ETC1 HWD490MJA Low-power, slew-rate-limited rs-485/rs-422 transceiver Datasheet

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 RS422 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-impedance 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 communications are obtained using the HWD488–HWD491, while
the HWD481, HWD483, HWD485, HWD487, and HWD1487
are designed for half-duplex applications.
________________________Applications
Low-Power RS-485 Transceivers
Low-Power RS-422 Transceivers
Level Translators
__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
Transceivers for EMI-Sensitive Applications
Industrial-Control Local Area Networks
Ordering Information appears at end of data sheet.
______________________________________________________________Selection Table
PART
NUMBER
HALF/FULL
DUPLEX
DATA RATE
(Mbps)
SLEW-RATE
LIMITED
LOW-POWER
SHUTDOWN
RECEIVER/
DRIVER
ENABLE
QUIESCENT
CURRENT
(µA)
NUMBER OF
TRANSMITTERS
ON BUS
PIN
COUNT
HWD481
Half
2.5
No
Yes
Yes
300
32
8
HWD483
Half
0.25
Yes
Yes
Yes
120
32
8
HWD485
Half
2.5
No
No
Yes
300
32
8
HWD487
Half
0.25
Yes
Yes
Yes
120
128
8
HWD488
Full
0.25
Yes
No
No
120
32
8
HWD489
Full
0.25
Yes
No
Yes
120
32
14
HWD490
Full
2.5
No
No
No
300
32
8
HWD491
Full
2.5
No
No
Yes
300
32
14
HWD1487
Half
2.5
No
No
Yes
230
128
8
1
Low-Power, Slew-Rate-Limited
RS-485/RS-422 Transceivers
ABSOLUTE MAXIMUM RATINGS
Supply Voltage (VCC) .............................................................12V
Control Input Voltage (RE, DE)...................-0.5V to (VCC + 0.5V)
Driver Input Voltage (DI).............................-0.5V to (VCC + 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 (VCC +0.5V)
Continuous Power Dissipation (TA = +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
(VCC = 5V ±5%, TA = TMIN to TMAX, unless otherwise noted.) (Notes 1, 2)
PARAMETER
SYMBOL
Differential Driver Output (no load)
VOD1
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
VOD2
CONDITIONS
MIN
R = 50Ω (RS-422)
TYP
MAX
UNITS
5
V
2
R = 27Ω (RS-485), Figure 4
1.5
5
V
∆VOD
R = 27Ω or 50Ω, Figure 4
0.2
V
VOC
R = 27Ω or 50Ω, Figure 4
3
V
∆VOD
R = 27Ω or 50Ω, Figure 4
0.2
V
Input High Voltage
VIH
DE, DI, RE
Input Low Voltage
VIL
DE, DI, RE
0.8
V
Input Current
IIN1
DE, DI, RE
±2
µA
IIN2
DE = 0V;
VCC = 0V or 5.25V,
all devices except
HWD487/HWD1487
Input Current
(A, B)
2.0
HWD487/HWD1487,
DE = 0V, VCC = 0V or 5.25V
Receiver Differential Threshold
Voltage
VTH
V
VIN = 12V
1.0
VIN = -7V
-0.8
VIN = 12V
0.25
VIN = -7V
-0.2
mA
-7V ≤ VCM ≤ 12V
-0.2
0.2
V
Receiver Input Hysteresis
∆VTH
VCM = 0V
Receiver Output High Voltage
VOH
IO = -4mA, VID = 200mV
Receiver Output Low Voltage
VOL
IO = 4mA, VID = -200mV
0.4
V
Three-State (high impedance)
Output Current at Receiver
IOZR
0.4V ≤ VO ≤ 2.4V
±1
µA
Receiver Input Resistance
70
mA
mV
3.5
V
-7V ≤ VCM ≤ 12V, all devices except
HWD487/HWD1487
12
kΩ
-7V ≤ VCM ≤ 12V, HWD487/HWD1487
48
kΩ
RIN
2
Low-Power, Slew-Rate-Limited
RS-485/RS-422 Transceivers
DC ELECTRICAL CHARACTERISTICS (continued)
(VCC = 5V ±5%, TA = TMIN to TMAX, unless otherwise noted.) (Notes 1, 2)
PARAMETER
No-Load Supply Current
(Note 3)
SYMBOL
ICC
CONDITIONS
MIN
TYP
MAX
HWD488/HWD489,
DE, DI, RE = 0V or VCC
120
250
HWD490/HWD491,
DE, DI, RE = 0V or VCC
300
500
UNITS
HWD481/HWD485,
RE = 0V or VCC
DE = VCC
500
900
DE = 0V
300
500
HWD1487,
RE = 0V or VCC
DE = VCC
300
500
DE = 0V
230
400
HWD483
350
650
HWD487
250
120
0.1
400
250
10
µA
HWD483/HWD487,
RE = 0V or VCC
DE = 5V
µA
Supply Current in Shutdown
ISHDN
DE = 0V
HWD481/483/487, DE = 0V, RE = VCC
Driver Short-Circuit Current,
VO = High
IOSD1
-7V ≤ VO ≤12V (Note 4)
35
250
mA
Driver Short-Circuit Current,
VO = Low
IOSD2
-7V ≤ VO ≤12V (Note 4)
35
250
mA
Receiver Short-Circuit Current
IOSR
0V ≤ VO ≤ VCC
7
95
mA
SWITCHING CHARACTERISTICS—HWD481/HWD485, HWD490/HWD491, HWD1487
(VCC = 5V ±5%, TA = TMIN to TMAX, 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
| tPLH - tPHL | 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
SYMBOL
CONDITIONS
tPLH
Figures 6 and 8, RDIFF = 54Ω,
CL1 = CL2 = 100pF
tPHL
tSKEW
Figures 6 and 8, RDIFF = 54Ω, CL1 = CL2 = 100pF
HWD481, HWD485, HWD1487
Figures 6 and 8,
RDIFF = 54Ω,
tR, tF
HWD490C/E, HWD491C/E
CL1 = CL2 = 100pF HWD490M, HWD491M
tZH
Figures 7 and 9, CL = 100pF, S2 closed
tZL
Figures 7 and 9, CL = 100pF, S1 closed
tLZ
Figures 7 and 9, CL = 15pF, S1 closed
tHZ
Figures 7 and 9, CL = 15pF, S2 closed
Figures 6 and 10, HWD481, HWD485, HWD1487
tPLH, tPHL RDIFF = 54Ω,
HWD490C/E, HWD491C/E
CL1 = CL2 = 100pF HWD490M, HWD491M
MIN
10
10
3
5
3
20
20
20
TYP
30
30
5
15
15
15
40
40
40
40
90
90
90
MAX
60
60
10
40
25
40
70
70
70
70
200
150
200
tSKD
Figures 6 and 10, RDIFF = 54Ω,
CL1 = CL2 = 100pF
13
tZL
tZH
tLZ
tHZ
Figures 5 and 11, CRL = 15pF, S1 closed
Figures 5 and 11, CRL = 15pF, S2 closed
Figures 5 and 11, CRL = 15pF, S1 closed
Figures 5 and 11, CRL = 15pF, S2 closed
20
20
20
20
50
50
50
50
200
600
fMAX
tSHDN
HWD481 (Note 5)
3
2.5
50
UNITS
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
Mbps
ns
Low-Power, Slew-Rate-Limited
RS-485/RS-422 Transceivers
SWITCHING CHARACTERISTICS—HWD481/HWD485, HWD490/HWD491, HWD1487 (continued)
(VCC = 5V ±5%, TA = TMIN to TMAX, unless otherwise noted.) (Notes 1, 2)
PARAMETER
SYMBOL
TYP
MAX
UNITS
Figures 7 and 9, CL = 100pF, S2 closed
40
100
ns
Driver Enable from Shutdown to
tZL(SHDN)
Output Low (HWD481)
Figures 7 and 9, CL = 100pF, S1 closed
40
100
ns
Receiver Enable from Shutdown
tZH(SHDN)
to Output High (HWD481)
Figures 5 and 11, CL = 15pF, S2 closed,
A - B = 2V
300
1000
ns
Receiver Enable from Shutdown
tZL(SHDN)
to Output Low (HWD481)
Figures 5 and 11, CL = 15pF, S1 closed,
B - A = 2V
300
1000
ns
UNITS
Driver Enable from Shutdown to
tZH(SHDN)
Output High (HWD481)
CONDITIONS
MIN
SWITCHING CHARACTERISTICS—HWD483, HWD487/HWD488/HWD489
(VCC = 5V ±5%, TA = TMIN to TMAX, unless otherwise noted.) (Notes 1, 2)
PARAMETER
Driver Input to Output
SYMBOL
tPLH
tPHL
CONDITIONS
Figures 6 and 8, RDIFF = 54Ω,
CL1 = CL2 = 100pF
MIN
250
TYP
800
MAX
2000
250
800
2000
100
800
ns
ns
Driver Output Skew to Output
tSKEW
Figures 6 and 8, RDIFF = 54Ω,
CL1 = CL2 = 100pF
Driver Rise or Fall Time
tR, tF
Figures 6 and 8, RDIFF = 54Ω,
CL1 = CL2 = 100pF
250
2000
ns
Driver Enable to Output High
tZH
Figures 7 and 9, CL = 100pF, S2 closed
250
2000
ns
Driver Enable to Output Low
tZL
Figures 7 and 9, CL = 100pF, S1 closed
250
2000
ns
Driver Disable Time from Low
tLZ
Figures 7 and 9, CL = 15pF, S1 closed
300
3000
ns
Driver Disable Time from High
tHZ
Figures 7 and 9, CL = 15pF, S2 closed
300
3000
ns
tPLH
Figures 6 and 10, RDIFF = 54Ω,
CL1 = CL2 = 100pF
250
2000
250
2000
Receiver Input to Output
I tPLH - tPHL I Differential
Receiver Skew
tPHL
tSKD
Figures 6 and 10, RDIFF = 54Ω,
CL1 = CL2 = 100pF
100
ns
ns
Receiver Enable to Output Low
tZL
Figures 5 and 11, CRL = 15pF, S1 closed
20
50
ns
Receiver Enable to Output High
tZH
Figures 5 and 11, CRL = 15pF, S2 closed
20
50
ns
Receiver Disable Time from Low
tLZ
Figures 5 and 11, CRL = 15pF, S1 closed
20
50
ns
Receiver Disable Time from High
tHZ
Figures 5 and 11, CRL = 15pF, S2 closed
20
50
Maximum Data Rate
fMAX
tPLH, tPHL < 50% of data period
250
Time to Shutdown
tSHDN
HWD483/HWD487 (Note 5)
50
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
tZH(SHDN)
tZL(SHDN)
tZH(SHDN)
tZL(SHDN)
HWD483/HWD487, Figures 7 and 9,
CL = 100pF, S2 closed
HWD483/HWD487, Figures 7 and 9,
CL = 100pF, S1 closed
HWD483/HWD487, Figures 5 and 11,
CL = 15pF, S2 closed
HWD483/HWD487, Figures 5 and 11,
CL = 15pF, S1 closed
4
ns
kbps
200
600
ns
2000
ns
2000
ns
2500
ns
2500
ns
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 VCC = 5V and TA = +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
(VCC = 5V, TA = +25°C, unless otherwise noted.)
OUTPUT CURRENT vs.
RECEIVER OUTPUT HIGH VOLTAGE
-20
40
-18
35
-16
30
25
20
15
10
4.8
-14
-12
-10
-8
-6
0.5
1.0
1.5
2.0
1.5
2.5
4.2
4.0
3.8
3.6
3.4
3.0
0
0
4.4
3.2
-2
0
IRO = 8mA
4.6
-4
5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
-50
-25
0
25
50
75
100
125
OUTPUT LOW VOLTAGE (V)
OUTPUT HIGH VOLTAGE (V)
TEMPERATURE (°C)
RECEIVER OUTPUT LOW VOLTAGE vs.
TEMPERATURE
DRIVER OUTPUT CURRENT vs.
DIFFERENTIAL OUTPUT VOLTAGE
DRIVER DIFFERENTIAL OUTPUT VOLTAGE
vs. TEMPERATURE
0.9
2.4
IRO = 8mA
DIFFERENTIAL OUTPUT VOLTAGE (V)
90
0.8
80
0.7
OUTPUT CURRENT (mA)
OUTPUT LOW VOLTAGE (V)
RECEIVER OUTPUT HIGH VOLTAGE vs.
TEMPERATURE
OUTPUT HIGH VOLTAGE (V)
45
OUTPUT CURRENT (mA)
OUTPUT CURRENT (mA)
OUTPUT CURRENT vs.
RECEIVER OUTPUT LOW VOLTAGE
0.6
0.5
0.4
0.3
0.2
0.1
70
60
50
40
30
20
10
0
-25
0
25
50
75
TEMPERATURE (°C)
100
125
2.2
2.1
2.0
1.9
1.8
1.7
1.6
1.5
0
-50
R = 54Ω
2.3
0
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5
DIFFERENTIAL OUTPUT VOLTAGE (V)
5
-50
-25
0
25
50
75
TEMPERATURE (°C)
100
125
Low-Power, Slew-Rate-Limited
RS-485/RS-422 Transceivers
____________________________Typical Operating Characteristics (continued)
(VCC = 5V, TA = +25°C, unless otherwise noted.)
HWD481/HWD485/HWD490/HWD491
SUPPLY CURRENT vs. TEMPERATURE
OUTPUT CURRENT vs.
DRIVER OUTPUT HIGH VOLTAGE
OUTPUT CURRENT vs.
DRIVER OUTPUT LOW VOLTAGE
140
-120
600
120
-100
500
80
60
40
20
SUPPLY CURRENT (µA)
OUTPUT CURRENT (mA)
100
-80
-60
-40
400
300
HWD485; DE = 0, RE = X,
HWD481; DE = RE = 0
HWD490/HWD491; DE = RE = X
200
-20
100
0
0
HWD481; DE = 0, RE = VCC
0
2
4
8
6
-7 -6 -5 -4 -3 -2 -1 0 1
12
10
600
600
500
500
HWD483; DE = VCC, RE = X
300
HWD487; DE = VCC, RE = X
200
-50
4 5
-25
0
25
HWD483/HWD487; DE = RE = 0,
HWD488/HWD489; DE = RE = X
400
300
HWD1487; DE = VCC, RE = X
200
HWD1487; DE = 0V, RE = X
100
100
HWD483/HWD487; DE = 0, RE = VCC
0
0
-50
-25
0
25
50
75
100
125
-60 -40 -20
0 20 40
60 80 100 120 140
TEMPERATURE (°C)
TEMPERATURE (°C)
6
50
75
TEMPERATURE (°C)
HWD1487
SUPPLY CURRENT vs. TEMPERATURE
HWD483/HWD487–HWD489
SUPPLY CURRENT vs. TEMPERATURE
400
3
2
OUTPUT HIGH VOLTAGE (V)
OUTPUT LOW VOLTAGE (V)
SUPPLY CURRENT (µA)
0
SUPPLY CURRENT (µA)
OUTPUT CURRENT (mA)
HWD481/HWD485; DE = VCC, RE = X
100
125
Low-Power, Slew-Rate-Limited
RS-485/RS-422 Transceivers
______________________________________________________________Pin Description
PIN
HWD481/HWD483/
HWD485/HWD487/
HWD1487
HWD488/
HWD490
HWD489/
HWD491
NAME
NAME
FUNCTION
FUNCTION
DIP/SO
µMAX
DIP/SO
µMAX
DIP/SO
1
3
2
4
2
RO
Receiver Output: If A > B by 200mV, RO will be high;
If A < B by 200mV, RO will be low.
2
4
—
—
3
RE
Receiver Output Enable. RO is enabled when RE is low; RO is
high impedance when RE is high.
3
5
—
—
4
DE
Driver Output Enable. The driver outputs, Y and Z, are enabled
by bringing DE high. They are high impedance when DE is low. If
the driver outputs are enabled, the parts function as line drivers.
While they are high impedance, they function as line receivers if
RE is low.
4
6
3
5
5
DI
Driver Input. A low on DI forces output Y low and output Z high.
Similarly, a high on DI forces output Y high and output Z low.
5
7
4
6
6, 7
GND
—
—
5
7
9
Y
Noninverting Driver Output
—
—
6
8
10
Z
Inverting Driver Output
6
8
—
—
—
A
Noninverting Receiver Input and Noninverting Driver Output
—
—
8
2
12
A
Noninverting Receiver Input
7
1
—
—
—
B
Inverting Receiver Input and Inverting Driver Output
—
—
7
1
11
B
Inverting Receiver Input
8
2
1
3
14
VCC
Positive Supply: 4.75V ≤ VCC ≤ 5.25V
—
—
—
—
1, 8, 13
N.C.
No Connect—not internally connected
Ground
TOP VIEW
RO
1
R
8
VCC
RE 2
7
B
DE 3
6
A
5
GND
DI 4
D
1
VCC
2
RO
3
RE 4
µMAX
R
8 VCC
7B
Rt
6
A
5 GND
DE 3
8
HWD481
HWD483
HWD485
HWD487
HWD1487
1
RE 2
DIP/SO
B
RO
A
7
GND
6
DI
5
DE
DI 4
D
HWD481
HWD483
HWD485
HWD487
HWD1487
DE
D
DI
B
Rt
A
RO
R
RE
NOTE: PIN LABELS Y AND Z ON TIMING, TEST, AND WAVEFORM DIAGRAMS REFER TO PINS A AND B WHEN DE IS HIGH.
TYPICAL OPERATING CIRCUIT SHOWN WITH DIP/SO PACKAGE.
Figure 1. HWD481/HWD483/HWD485/HWD487/HWD1487 Pin Configuration and Typical Operating Circuit
7
Low-Power, Slew-Rate-Limited
RS-485/RS-422 Transceivers
TOP VIEW
VCC
VCC
8
A
RO 2
7
B
DI 3
6
Z
GND 4
5
Y
DI
Z
RO
VCC 1
R
D
HWD488
HWD490
1
5 Y
3
Rt
D
6 Z
R
RO
DIP/SO
8 A
B
1
A
2
VCC
3
RO
4
8
HWD488
HWD490
7
Y
6
GND
5
DI
2
Rt
R
D
7
DI
B
4
GND
µMAX
GND
NOTE: TYPICAL OPERATING CIRCUIT SHOWN WITH DIP/SO PACKAGE.
Figure 2. HWD488/HWD490 Pin Configuration and Typical Operating Circuit
TOP VIEW
DE
VCC
4
N.C.
1
14 V CC
R
RO
2
RE
3
12 A
DE
4
11 B
DI
5
10 Z
GND
6
GND
7
13 N.C.
D
9
Y
8
N.C.
VCC RE
HWD489
HWD491
14
9
DI
5
Y
Rt
D
10
RO
R
Z
12
RO
2
R
A
Rt
D
11
DI
B
NC
1, 8, 13
3
DIP/SO
6, 7
RE GND
GND
DE
Figure 3. HWD489/HWD491 Pin Configuration and Typical Operating Circuit
__________Applications Information
The HWD481/HWD483/HWD485/HWD487–HWD491 and
HWD1487 are low-power transceivers for RS-485 and RS422 communications. The HWD481, HWD485, HWD490,
HWD491, and HWD1487 can transmit and receive at data
rates up to 2.5Mbps, while the HWD483, HWD487,
HWD488, and HWD489 are specified for data rates up to
250kbps. The HWD488–HWD491 are full-duplex transceivers while the HWD481, HWD483, HWD485, HWD487,
and HWD1487 are half-duplex. In addition, Driver Enable
(DE) and Receiver Enable (RE) pins are included on the
HWD481, HWD483, HWD485, HWD487, HWD489,
HWD491, and HWD1487. When disabled, the driver and
receiver outputs are high impedance.
8
HWD487/HWD1487:
128 Transceivers on the Bus
The 48kΩ, 1/4-unit-load receiver input impedance of the
HWD487 and HWD1487 allows up to 128 transceivers
on a bus, compared to the 1-unit load (12kΩ input
impedance) of standard RS-485 drivers (32 transceivers maximum). Any combination of HWD487/
HWD1487 and other RS-485 transceivers with a total of
32 unit loads or less can be put on the bus. The
HWD481/HWD483/HWD485 and HWD488–HWD491 have
standard 12kΩ Receiver Input impedance.
Low-Power, Slew-Rate-Limited
RS-485/RS-422 Transceivers
_________________________________________________________________Test Circuits
Y
R
TEST POINT
RECEIVER
OUTPUT
CRL
15pF
VOD
R
1kΩ
VCC
S1
1kΩ
VOC
S2
Z
Figure 4. Driver DC Test Load
3V
DE
DI
Figure 5. Receiver Timing Test Load
CL1
Y
500Ω
A
RDIFF
VID
VCC
OUTPUT
UNDER TEST
RO
CL
B
Z
S1
S2
RE
CL2
Figure 6. Driver/Receiver Timing Test Circuit
Figure 7. Driver Timing Test Load
HWD483/HWD487/HWD488/HWD489:
Reduced EMI and Reflections
The HWD483 and HWD487–HWD489 are slew-rate limited, minimizing EMI and reducing reflections caused by
improperly terminated cables. Figure 12 shows the driver output waveform and its Fourier analysis of a
150kHz signal transmitted by a HWD481, HWD485,
HWD490, HWD491, or HWD1487. High-frequency har-
9
monics with large amplitudes are evident. Figure 13
shows the same information displayed for a HWD483,
HWD487, HWD488, or HWD489 transmitting under the
same conditions. Figure 13’s high-frequency harmonics
have much lower amplitudes, and the potential for EMI
is significantly reduced.
Low-Power, Slew-Rate-Limited
RS-485/RS-422 Transceivers
_______________________________________________________Switching Waveforms
3V
3V
DI
1.5V
DE
1.5V
0V
tPHL
tPLH
1.5V
1/2 VO
tLZ
tZL(SHDN), tZL
Z
Y, Z
VO
2.3V OUTPUT NORMALLY LOW
VOL
Y
1/2 VO
VO
VDIFF
0V
-VO
1.5V
0V
VDIFF = V (Y) - V (Z)
VOH -0.5V
2.3V
90%
tR
OUTPUT NORMALLY HIGH
Y, Z
90%
10%
VOL +0.5V
0V
10%
tZH(SHDN), tZH
tF
tHZ
tSKEW = | tPLH - tPHL |
Figure 8. Driver Propagation Delays
Figure 9. Driver Enable and Disable Times (except HWD488 and
HWD490)
3V
RE
1.5V
1.5V
0V
RO
A-B
VOH
1.5V
VOL
tPHL
VID
-VID
0V
VCC
RO
tPLH
1.5V OUTPUT NORMALLY LOW
0V
INPUT
tLZ
tZL(SHDN), tZL
1.5V
OUTPUT
VOL + 0.5V
OUTPUT NORMALLY HIGH
RO
VOH - 0.5V
1.5V
0V
tZH(SHDN), tZH
tHZ
Figure 11. Receiver Enable and Disable Times (except HWD488
and HWD490)
Figure 10. Receiver Propagation Delays
_________________Function Tables (HWD481/HWD483/HWD485/HWD487/HWD1487)
Table 1. Transmitting
Table 2. Receiving
INPUTS
OUTPUTS
INPUTS
OUTPUT
RE
DE
DI
Z
Y
RE
DE
A-B
RO
X
1
1
0
1
0
0
> +0.2V
1
X
1
0
1
0
0
0
< -0.2V
0
0
0
X
High-Z
High-Z
0
0
Inputs open
1
1
0
X
High-Z*
High-Z*
1
0
X
High-Z*
X = Don't care
High-Z = High impedance
* Shutdown mode for HWD481/HWD483/HWD487
X = Don't care
High-Z = High impedance
* Shutdown mode for HWD481/HWD483/HWD487
10
Low-Power, Slew-Rate-Limited
RS-485/RS-422 Transceivers
10dB/div
10dB/div
0Hz
0Hz
5MHz
5MHz
500kHz/div
500kHz/div
Figure 12. Driver Output Waveform and FFT Plot of HWD481/
HWD485/HWD490/HWD491/HWD1487 Transmitting a 150kHz
Signal
Figure 13. Driver Output Waveform and FFT Plot of HWD483/
HWD487–HWD489 Transmitting a 150kHz Signal
Low-Power Shutdown Mode
(HWD481/HWD483/HWD487)
A low-power shutdown mode is initiated by bringing
both RE high and DE low. The devices will not shut
down unless both the driver and receiver are disabled.
In shutdown, the devices typically draw only 0.1µA of
supply current.
RE and DE may be driven simultaneously; the parts are
guaranteed not to enter shutdown if RE is high and DE
is low for less than 50ns. If the inputs are in this state
for at least 600ns, the parts are guaranteed to enter
shutdown.
For the HWD481, HWD483, and HWD487, the tZH and
tZL enable times assume the part was not in the lowpower shutdown state (the HWD485/HWD488–HWD491
and HWD1487 can not be shut down). The tZH(SHDN)
and tZL(SHDN) enable times assume the parts were shut
down (see Electrical Characteristics).
It takes the drivers and receivers longer to become
enabled from the low-power shutdown state
(tZH(SHDN), tZL(SHDN)) than from the operating mode
–—–
(tZH, tZL). (The parts are in operating mode if the RE ,
DE inputs equal a logical 0,1 or 1,1 or 0, 0.)
11
Driver Output Protection
Excessive output current and power dissipation caused
by faults or by bus contention are prevented by two
mechanisms. A foldback current limit on the output
stage provides immediate protection against short circuits over the whole common-mode voltage range (see
Typical Operating Characteristics). In addition, a thermal shutdown circuit forces the driver outputs into a
high-impedance state if the die temperature rises
excessively.
Propagation Delay
Many digital encoding schemes depend on the difference between the driver and receiver propagation
delay times. Typical propagation delays are shown in
Figures 15–18 using Figure 14’s test circuit.
The difference in receiver delay times, | tPLH - tPHL |, is
typically under 13ns for the HWD481, HWD485,
HWD490, HWD491, and HWD1487 and is typically less
than 100ns for the HWD483 and HWD487–HWD489.
The driver skew times are typically 5ns (10ns max) for
the HWD481, HWD485, HWD490, HWD491, and
HWD1487, and are typically 100ns (800ns max) for the
HWD483 and HWD487–HWD489.
Low-Power, Slew-Rate-Limited
RS-485/RS-422 Transceivers
100pF
Z
TTL IN
tR, tF < 6ns
B
R
D
Y
R = 54Ω
RECEIVER
OUT
A
100pF
Figure 14. Receiver Propagation Delay Test Circuit
A
B
VCC = 5V
TA = +25°C
500mV/div
VCC = 5V
TA = +25°C
500mV/div
B
A
RO
2V/div
2V/div
RO
20ns/div
20ns/div
Figure 15. HWD481/HWD485/HWD490/HWD491/HWD487
Receiver tPHL
Figure 16. HWD481/HWD485/HWD490/HWD491/HWD1487
Receiver tPLH
A
B
500mV/div
500mV/div
VCC = 5V
TA = +25°C
B
VCC = 5V
TA = +25°C
A
RO
2V/div
2V/div
RO
400ns/div
400ns/div
Figure 17. HWD483, HWD487–HWD489 Receiver tPHL
Figure 18. HWD483, HWD487–HWD489 Receiver tPLH
12
Low-Power, Slew-Rate-Limited
RS-485/RS-422 Transceivers
Line Length vs. Data Rate
Figures 21 and 22 show typical network applications
circuits. These parts can also be used as line
repeaters, with cable lengths longer than 4000 feet, as
shown in Figure 23.
The RS-485/RS-422 standard covers line lengths up to
4000 feet. For line lengths greater than 4000 feet, see
Figure 23.
Figures 19 and 20 show the system differential voltage
for the parts driving 4000 feet of 26AWG twisted-pair
wire at 110kHz into 120Ω loads.
Typical Applications
The HWD481, HWD483, HWD485, HWD487–HWD491, and
HWD1487 transceivers are designed for bidirectional data
communications on multipoint bus transmission lines.
To minimize reflections, the line should be terminated at
both ends in its characteristic impedance, and stub
lengths off the main line should be kept as short as possible. The slew-rate-limited HWD483 and HWD487–HWD489
are more tolerant of imperfect termination.
5V
DI
5V
DI
0V
0V
1V
VY-VZ
1V
VY-VZ
0V
0V
-1V
-1V
5V
RO
5V
RO
0V
0V
2µs/div
2µs/div
Figure 19. HWD481/HWD485/HWD490/HWD491/HWD1487 System
Differential Voltage at 110kHz Driving 4000ft of Cable
Figure 20. HWD483, HWD487–HWD489 System Differential
Voltage at 110kHz Driving 4000ft of Cable
120Ω
120Ω
DI
DE
B
B
D
D
DI
DE
RO
RE
A
B
A
B
A
A
R
R
RO
RE
R
HWD481
HWD483
HWD485
HWD487
HWD1487
R
D
D
DI
DE
DI
RO RE
DE
RO RE
Figure 21. HWD481/HWD483/HWD485/HWD487/HWD1487 Typical Half-Duplex RS-485 Network
13
Low-Power, Slew-Rate-Limited
RS-485/RS-422 Transceivers
A
Y
120Ω
120Ω
R
RO
RE
D
B
Z
Z
B
DE
DI
DE
DI
120Ω
120Ω
D
Y
Z
Y
B
A
Y
Z
R
A
A
R
D
D
DI
B
R
RE
RO
DE RE RO
DI
HWD489
HWD491
DE RE RO
NOTE: RE AND DE ON HWD489/HWD491 ONLY.
Figure 22. HWD488–HWD491 Full-Duplex RS-485 Network
Isolated RS-485
For isolated RS-485 applications, see the HWD253 and
HWD1480 data sheets.
HWD488–HWD491
A
RO
RE
DE
R
120Ω
DATA IN
120Ω
DATA OUT
B
Z
DI
D
Y
NOTE: RE AND DE ON HWD489/HWD491 ONLY.
Figure 23. Line Repeater for HWD488–HWD491
14
Low-Power, Slew-Rate-Limited
RS-485/RS-422 Transceivers
_______________Ordering Information
PART
TEMP. RANGE
__Ordering Information (continued)
PIN-PACKAGE
HWD481CPA
0°C to +70°C
8 Plastic DIP
HWD481CSA
0°C to +70°C
8 SO
HWD481CUA
0°C to +70°C
8 µMAX
HWD481C/D
0°C to +70°C
Dice*
HWD481EPA
-40°C to +85°C
8 Plastic DIP
HWD481ESA
HWD481MJA
HWD483CPA
-40°C to +85°C
-55°C to +125°C
0°C to +70°C
8 SO
8 CERDIP
8 Plastic DIP
HWD483CSA
0°C to +70°C
HWD483CUA
HWD483C/D
HWD483EPA
HWD483ESA
HWD483MJA
HWD485CPA
HWD485CSA
HWD485CUA
HWD485C/D
HWD485EPA
HWD485ESA
HWD485MJA
HWD487CPA
HWD487CSA
HWD487CUA
HWD487C/D
HWD487EPA
HWD487ESA
HWD487MJA
HWD488CPA
HWD488CSA
HWD488CUA
HWD488C/D
HWD488EPA
HWD488ESA
HWD488MJA
HWD489CPD
HWD489CSD
HWD489C/D
HWD489EPD
HWD489ESD
HWD489MJD
0°C to +70°C
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
-55°C to +125°C
0°C to +70°C
0°C to +70°C
0°C to +70°C
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
-55°C to +125°C
0°C to +70°C
0°C to +70°C
0°C to +70°C
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
-55°C to +125°C
0°C to +70°C
0°C to +70°C
0°C to +70°C
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
-55°C to +125°C
0°C to +70°C
0°C to +70°C
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
-55°C to +125°C
PART
HWD490CPA
HWD490CSA
HWD490CUA
HWD490C/D
HWD490EPA
HWD490ESA
HWD490MJA
HWD491CPD
HWD491CSD
HWD491C/D
HWD491EPD
HWD491ESD
HWD491MJD
HWD1487CPA
HWD1487CSA
HWD1487CUA
HWD1487C/D
HWD1487EPA
HWD1487ESA
HWD1487MJA
8 SO
8 µMAX
Dice*
8 Plastic DIP
8 SO
8 CERDIP
8 Plastic DIP
8 SO
8 µMAX
Dice*
8 Plastic DIP
8 SO
8 CERDIP
8 Plastic DIP
8 SO
8 µMAX
Dice*
8 Plastic DIP
8 SO
8 CERDIP
8 Plastic DIP
8 SO
8 µMAX
Dice*
8 Plastic DIP
8 SO
8 CERDIP
14 Plastic DIP
14 SO
Dice*
14 Plastic DIP
14 SO
14 CERDIP
TEMP. RANGE
0°C to +70°C
0°C to +70°C
0°C to +70°C
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
-55°C to +125°C
0°C to +70°C
0°C to +70°C
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
-55°C to +125°C
0°C to +70°C
0°C to +70°C
0°C to +70°C
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
-55°C to +125°C
PIN-PACKAGE
8 Plastic DIP
8 SO
8 µMAX
Dice*
8 Plastic DIP
8 SO
8 CERDIP
14 Plastic DIP
14 SO
Dice*
14 Plastic DIP
14 SO
14 CERDIP
8 Plastic DIP
8 SO
8 µMAX
Dice*
8 Plastic DIP
8 SO
8 CERDIP
* Contact factory for dice specifications.
_________________Chip Topographies
HWD481/HWD483/HWD485/HWD487/HWD1487
V CC
N.C.
RO
N.C.
RE
B
DE
A
DI
GND
0.080"
(2.032mm)
15
0.054"
(1.372mm)
Low-Power, Slew-Rate-Limited
RS-485/RS-422 Transceivers
_____________________________________________Chip Topographies (continued)
HWD488/HWD490
HWD489/HWD491
V CC
V CC
B
N.C.
0.054"
Z
(1.372mm)
RE
Y
DI
B
Z
DE
N.C.
DI
A
RO
A
RO
Y
GND
GND
0.080"
(2.032mm)
0.080"
(2.032mm)
TRANSISTOR COUNT: 248
SUBSTRATE CONNECTED TO GND
16
0.054"
(1.372mm)
Low-Power, Slew-Rate-Limited
RS-485/RS-422 Transceivers
Package Information
DIM
A
A1
B
C
e
E
H
L
N
E
H
INCHES
MILLIMETERS
MAX
MIN
0.069
0.053
0.010
0.004
0.014
0.019
0.007
0.010
0.050 BSC
0.150
0.157
0.228
0.244
0.016
0.050
MAX
MIN
1.35
1.75
0.10
0.25
0.35
0.49
0.19
0.25
1.27 BSC
3.80
4.00
5.80
6.20
0.40
1.27
VARIATIONS:
1
INCHES
TOP VIEW
DIM
D
D
D
MIN
0.189
0.337
0.386
MAX
0.197
0.344
0.394
MILLIMETERS
MIN
4.80
8.55
9.80
MAX
5.00
8.75
10.00
N MS012
8
AA
14
AB
16
AC
D
A
B
e
C
0∞-8∞
A1
L
FRONT VIEW
SIDE VIEW
TITLE:
PACKAGE OUTLINE, .150" SOIC
17
Low-Power, Slew-Rate-Limited
RS-485/RS-422 Transceivers
Package Information (continued)
.
4X S
8
E
ÿ 0.50±0.1
8
INCHES
DIM
A
A1
A2
b
H
c
D
e
E
H
0.6±0.1
1
L
1
α
0.6±0.1
S
BOTTOM VIEW
D
MIN
0.002
0.030
MAX
0.043
0.006
0.037
0.014
0.010
0.007
0.005
0.120
0.116
0.0256 BSC
0.120
0.116
0.198
0.188
0.026
0.016
0∞
6∞
0.0207 BSC
MILLIMETERS
MAX
MIN
0.05
0.75
1.10
0.15
0.95
0.25
0.36
0.13
0.18
2.95
3.05
0.65 BSC
2.95
3.05
4.78
5.03
0.41
0.66
0∞
6∞
0.5250 BSC
TOP VIEW
A1
A2
e
FRONT VIEW
A
c
b
α
L
SIDE VIEW
PROPRIETARY INFORMATION
TITLE:
PACKAGE OUTLINE, 8L uMAX/uSOP
18
Low-Power, Slew-Rate-Limited
RS-485/RS-422 Transceivers
Package Information (continued)
implied.
© 200
19
Chengdu Sino Microelectronics System Co.,Ltd
(Http://www.csmsc.com)
Headquarters of CSMSC:
Beijing Office:
Address: 2nd floor, Building D,
Science & Technology
Industrial Park, 11 Gaopeng
Avenue, Chengdu High-Tech
Zone,Chengdu City, Sichuan
Province, P.R.China
PC: 610041
Tel: +86-28-8517-7737
Fax: +86-28-8517-5097
Address: Room 505, No. 6 Building,
Zijin Garden, 68 Wanquanhe
Rd., Haidian District,
Beijing, P.R.China
PC: 100000
Tel: +86-10-8265-8662
Fax: +86-10-8265-86
Shenzhen Office:
Address: Room 1015, Building B,
Zhongshen Garden,
Caitian Rd, Futian District,
Shenzhen, P.R.China
PC: 518000
Tel : +86-775-8299-5149
+86-775-8299-5147
+86-775-8299-6144
Fax: +86-775-8299-6142
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