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.
________________________Applications
Low-Power RS-485 Transceivers
Low-Power RS-422 Transceivers
Level Translators
Transceivers for EMI-Sensitive Applications
Industrial-Control Local Area Networks
__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
Low-Power, Slew-Rate-Limited
RS-485/RS-422 Transceivers
______________________________________________________________Selection Table
HWD481
HWD483
HWD485
HWD487
HWD488
HWD489
HWD490
HWD491
HWD1487
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
Half
Half
Half
Half
Full
Full
Full
Full
Half
2.5
0.25
2.5
0.25
0.25
0.25
2.5
2.5
2.5
No
Yes
No
Yes
Yes
Yes
No
No
No
Yes
Yes
No
Yes
No
No
No
No
No
Yes
Yes
Yes
Yes
No
Yes
No
Yes
Yes
300
120
300
120
120
120
300
300
230
32
32
32
128
32
32
32
32
128
8
8
8
8
8
14
8
14
8
Ordering Information appears at end of data sheet.
1
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