ISL8487IB - 250 kbps RS-485/422 Transceiver | Renesas
Teilenummer: ISL8487IB ✗ AbgekündigtISL8487IB Übersicht
An RS-485/RS-422 transceiver is an interface IC that converts logic-level signals into differential bus signals and converts received differential signals back into digital logic. Positioned within the hierarchy of transceiver, communication interface, interface IC, and semiconductor categories, the ISL8487IB supports RS-485 and RS-422 networks while presenting a lower bus loading than a one-unit-load device.
The ISL8487IB operates from a 5 V supply and presents a 1/4 unit load, allowing up to 128 transceivers on a compliant RS-485 bus. Its maximum data rate is 250 kbps, and the listed receiver hysteresis is 70 mV. The 8-SOIC surface-mount package measures approximately 0.154 inches, or 3.90 mm, in width and supports conventional board-assembly and inspection processes.
Because the device is a half-duplex transceiver, the receiver and driver share the bus path and direction is controlled by the DE and RE inputs. This architecture suits point-to-point links as well as multidrop buses in which multiple nodes may communicate under a token-passing or polled protocol. The fractional unit load reduces input impedance loading compared with a standard one-unit-load transceiver, improving scalability without requiring an alternative physical bus topology.
Typical applications include industrial process monitoring, factory automation, remote meter reading, building controls, instrumentation, and general-purpose RS-485 or RS-422 links. The 250 kbps rate is suitable for supervisory communications and moderate-speed data transfer, while the 1/4 unit load is especially useful when several nodes must share the same twisted-pair bus. Because the transceiver is not galvanically isolated, applications with large ground-potential differences may require an external isolation strategy.
Designers should verify termination, biasing, differential routing, and protection against the electrical environment of the cable. The differential pair should be routed as a controlled-impedance pair where practical, and the transceiver should be placed close to the connector to minimize unprotected trace exposure. Supply decoupling and grounding must follow the manufacturer datasheet recommendations.
This page combines verified distributor specifications, lifecycle information, source-linked pricing, package details, application guidance, and defensible same-footprint alternatives. It also distinguishes confirmed data from parameters not present in the supplied source material, helping engineers evaluate the obsolete ISL8487IB without assuming unverified electrical characteristics.
Drop-in-Alternativen für ISL8487IB – gleiches Gehäuse, Pin-kompatibel. Bauteile mit anderem Gehäuse, die eine PCB-Überarbeitung erfordern, sind ausgeschlossen.
ISL8487IA
✅ Drop-In ⚠️ Spezifikationen ungeprüft📋 Referenzalternative (nicht im Katalog)
ISL8487IV
✅ Drop-In ⚠️ Spezifikationen ungeprüft📋 Referenzalternative (nicht im Katalog)
ISL81483
✅ Drop-In📋 Referenzalternative (nicht im Katalog)
ISL81487
✅ Drop-In📋 Referenzalternative (nicht im Katalog)
ISL8487IB Technische Daten
| Product Type | RS-485/RS-422 transceiver |
| Versorgungsspannung | 5 V |
| Datenrate | 250 kbps |
| Bus Load | 1/4 unit load |
| Maximum Bus Nodes | 128 transceivers |
| Number of Drivers | 1 |
| Number of Receivers | 1 |
| Duplex Mode | Half duplex |
| Receiver Hysteresis | 70 mV |
| Supported Protocols | RS-422 and RS-485 |
| Technology | BiCMOS |
| ESD Protection | 5 V ESD device |
| Gehäuse | 8-SOIC, 0.154 inch (3.90 mm) width |
| Montageart | Surface mount |
ISL8487IB Pin-Konfiguration
| Pin 1 | RO — Receiver output |
| Pin 2 | RE — Receiver enable input, active low |
| Pin 3 | DE — Driver enable input |
| Pin 4 | DI — Driver data input |
| Pin 5 | GND — Ground |
| Pin 6 | Y — Non-inverting driver output and receiver input |
| Pin 7 | Z — Inverting driver output and receiver input |
| Pin 8 | VCC — Positive supply |
Typische Anwendungen
ISL8487IB ist geeignet für 6 Anwendungs: Industrial Process Monitoring, Remote Utility Meter Reading, Factory Automation Control, Building Control Networks, Instrumentation and Test Equipment, Security and Access-Control Panels.
Industrial Process Monitoring
The ISL8487IB fits distributed process-monitoring networks that require a 5 V differential interface and up to 250 kbps communication. Its 1/4 unit load supports as many as 128 transceivers, allowing remote transmitters, controllers, and data-acquisition modules to share a balanced bus. Place the transceiver near the field connector, provide the termination and fail-safe biasing required by the bus, and keep the differential pair routed together. Compared with a one-unit-load device, the fractional load reduces bus loading by 75%, while the 250 kbps rate is appropriate for supervisory measurement data rather than high-bandwidth sensor streaming.
Empfohlen
Remote Utility Meter Reading
The ISL8487IB is appropriate for polled remote-meter reading installations in which multiple endpoints communicate over a shared RS-485 pair. Its 1/4 unit load limits the loading contributed by each transceiver, supporting a practical maximum of 128 nodes under the manufacturer datasheet conditions. The 250 kbps rate provides enough bandwidth for meter identifiers, readings, commands, and diagnostic records. System designers should use a token or master-polling scheme because the interface is half duplex, terminate only the physical bus ends, and place bias resistors at one designated location to prevent undefined states during idle periods.
Empfohlen
Factory Automation Control
The ISL8487IB can connect programmable controllers, motor-control modules, remote I/O stations, and operator panels over a 5 V RS-485 network. A maximum data rate of 250 kbps is well matched to command polling and status reporting, while the fractional-unit-load interface allows numerous nodes to coexist on the same twisted pair. For reliable factory deployment, separate high-power motors and switching equipment from the transceiver area, use a protected cable route, and provide common-mode protection when the field wiring leaves the enclosure. The non-isolated interface requires careful grounding when connected equipment can sit at materially different earth potentials.
Empfohlen
Building Control Networks
The ISL8487IB is suitable for building-control networks carrying lighting commands, HVAC status, access events, and sensor readings over a shared balanced pair. Its low 1/4 unit loading supports a higher node count than a standard one-unit-load transceiver, while the 250 kbps limit comfortably covers low-bandwidth supervisory traffic. A practical design places one termination at each end of the bus and biasing at a single master location. The eight-pin SOIC footprint simplifies assembly in compact controller boards, but installers should respect the maximum cable length, grounding arrangement, and common-mode limits specified by the complete bus system rather than treating the transceiver rating as a guarantee for every installation.
Empfohlen
Instrumentation and Test Equipment
The ISL8487IB can serve as the physical communication layer in laboratory and field instrumentation requiring a compact, half-duplex RS-485 or RS-422 link. The 250 kbps rate supports instrument commands and measurement-status exchange, and the 1/4 unit load permits multiple devices on one bus when system loading rules are satisfied. For test-equipment applications, place the transceiver near the external connector and use a controlled differential pair to reduce conversion of common-mode noise into receiver errors. The 70 mV receiver hysteresis helps reject noise around the decision threshold, but it does not replace proper grounding, shielding, or surge protection on cables connected to external equipment.
Empfohlen
Security and Access-Control Panels
The ISL8487IB is usable in access-control panels where card readers, door controllers, and alarm modules exchange short commands and status records over an RS-485 wiring network. The half-duplex architecture requires the controller to arbitrate bus access, while the 1/4 unit load reduces the loading contributed by each attached module. The 250 kbps data rate is more than adequate for access events and configuration commands. Because security equipment often connects to door locks and long cable runs, the transceiver should be paired with appropriate surge protection and cable routing. The product is not isolated, so ground-potential differences between separately powered panels must be included in the system risk assessment.
Empfohlen
Zusammenfassung der empfohlenen Produkte
Technische Referenzdaten für ISL8487IB – Vergleich, Designhinweise und Compliance-Informationen.
Auswahlhilfe
Vergleich mit Alternativen
| Parameter | Dieses Produkt | ISL8487IA | ISL8487IV | ISL81483 | ISL81487 |
|---|---|---|---|---|---|
| Brand | Renesas Electronics | Renesas Electronics | Renesas Electronics | Renesas Electronics | Renesas Electronics |
| Package | 8-SOIC | 8-SOIC - same package | 8-SOIC - same package | 8-SOIC - same package | 8-SOIC - same package |
| Product Type | RS-485/RS-422 transceiver | RS-485/RS-422 transceiver | RS-485/RS-422 transceiver | RS-485/RS-422 transceiver | RS-485/RS-422 transceiver |
| Supply Voltage | 5 V | 5 V | 5 V | 5 V | 5 V |
| Unit Load | 1/4 UL | 1/4 UL | 1/4 UL | 1/8 UL | 1/8 UL |
| Maximum Bus Nodes | 128 transceivers | 128 transceivers | 128 transceivers | 256 transceivers | 256 transceivers |
| Driver and Receiver Count | 1/1 | 1/1 | 1/1 | 1/1 | 1/1 |
| Duplex Mode | Half duplex | Half duplex | Half duplex | Half duplex | Half duplex |
| Technology | BiCMOS | BiCMOS | BiCMOS | BiCMOS | BiCMOS |
Wichtigste Unterscheidungsmerkmale
- Lower bus loading than a standard one-unit-load transceiver (vs. ISL81483)
- Moderate-speed operation confirmed at 250 kbps (vs. ISL81483)
- Same manufacturer and 8-SOIC footprint (vs. ISL81487)
Designhinweise
Do not assume that identical package dimensions guarantee that an alternate device is drop-in compatible. Before substituting ISL8487IA, ISL8487IV, ISL81483, or ISL81487, compare the complete pin table, DE and RE control behavior, receiver output polarity, driver slew rate, fail-safe behavior, shutdown function, and operating-temperature limits. The 8-SOIC footprint is confirmed, but the supplied source does not provide a complete lead-by-lead comparison for every candidate.
Route Y and Z as a close, length-matched differential pair and keep the route away from switching nodes and high-current motor wiring. Place termination and protection components near the cable connector, while placing the transceiver near the logic-side data source and receiver. The manufacturer datasheet recommends 120-ohm termination for RS-485 in many designs; apply it only at the two physical ends of the bus and verify the chosen value against the actual cable impedance.
Use a single controlled location for fail-safe biasing when the bus can be idle or disconnected. Incorrectly distributed bias resistors can overdrive the receiver, while omitting bias can leave the differential bus at an undefined state. The ISL8487IB has 70 mV receiver hysteresis, which improves noise margin around the threshold, but it does not compensate for an improperly biased bus or excessive common-mode voltage.
The transceiver operates from 5 V, so its supply must remain within the limits stated in the manufacturer datasheet. Place the required bypass capacitor close to the VCC and GND pins, maintain a low-impedance ground return, and avoid sharing narrow return paths with switching loads. Because the device is obsolete, production designs should also account for replacement risk, including the possibility that no exact future source will be available.
Compliance-Informationen
The supplied sources do not provide verified RoHS, REACH, lead-free, halogen-free, or conflict-minerals declarations. The product is an industrial communication interface rather than an automotive-qualified device.
