
+3.3V Powered, ±15kV
ESD-Protected, 12Mbps, Slew-Rate-Limited,
True RS-485/RS-422 Transceivers
Ordering Information appears at end of data sheet.
________________________Applications
Low-Power RS-485 Transceivers
Low-Power RS-422 Transceivers
Level Translators
Transceivers for EMI-Sensitive Applications
Industrial-Control Local Area Networks
______________________________________________________________Selection Table
PART
NUMBER
HWD481
HWD483
HWD485
HWD487
HWD488
HWD489
HWD490
HWD491
HWD1487
HALF/FULL
DUPLEX
Half
Half
Half
Half
Full
Full
Full
Full
Half
DATA RATE
(Mbps)
2.5
0.25
2.5
0.25
0.25
0.25
2.5
2.5
2.5
SLEW-RATE
LIMITED
No
Yes
No
Yes
Yes
Yes
No
No
No
LOW-POWER
SHUTDOWN
Yes
Yes
No
Yes
No
No
No
No
No
RECEIVER/
DRIVER
ENABLE
Yes
Yes
Yes
Yes
No
Yes
No
Yes
Yes
QUIESCENT
CURRENT
(µA)
300
120
300
120
120
120
300
300
230
NUMBER OF
TRANSMITTERS
ON BUS
32
32
32
128
32
32
32
32
128
PIN
COUNT
8
8
8
8
8
14
8
14
8
1
Low-Power, Slew-Rate-Limited
RS-485/RS-422 Transceivers
ABSOLUTE MAXIMUM RATINGS
Supply Voltage (V
CC
) .............................................................12V
Control Input Voltage (RE,
DE)...................-0.5V to (V
CC
+ 0.5V)
Driver Input Voltage (DI).............................-0.5V to (V
CC
+ 0.5V)
Driver Output Voltage (A, B)...................................-8V to +12.5V
Receiver Input Voltage (A, B).................................-8V to +12.5V
Receiver Output Voltage (RO).....................-0.5V to (V
CC
+0.5V)
Continuous Power Dissipation (T
A
= +70°C)
8-Pin Plastic DIP (derate 9.09mW/°C above +70°C) ....727mW
14-Pin Plastic DIP (derate 10.00mW/°C above +70°C) ..800mW
8-Pin SO (derate 5.88mW/°C above +70°C).................471mW
14-Pin SO (derate 8.33mW/°C above +70°C)...............667mW
8-Pin µMAX (derate 4.1mW/°C above +70°C) ..............830mW
8-Pin CERDIP (derate 8.00mW/°C above +70°C).........640mW
14-Pin CERDIP (derate 9.09mW/°C above +70°C).......727mW
Operating Temperature Ranges
HWD4_ _C_ _/HWD1487C_ A ...............................0°C to +70°C
HWD4_ _E_ _/HWD1487E_ A .............................-40°C to +85°C
HWD4_ _MJ_/HWD1487MJA ...........................-55°C to +125°C
Storage Temperature Range .............................-65°C to +160°C
Lead Temperature (soldering, 10sec) .............................+300°C
DC ELECTRICAL CHARACTERISTICS
(V
CC
= 5V ±5%, T
A
= T
MIN
to T
MAX
, unless otherwise noted.) (Notes 1, 2)
PARAMETER
Differential Driver Output (no load)
Differential Driver Output
(with load)
Change in Magnitude of Driver
Differential Output Voltage for
Complementary Output States
Driver Common-Mode Output
Voltage
Change in Magnitude of Driver
Common-Mode Output Voltage
for Complementary Output States
Input High Voltage
Input Low Voltage
Input Current
SYMBOL
V
OD1
V
OD2
R = 50Ω (RS-422)
R = 27Ω (RS-485), Figure 4
R = 27Ω or 50Ω, Figure 4
R = 27Ω or 50Ω, Figure 4
R = 27Ω or 50Ω, Figure 4
DE, DI,
RE
DE, DI,
RE
DE, DI,
RE
DE = 0V;
V
CC
= 0V or 5.25V,
all devices except
HWD487/HWD1487
HWD
487/HWD1487,
DE = 0V, V
CC
= 0V or 5.25V
Receiver Differential Threshold
Voltage
Receiver Input Hysteresis
Receiver Output High Voltage
Receiver Output Low Voltage
Three-State (high impedance)
Output Current at Receiver
V
TH
∆V
TH
V
OH
V
OL
I
OZR
-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
-7V
≤
V
CM
≤
12V, all devices except
HWD487/HWD1487
Receiver Input Resistance
R
IN
-7V
≤
V
CM
≤
12V, HWD487/HWD1487
48
kΩ
12
3.5
0.4
±1
V
IN
= 12V
V
IN
= -7V
V
IN
= 12V
V
IN
= -7V
-0.2
70
2.0
0.8
±2
1.0
mA
-0.8
0.25
-0.2
0.2
mA
V
mV
V
V
µA
kΩ
2
1.5
5
0.2
3
0.2
CONDITIONS
MIN
TYP
MAX
5
UNITS
V
V
∆V
OD
V
OC
∆V
OD
V
IH
V
IL
I
IN1
V
V
V
V
V
µA
Input Current
(A, B)
I
IN2
2
Low-Power, Slew-Rate-Limited
RS-485/RS-422 Transceivers
DC ELECTRICAL CHARACTERISTICS (continued)
(V
CC
= 5V ±5%, T
A
= T
MIN
to T
MAX
, unless otherwise noted.) (Notes 1, 2)
PARAMETER
SYMBOL
CONDITIONS
HWD488/HWD489,
DE, DI,
RE
= 0V or V
CC
HWD490/HWD491,
DE, DI,
RE
= 0V or V
CC
No-Load Supply Current
(Note 3)
I
CC
HWD481/HWD485,
RE
= 0V or V
CC
HWD1487,
RE
= 0V or V
CC
HWD483/HWD487,
RE
= 0V or V
CC
Supply Current in Shutdown
Driver Short-Circuit Current,
V
O
= High
Driver Short-Circuit Current,
V
O
= Low
Receiver Short-Circuit Current
I
SHDN
I
OSD1
I
OSD2
I
OSR
DE = V
CC
DE = 0V
DE = V
CC
DE = 0V
DE = 5V
HWD483
HWD487
MIN
TYP
120
300
500
300
300
230
350
250
120
0.1
35
35
7
MAX
250
500
900
500
500
400
650
400
250
10
250
250
95
µA
UNITS
DE = 0V
HWD481/483/487, DE = 0V,
RE
= V
CC
-7V
≤
V
O
≤12V
(Note 4)
-7V
≤
V
O
≤12V
(Note 4)
0V
≤
V
O
≤
V
CC
µA
mA
mA
mA
SWITCHING CHARACTERISTICS—HWD481/HWD485,
HWD490/HWD491, HWD1487
(V
CC
= 5V ±5%, T
A
= T
MIN
to T
MAX
, unless otherwise noted.) (Notes 1, 2)
PARAMETER
Driver Input to Output
Driver Output Skew to Output
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
Receiver Input to Output
SYMBOL
CONDITIONS
t
PLH
Figures 6 and 8, R
DIFF
= 54Ω,
C
L1
= C
L2
= 100pF
t
PHL
t
SKEW
Figures 6 and 8, R
DIFF
= 54Ω, C
L1
= C
L2
= 100pF
HWD481, HWD485, HWD1487
Figures 6 and 8,
R
DIFF
= 54Ω,
t
R
, t
F
HWD490C/E, HWD491C/E
C
L1
= C
L2
= 100pF HWD490M, HWD491M
t
ZH
Figures 7 and 9, C
L
= 100pF, S2 closed
t
ZL
Figures 7 and 9, C
L
= 100pF, S1 closed
t
LZ
Figures 7 and 9, C
L
= 15pF, S1 closed
t
HZ
Figures 7 and 9, C
L
= 15pF, S2 closed
Figures 6 and 10, HWD481, HWD485, HWD1487
t
PLH
, t
PHL
R
DIFF
= 54Ω,
HWD490C/E, HWD491C/E
C
L1
= C
L2
= 100pF HWD490M, HWD491M
t
SKD
t
ZL
t
ZH
t
LZ
t
HZ
f
MAX
t
SHDN
HWD481 (Note 5)
Figures 6 and 10, R
DIFF
= 54Ω,
C
L1
= C
L2
= 100pF
Figures 5 and 11, C
RL
= 15pF, S1 closed
Figures 5 and 11, C
RL
= 15pF, S2 closed
Figures 5 and 11, C
RL
= 15pF, S1 closed
Figures 5 and 11, C
RL
= 15pF, S2 closed
2.5
50
MIN
10
10
3
5
3
TYP
30
30
5
15
15
15
40
40
40
40
90
90
90
13
20
20
20
20
200
50
50
50
50
600
MAX
60
60
10
40
25
40
70
70
70
70
200
150
200
UNITS
ns
ns
ns
ns
ns
ns
ns
ns
20
20
20
|
t
PLH
- t
PHL
|
Differential
Receiver Skew
Receiver Enable to Output Low
Receiver Enable to Output High
Receiver Disable Time from Low
Receiver Disable Time from High
Maximum Data Rate
Time to Shutdown
ns
ns
ns
ns
ns
Mbps
ns
3
Low-Power, Slew-Rate-Limited
RS-485/RS-422 Transceivers
SWITCHING CHARACTERISTICS—HWD481/HWD485,
HWD490/HWD491, HWD1487
(continued)
(V
CC
= 5V ±5%, T
A
= T
MIN
to T
MAX
, unless otherwise noted.) (Notes 1, 2)
PARAMETER
SYMBOL
CONDITIONS
Figures 7 and 9, C
L
= 100pF, S2 closed
Figures 7 and 9, C
L
= 100pF, S1 closed
Figures 5 and 11, C
L
= 15pF, S2 closed,
A - B = 2V
Figures 5 and 11, C
L
= 15pF, S1 closed,
B - A = 2V
MIN
TYP
40
40
300
300
MAX
100
100
1000
1000
UNITS
ns
ns
ns
ns
Driver Enable from Shutdown to
t
ZH(SHDN)
Output High (HWD481)
Driver Enable from Shutdown to
t
ZL(SHDN)
Output Low (HWD481)
Receiver Enable from Shutdown
t
ZH(SHDN)
to Output High (HWD481)
Receiver Enable from Shutdown
t
ZL(SHDN)
to Output Low (HWD481)
SWITCHING CHARACTERISTICS—HWD483,
HWD487/HWD488/HWD489
(V
CC
= 5V ±5%, T
A
= T
MIN
to T
MAX
, unless otherwise noted.) (Notes 1, 2)
PARAMETER
Driver Input to Output
Driver Output Skew to Output
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
Receiver Input to Output
SYMBOL
t
PLH
t
PHL
t
SKEW
t
R
, t
F
t
ZH
t
ZL
t
LZ
t
HZ
t
PLH
t
PHL
t
SKD
t
ZL
t
ZH
t
LZ
t
HZ
f
MAX
t
SHDN
t
ZH(SHDN)
t
ZL(SHDN)
t
ZH(SHDN)
t
ZL(SHDN)
CONDITIONS
Figures 6 and 8, R
DIFF
= 54Ω,
C
L1
= C
L2
= 100pF
Figures 6 and 8, R
DIFF
= 54Ω,
C
L1
= C
L2
= 100pF
Figures 6 and 8, R
DIFF
= 54Ω,
C
L1
= C
L2
= 100pF
Figures 7 and 9, C
L
= 100pF, S2 closed
Figures 7 and 9, C
L
= 100pF, S1 closed
Figures 7 and 9, C
L
= 15pF, S1 closed
Figures 7 and 9, C
L
= 15pF, S2 closed
Figures 6 and 10, R
DIFF
= 54Ω,
C
L1
= C
L2
= 100pF
Figures 6 and 10, R
DIFF
= 54Ω,
C
L1
= C
L2
= 100pF
Figures 5 and 11, C
RL
= 15pF, S1 closed
Figures 5 and 11, C
RL
= 15pF, S2 closed
Figures 5 and 11, C
RL
= 15pF, S1 closed
Figures 5 and 11, C
RL
= 15pF, S2 closed
t
PLH
, t
PHL
< 50% of data period
HWD483/HWD487 (Note 5)
HWD483/HWD487, Figures 7 and 9,
C
L
= 100pF, S2 closed
HWD483/HWD487, Figures 7 and 9,
C
L
= 100pF, S1 closed
HWD483/HWD487, Figures 5 and 11,
C
L
= 15pF, S2 closed
HWD483/HWD487, Figures 5 and 11,
C
L
= 15pF, S1 closed
250
50
200
600
2000
2000
2500
2500
250
250
250
300
300
250
250
100
20
20
20
20
50
50
50
50
MIN
250
250
TYP
800
800
100
MAX
2000
2000
800
2000
2000
2000
3000
3000
2000
2000
UNITS
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
kbps
ns
ns
ns
ns
ns
I
t
PLH
- t
PHL
I
Differential
Receiver Skew
Receiver Enable to Output Low
Receiver Enable to Output High
Receiver Disable Time from Low
Receiver Disable Time from High
Maximum Data Rate
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
4
Low-Power, Slew-Rate-Limited
RS-485/RS-422 Transceivers
NOTES FOR ELECTRICAL/SWITCHING CHARACTERISTICS
Note 1:
All currents into device pins are positive; all currents out of device pins are negative. All voltages are referenced to device
ground unless otherwise specified.
Note 2:
All typical specifications are given for V
CC
= 5V and T
A
= +25°C.
Note 3:
Supply current specification is valid for loaded transmitters when DE = 0V.
Note 4:
Applies to peak current. See
Typical Operating Characteristics.
Note 5:
The HWD481/HWD483/HWD487 are put into shutdown by bringing
RE
high and DE low. If the inputs are in this state for less
than 50ns, the parts are guaranteed not to enter shutdown. If the inputs are in this state for at least 600ns, the parts are
guaranteed to have entered shutdown. See
Low-Power Shutdown Mode
section.
__________________________________________Typical Operating Characteristics
(V
CC
= 5V, T
A
= +25°C, unless otherwise noted.)
OUTPUT CURRENT vs.
RECEIVER OUTPUT LOW VOLTAGE
45
40
OUTPUT CURRENT (mA)
OUTPUT CURRENT (mA)
35
30
25
20
15
10
5
0
0
0.5
1.0
1.5
2.0
2.5
OUTPUT LOW VOLTAGE (V)
-20
-18
-16
-14
-12
-10
-8
-6
-4
-2
0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
OUTPUT HIGH VOLTAGE (V)
OUTPUT HIGH VOLTAGE (V)
OUTPUT CURRENT vs.
RECEIVER OUTPUT HIGH VOLTAGE
4.8
4.6
4.4
4.2
4.0
3.8
3.6
3.4
3.2
3.0
RECEIVER OUTPUT HIGH VOLTAGE vs.
TEMPERATURE
I
RO
= 8mA
-50
-25
0
25
50
75
100
125
TEMPERATURE (°C)
RECEIVER OUTPUT LOW VOLTAGE vs.
TEMPERATURE
0.9
0.8
OUTPUT LOW VOLTAGE (V)
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
-50
-25
0
25
50
75
100
125
TEMPERATURE (°C)
I
RO
= 8mA
OUTPUT CURRENT (mA)
90
80
70
60
50
40
30
20
10
0
0
DRIVER OUTPUT CURRENT vs.
DIFFERENTIAL OUTPUT VOLTAGE
2.4
DIFFERENTIAL OUTPUT VOLTAGE (V)
2.3
2.2
2.1
2.0
1.9
1.8
1.7
1.6
1.5
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5
DIFFERENTIAL OUTPUT VOLTAGE (V)
DRIVER DIFFERENTIAL OUTPUT VOLTAGE
vs. TEMPERATURE
R = 54Ω
-50
-25
0
25
50
75
100
125
TEMPERATURE (°C)
5
