MAX485ECPA+ - 1 Mbps RS-485/RS-422 Half-Duplex Transceiver | Maxim
Teilenummer: MAX485ECPA+ ✓ AktivMAX485ECPA+ Übersicht
An RS-485 transceiver is a differential line-interface IC inside the broader hierarchy of interface ICs -> differential line driver/receiver -> communications transceiver -> semiconductor. It converts a logic-level serial signal (DI) into a balanced differential pair on the A and B bus wires, and converts a differential bus voltage back into a logic-level receiver output (RO). Unlike a single-ended RS-232 transceiver, an RS-485 driver drives a balanced, floating differential pair, so common-mode noise is rejected and cables up to about 1200 metres at low data rates can be supported.
Key features of the MAX485ECPA+ include a limited-slew-rate driver that minimizes EMI and ground bounce on the bus, allowing operation without external slew-control resistors; short-circuit current limiting on the driver outputs; thermal shutdown for excessive power dissipation; and a low quiescent current design that supports low-power node designs. A shutdown (sleep) input is not present on this device, so the node stays enabled while powered, which simplifies bus management in fixed installations.
Technically, the MAX485ECPA+ is a single-channel half-duplink device: DE (driver enable) and /RE (receiver enable) are separate pins, so a design can transmit, receive, or disable the bus independently for fail-safe biasing. The driver is designed for a balanced network so that no additional termination or bias resistors are required on the driver side, although the bus must still be properly terminated at the two physical ends and biased at exactly one point if the transceiver's receiver thresholds require it.
Typical applications include industrial RS-485 multidrop buses, building automation and HVAC controllers, energy meters, inverters and solar trackers, security and access-control panels, and instrumentation links to remote sensors. The 8-pin PDIP package is preferred for leaded industrial equipment where through-hole assembly, hand soldering, and field replacement are required.
The main design consideration is ESD and surge coupling: although the internal protection is rated at ±15 kV on the bus pins, the ESD paths are only effective if the bus entry point is close to the transceiver, so a multi-layer board with a solid ground plane and short A/B traces is strongly preferred over a long unprotected stub.
This page consolidates distributor pricing, verified package and interface details, pin-compatible drop-in alternatives in the same PDIP-8 footprint, and practical RS-485 layout and termination guidance that are not collated on a single manufacturer page.
Drop-in-Alternativen für MAX485ECPA+ – gleiches Gehäuse, Pin-kompatibel. Bauteile mit anderem Gehäuse, die eine PCB-Überarbeitung erfordern, sind ausgeschlossen.
Varianten dieser Serie
Modelle derselben Serie, die drop-in-kompatibel sind mit MAX485ECPA+ (gleiche Bauform und Footprint) – abweichend in Package, RoHS Status, Mounting Type, Driver Count, ESD Protection.
MAX485CPA+
✅ Drop-InPreis auf Anfrage
Datenblatt ansehen →MAX485EPA+
✅ Drop-InPreis auf Anfrage
Datenblatt ansehen →MAX485EEPA+
✅ Drop-In ⚠️ Spezifikationen ungeprüftPreis auf Anfrage
Datenblatt ansehen →LTC485CN8#PBF
✅ Drop-In📋 Referenzalternative (nicht im Katalog)
SN75176
✅ Drop-InPreis auf Anfrage
Datenblatt ansehen →MAX485ECPA+ Technische Daten
| Transceiver Configuration | 1 driver / 1 receiver, half-duplex |
| Interface Standard | RS-485 / RS-422 differential |
| Versorgungsspannung | 5 V nominal (4.5 V to 5.5 V) |
| Maximum Data Rate | 1 Mbps (slew-rate-limited driver) |
| Driver Output Type | Differential, limited slew rate |
| ESD Protection | +/-15 kV on driver outputs and receiver inputs |
| Gehäuse | PDIP-8 (8-pin plastic DIP, through-hole) |
| Montageart | Through Hole |
| Enable Pins | DE (driver enable) and /RE (receiver enable, active-low), separate pins |
| Short-Circuit Protection | Yes, driver outputs are short-circuit current limited |
| Thermisches Abschalten | Yes, protects against excessive power dissipation |
| Quiescent Current Shutdown Pin | Not present on this device |
| RoHS-Status | Compliant (Maxim lead-free suffix '+') |
MAX485ECPA+ Pin-Konfiguration
| Pin 1 | RO — Receiver output (logic-level, non-inverting) |
| Pin 2 | /RE — Receiver enable, active-low |
| Pin 3 | DE — Driver enable, active-high |
| Pin 4 | DI — Driver input (logic-level data in) |
| Pin 5 | GND — Ground |
| Pin 6 | A — Non-inverting driver output / bus A |
| Pin 7 | B — Inverting driver output / bus B |
| Pin 8 | VCC — Positive supply, 5 V nominal |
Typische Anwendungen
MAX485ECPA+ ist geeignet für 6 Anwendungs: Industrial RS-485 Multidrop Bus, Building Automation and HVAC Controller, Energy Metering and Utility Data Collection, Solar Inverter and Energy Storage Telemetry, Industrial Sensor and Instrumentation Link, Access Control and Security Panels.
Industrial RS-485 Multidrop Bus
The MAX485ECPA+ fits factory-floor RS-485 multidrop networks because it combines a 1 Mbps slew-rate-limited driver, which suppresses EMI and ground bounce on long cables, with +/-15 kV ESD protection on the A and B bus pins, which tolerates electrostatic coupling when cables are routed through cabinets. It is used as a node transceiver on the 2-wire bus, with DE asserted for transmit and /RE asserted for receive, and separate enable pins let the node go high-impedance during idle so parallel nodes do not fight each other. The 8-pin PDIP package suits leaded industrial controllers where through-hole assembly and field replacement are required. Trade-off: at 1 Mbps the maximum practical cable length drops sharply, so for distances beyond about 10-50 m a lower-rate transceiver is preferable.
Empfohlen
Building Automation and HVAC Controller
In HVAC and building-automation controllers, the MAX485ECPA+ provides the physical layer for BACnet MS/TP or Modbus RTU field buses that link indoor units, dampers and rooftop units to a supervisory controller. The ±15 kV ESD rating on the driver outputs and receiver inputs is valuable because building wiring is often routed close to mains-derived circuits and long cable runs, where electrostatic transients are common. The transceiver's separate DE and /RE pins make it easy to implement fail-safe biasing so the bus sits in a defined state when the controller resets, while the 1 Mbps capability leaves ample margin for typical 9600 to 115200 baud building-bus traffic.
Empfohlen
Energy Metering and Utility Data Collection
The MAX485ECPA+ is widely used in utility-grade metering clusters where multiple energy meters daisy-chain onto an RS-485 bus back to a concentrator. Because the meters are frequently located in outdoor or semi-outdoor enclosures, the ±15 kV ESD protection is the decisive feature compared with the non-E MAX485CPA+, which lacks that rating on the bus pins. The device's half-duplex 1/1 architecture allows several meters to share the same pair of conductors, with DE and /RE used to claim the bus only during transmission. The PDIP-8 package suits meter manufacturers that still use leaded through-hole assembly for cost and rework reasons.
Empfohlen
Solar Inverter and Energy Storage Telemetry
Solar inverters, trackers and battery energy-management systems use the MAX485ECPA+ for the RS-485 link between the power-control board and remote monitoring or combiner boxes. The slew-rate-limited driver reduces radiated emissions, which matters when the same enclosure also contains high-power switching stages and the communication cable runs adjacent to power wiring. The ±15 kV ESD rating helps survive both factory handling and field-installed outdoor cabling. One design consideration is that the 8-pin PDIP device offers no shutdown or sleep pin, so the transceiver stays powered whenever the board is energized - acceptable in a mains-powered inverter but relevant if your design targets deep-sleep energy harvesting.
Empfohlen
Industrial Sensor and Instrumentation Link
The MAX485ECPA+ is used as the point-to-point differential link between an instrumentation board and remote sensors, meters or transducers over a twisted pair. RS-485 differential signaling rejects common-mode noise that would corrupt single-ended signals in industrial environments, and the MAX485ECPA+'s ESD-protected bus pins tolerate handling transients during installation and maintenance. For point-to-point RS-422 style links the same device is used with the driver outputs driving the pair and the receiver reading the remote end. Keep the bus terminated with 120 ohm at both physical ends and keep the ground reference within the common-mode range of the receivers - the exact common-mode limits should be confirmed in the manufacturer datasheet for your design.
Empfohlen
Access Control and Security Panels
Access-control readers, door controllers and video backhaul nodes in security systems typically terminate an RS-485 daisy chain, and the MAX485ECPA+ provides a rugged 1/1 node with +/-15 kV ESD protection suited to installations where readers are wired outside the enclosure. The device's independent DE and /RE enables allow a panel to keep its receiver active while its driver is disabled, which is the basis of standard fail-safe bus biasing with external resistors. The commercial 'C' temperature suffix should be checked against the expected enclosure temperature, and for outdoor or unheated cabinets an extended-temperature variant of the family is the safer choice.
Empfohlen
Zusammenfassung der empfohlenen Produkte
Technische Referenzdaten für MAX485ECPA+ – Vergleich, Designhinweise und Compliance-Informationen.
Auswahlhilfe
Vergleich mit Alternativen
| Parameter | Dieses Produkt | MAX485CPA+ | MAX485EPA+ | MAX485EEPA+ | LTC485CN8#PBF | SN75176 |
|---|---|---|---|---|---|---|
| Package | PDIP-8 (through-hole) | PDIP-8 - same | PDIP-8 - same | PDIP-8 - same | PDIP-8 - same | PDIP-8 - same |
| Brand | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated | Analog Devices (Linear Technology) | Texas Instruments |
| Transceiver Configuration | 1 driver / 1 receiver, half-duplex | 1 driver / 1 receiver, half-duplex | 1 driver / 1 receiver, half-duplex | 1 driver / 1 receiver, half-duplex | 1 driver / 1 receiver, half-duplex | 1 driver / 1 receiver, half-duplex |
| Maximum Data Rate | 1 Mbps | 1 Mbps | 1 Mbps | 1 Mbps | 1 Mbps class | 1 Mbps class |
| Supply Voltage | 5 V (4.5 V to 5.5 V) | 5 V | 5 V | 5 V | 5 V | 5 V |
| Short-Circuit / Thermal Protection | Short-circuit current limit and thermal shutdown | Short-circuit current limit and thermal shutdown | Short-circuit current limit and thermal shutdown | Short-circuit current limit and thermal shutdown | Short-circuit current limit and thermal shutdown | Short-circuit current limit |
Wichtigste Unterscheidungsmerkmale
- ESD-hardened bus pins in a through-hole package (vs. MAX485CPA+)
- Same DIP-8 footprint with industrial temperature option for lower cost (vs. LTC485CN8#PBF)
- Slew-rate-limited driver reduces EMI without external resistors (vs. SN75176)
Designhinweise
Keep the A and B traces short and route them as a tight differential pair over a continuous ground plane. The MAX485ECPA+ is intended to sit at the cable entry point of the board, not at the far end of a long internal trace - the +/-15 kV ESD rating is only effective if the protected pins are physically close to the connector. Use a multilayer board with an uninterrupted ground pour under the transceiver, and keep the transceiver ground connection short and via-stitched to the plane to minimise common-mode inductance.
Terminate the bus with 120 ohm resistors at the two physical ends only, and bias the bus at exactly one location if the receiver thresholds require defined idle state. Installing termination on every node is a classic RS-485 mistake that loads the driver and reduces differential voltage at high data rates. Also note that the MAX485ECPA+ has no shutdown pin - DE and /RE only disable the driver and receiver - so a bus node cannot be fully powered down while still being connected to the pair.
Separate the transceiver from noisy circuitry on the board: keep switching regulators, high-current relays and inductors away from the A/B pair, and avoid routing the bus traces underneath them. Because the MAX485E family uses a slew-rate-limited driver specifically to control EMI, adding large external capacitance on the bus or extremely sharp multiplexing of the DE pin can defeat that benefit. If the design needs galvanic isolation for a long or ground-potential-shifted link, add an isolation barrier such as ISO1211DR rather than relying on the cable alone.
The MAX485ECPA+ requires a clean 5 V rail; place a 0.1 uF bypass capacitor directly across pins 8 (VCC) and 5 (GND) and add 4.7 uF to 10 uF of bulk capacitance near the device. The transceiver draws low current in the enabled state but the bus driver adds significant dynamic current when transmitting, so a shared, weakly decoupled supply rail can inject noise onto adjacent analog or RF circuits on the same board. If several nodes share one board, decouple each transceiver locally rather than relying on a single system-level capacitor.
Compliance-Informationen
The '+' suffix denotes Maxim Integrated lead-free (RoHS-compliant) production. AEC-Q100 automotive qualification is not claimed for this part; REACH, halogen-free status and conflict-minerals declarations were not present in the retrieved sources and are therefore marked unknown rather than assumed.
