DATASHEET
ISL8487E, ISL81487L, ISL81487E
±15kV ESD Protected, 1/8 Unit Load, 5V, Low Power, High Speed or Slew Rate
Limited RS-485/RS-422 Transceivers
FN6051
Rev.8.00
Sep 20, 2018
The ISL8487E, ISL81487L, and ISL81487E RS-485/RS-422
devices are ESD protected, fractional unit load (UL),
Features
• RS-485 I/O pin ESD protection . . . . . . . . . . . ±15kV HBM
- Class 3 ESD level on all other pins . . . . . . . >7kV HBM
BiCMOS, 5V powered, single transceivers that meet both
the RS-485 and RS-422 standards for balanced
communication. Each driver output/receiver input is
protected against ±15kV ESD strikes without latch-up. Unlike
competitive devices, this device family is specified for 10%
tolerance supplies (4.5V to 5.5V).
• Fractional unit load allows up to 256 devices on the bus
• Specified for 10% tolerance supplies
• High data rate version (ISL81487E). . . . . . . up to 5Mbps
• Slew rate limited versions for error free data
transmission (ISL8487E, ISL81487L) . . . . .up to 250kbps
All devices present a 1/8 unit load to the RS-485 bus, which
allows up to 256 transceivers on the network for large node
count systems (for example, process automation and remote
meter reading systems). In a remote utility meter reading
system, individual utility meter readings (in apartments, for
example) are routed to a concentrator with an RS-485
network, so the high allowed node count minimizes the
number of repeaters required to network all the meters. Data
for all meters is then read out from the concentrator from a
single access port or a wireless link.
• Low current shutdown mode (except ISL81487E) . . . 0.5µA
• Low quiescent supply current:
- ISL8487E, ISL81487L . . . . . . . . . . . 145µA (maximum)
- ISL81487E . . . . . . . . . . . . . . . . . . . . 420µA (maximum)
• -7V to +12V common mode input voltage range
• Three state Rx and Tx outputs
• 30ns propagation delays, 5ns skew (ISL81487E)
• Half duplex pinouts
Slew rate limited drivers on the ISL8487E and ISL81487L
reduce EMI and minimize reflections from improperly
terminated transmission lines or unterminated stubs in
multidrop and multipoint applications. Data rates up to
250kbps are achievable with these devices.
• Operate from a single +5V supply (10% tolerance)
• Current limiting and thermal shutdown for driver overload
protection
Data rates up to 5Mbps are achievable by using the
ISL81487E, which features higher slew rates.
• Pin compatible replacements for: MAX487E, (ISL8487E);
LTC1487, ADM1487 (ISL81487L); MAX1487E, ST485ER
(ISL81487E)
The receiver (Rx) inputs feature a “fail-safe if open” design,
which ensures a logic high Rx output if Rx inputs are floating.
• Pb-free plus anneal available (RoHS compliant)
The driver (Tx) outputs are short-circuit protected, even for
voltages exceeding the power supply voltage. Additionally,
on-chip thermal shutdown circuitry disables the Tx outputs to
prevent damage if power dissipation becomes excessive.
Applications
• High node count networks
• Automated utility meter reading systems
• Factory automation
The half duplex devices multiplex the Rx inputs and Tx
outputs to allow transceivers with Rx and Tx disable
functions in 8 lead packages.
• Security networks
• Building environmental control systems
• Industrial/process control networks
Related Literature
For a full list of related documents, visit our website:
• ISL8487E, ISL81487L, and ISL81487E product pages
TABLE 1. SUMMARY OF FEATURES
PART
NUMBER
HALF/FULL
DUPLEX
NO. OF DEVICES
ALLOWED ON BUS
DATA RATE SLEW RATE
RECEIVER/
DRIVER ENABLE?
QUIESCENT LOW POWER
PIN
(Mbps)
0.25
0.25
5
LIMITED?
I
(A) SHUTDOWN? COUNT
CC
120
ISL8487E
ISL81487L
ISL81487E
Half
Half
Half
256
256
256
Yes
Yes
Yes
Yes
Yes
Yes
No
8
8
8
Yes
120
350
No
FN6051 Rev.8.00
Sep 20, 2018
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