MAX485ESA+ - 5V RS-485/RS-422 Transceiver, 2.5Mbps, SOIC-8
MPN: MAX485ESA+ ✓ AktifMAX485ESA+ Ringkasan
What is an RS-485/RS-422 transceiver? An RS-485 transceiver (TIA/EIA-485) is a differential line driver/receiver IC that converts a single-ended TTL/CMOS logic signal into a balanced differential signal suitable for transmission over twisted-pair cabling. RS-485 transceivers belong to the broader physical-layer IC family inside Interface ICs, which also includes RS-232, CAN, and I2C transceivers. The half-duplex variant shares one differential pair between driver and receiver, reducing cable cost for bidirectional buses such as Profibus, Modbus RTU, and DMX512.
Key features of the MAX485ESA+ include a 1/8 unit-load input impedance (allowing up to 256 transceivers on a single bus), driver short-circuit current limiting, and thermal-shutdown protection that places the driver outputs into a high-impedance state. The receiver includes a fail-safe function that guarantees a logic-high output when the differential input is floating, shorted, or terminated but idle. Industry-standard SOIC-8 pinout and 5 V operation make the part a drop-in upgrade or replacement for legacy Maxim/Intersil RS-485 designs.
Internally, the driver uses a slew-rate-limited output stage to reduce EMI and reflections on unterminated cables, while the receiver incorporates hysteresis and an input filter to reject common-mode noise. The common-mode input voltage range extends from -7 V to +12 V relative to ground, supporting long cable runs with significant ground potential differences between nodes.
Typical applications include industrial field-bus networks (Modbus, Profibus, BACnet), building automation, HVAC controllers, motor-control command links, point-of-sale terminals, and multidrop RS-485 utility metering. Designers select the MAX485ESA+ when they need a proven, second-source-friendly 5 V half-duplex transceiver with long-term availability.
When designing with this part, place 120 Ω termination resistors only at the two physical ends of the bus to avoid loading the drivers. Use a 100 nF decoupling capacitor placed within 5 mm of the VCC pin, and route the A/B differential traces with controlled 100 Ω differential impedance and ground-referenced return paths.
This page synthesizes distributor pricing, drop-in compatible alternatives (including the SN75176B and SP485EN-L/TR families), and practical design notes that go beyond the bare datasheet, helping engineers select and source the right transceiver faster.
Pilihan pengganti yang segera untuk MAX485ESA+ — sama paket, pin-pin kompatibel. Bahagian paket yang berbeza memerlukan kerja ulang PCB diasingkan.
Varietas dalam siri ini
Model serupa yang kompatibel dengan pengganti yang segera MAX485ESA+ (sama faktor bentuk dan kaki) — berbeza dalam Package, Data Rate, Supply Voltage, RoHS Status, Operating Temperature.
MAX485CSA+
✅ Masuk Drop-InHubungi untuk harga
Lihat Datasheet →MAX485ESA+T
✅ Masuk Drop-InHubungi untuk harga
Lihat Datasheet →MAX485EESA+
✅ Masuk Drop-In ⚠️ Spesifikasi Tidak DisahkanHubungi untuk harga
Lihat Datasheet →SN75176BDR
✅ Masuk Drop-InHubungi untuk harga
Lihat Datasheet →SP485EN-L/TR
✅ Masuk Drop-In📋 Alternatif rujukan (tidak dalam katalog)
ST485ECDR
✅ Masuk Drop-In📋 Alternatif rujukan (tidak dalam katalog)
ISL8485ECBZ
✅ Masuk Drop-In📋 Alternatif rujukan (tidak dalam katalog)
MAX485ESA+ Spesifikasi
| Fungsi | Transceiver |
| Protocol | RS-422, RS-485 |
| Number of Drivers/Receivers | 1/1 |
| Duplex | Half |
| Tegangan Pemberi Arus | 4.75 V to 5.25 V (5 V nominal) |
| Kadar Data | 2.5 Mbps |
| Supply Current (unloaded) | 120 µA to 500 µA |
| Receiver Hysteresis | 70 mV (typ) |
| Common-Mode Input Range | -7 V to +12 V |
| Differential Input Threshold (V_TH) | -0.2 V min / +0.2 V max |
| ESD Protection (HBM, driver output) | ±15 kV (per datasheet) |
| Unit Load | 1/8 (up to 256 transceivers on bus) |
| Suhu Operasi | -40 °C to +85 °C |
| Kemasan | 8-SOIC (SOIC-8) |
| Jenis Pemasangan | Surface Mount |
| Status RoHS | Compliant (per Maxim/ADI datasheet suffix '+') |
Konfigurasi Pin MAX485ESA+
| Pin 1 | RO — Receiver output (push-pull TTL/CMOS) |
| Pin 2 | RE — Receiver output enable (active-low; tie low to enable RO) |
| Pin 3 | DE — Driver output enable (active-high; tie high to drive DI onto A/B) |
| Pin 4 | DI — Driver input (TTL/CMOS) |
| Pin 5 | GND — Ground |
| Pin 6 | A — Non-inverting differential driver output / receiver input |
| Pin 7 | B — Inverting differential driver output / receiver input |
| Pin 8 | VCC — +5 V supply |
Aplikasi Biasa
MAX485ESA+ patut untuk 7 aplikasis: Industrial Modbus RTU Field-Bus, Building Automation and HVAC Control, DMX512 Stage Lighting Control, Point-of-Sale (POS) and EFT Terminals, Utility Metering (AMI) Networks, Solar Inverter and Motor-Drive Command Links, Security and Access-Control Panels.
Industrial Modbus RTU Field-Bus
The MAX485ESA+ is a long-standing choice for Modbus RTU networks over twisted-pair cable. Its 1/8 unit-load input impedance allows up to 256 nodes on a single bus, well beyond the TIA/EIA-485 32-unit-load minimum, while the -7 V to +12 V common-mode range tolerates ground-potential differences between factory-floor cabinets. The fail-safe receiver output guarantees a defined logic-high when the bus is idle, satisfying Modbus' t1.5 inter-character timing. Placed at every PLC, sensor, and inverter node with 120 Ω termination only at the two physical ends, the part delivers reliable 2.5 Mbps communication in electrically noisy industrial environments.
Disebarkan
Building Automation and HVAC Control
BACnet MS-TP and many proprietary HVAC control buses rely on RS-485 half-duplex transceivers such as the MAX485ESA+. The part's 120 µA to 500 µA unloaded supply current allows battery-backed thermostat and controller designs to meet strict standby-power budgets, while its 5 V single-supply operation simplifies integration with legacy HVAC boards. The slew-rate-limited driver reduces emissions that could disturb sensitive temperature-sensor front-ends, and the SOIC-8 footprint eases retrofitting into compact CR-1015 / wall-mount enclosures.
Disebarkan
DMX512 Stage Lighting Control
DMX512-A is an RS-485-based lighting-control protocol that runs on a single half-duplex differential pair at 250 kbps, well within the MAX485ESA+'s 2.5 Mbps capability. The 1/8 unit-load input is essential for daisy-chaining 32 fixtures (the maximum DMX-512 spec) plus the controller and any repeaters. The receiver's fail-safe behavior prevents lamps from drifting to mid-intensity when the bus is idle, and the robust -7 V to +12 V common-mode range protects fixtures against ground-loops when long cable runs span large venues.
Disebarkan
Point-of-Sale (POS) and EFT Terminals
Multi-drop RS-485 networks are common inside POS terminals for connecting card readers, customer displays, and cash-drawer triggers. The MAX485ESA+ draws only 120 µA in shutdown, enabling battery-powered mobile POS devices to meet Energy Star standby targets. Its industry-standard SOIC-8 pinout allows PCB reuse across product variants, and compliance with TIA/EIA-485 ensures interoperability with third-party terminals. The ±15 kV HBM ESD protection (on the E variant) helps pass IEC 61000-4-2 air-discharge testing at the connector.
Disebarkan
Utility Metering (AMI) Networks
Advanced Metering Infrastructure (AMI) often uses RS-485 multidrop to read electricity, water, and gas meters from a concentrator. With the MAX485ESA+, a single concentrator can poll up to 256 meters, eliminating the need for cascaded repeaters. The part's wide common-mode range tolerates ground potential differences between meter installations, and its thermal-shutdown output protection prevents damage from short-circuited cable runs during installation. The 1/8 unit load is a key enabler for dense meter banks.
Disebarkan
Solar Inverter and Motor-Drive Command Links
Solar inverters and AC motor drives frequently expose a service/debug RS-485 port for parameter setting and telemetry. The MAX485ESA+ provides a robust 5 V half-duplex interface on the low-voltage control board, isolated from the high-voltage DC bus by an isolation barrier. Its fail-safe receiver ensures a defined logic state during firmware boot, and the 2.5 Mbps capability supports fast firmware-update transfers. Inside the inverter, the part also bridges power-stage DSPs to external BMS or PLC controllers.
Disebarkan
Security and Access-Control Panels
Access-control panels use multi-drop RS-485 to connect card readers, electric strikes, and door sensors to a central controller over hundreds of meters of cable. The MAX485ESA+'s -7 V to +12 V common-mode range rejects ground shifts between buildings, while the 1/8 unit-load input supports dense reader-per-door topologies. Fail-safe receiver operation prevents mis-coded 'door open' commands when bus contention occurs during installer configuration.
Disebarkan
Ringkasan Produk Disebarkan
Data referensi kejuruteraan untuk MAX485ESA+ — perbandingan, panduan rancangan, dan maklumat kesediaan
Panduan Pilihan
Perbandingan dengan Gantian
| Parametr | Produk Ini | MAX485CSA+ | SN75176BDR | SP485EN-L/TR | ST485ECDR | ISL8485ECBZ |
|---|---|---|---|---|---|---|
| Brand | Analog Devices (Maxim) | Analog Devices (Maxim) | Texas Instruments | MaxLinear | STMicroelectronics | Renesas Electronics |
| Package | SOIC-8 | SOIC-8 - same | SOIC-8 - same | SOIC-8 - same | SOIC-8 - same | SOIC-8 - same |
| Supply Voltage | 5 V (4.75 V - 5.25 V) | 5 V - same | 5 V - same | 5 V - same | 5 V - same | 5 V - same |
| Data Rate | 2.5 Mbps | 2.5 Mbps | 10 Mbps | 10 Mbps | 2.5 Mbps | 2.5 Mbps |
| Unit Load | 1/8 (256 nodes) | 1/8 | 1 | 1/8 to 1 | 1/8 | 1/8 |
| Duplex | Half | Half | Half | Half | Half | Half |
| ESD Protection (HBM) | ±15 kV (E variant) | ±15 kV (E variant) | ±15 kV | ±15 kV | ±15 kV | ±15 kV |
| Operating Temperature | -40 °C to +85 °C | 0 °C to +70 °C | 0 °C to +70 °C | -40 °C to +85 °C | -40 °C to +85 °C | -40 °C to +85 °C |
| Approx. Unit Price (1k) | USD 1.05 | USD 1.05 | USD 0.55 | USD 0.45 | USD 0.60 | USD 1.20 |
Penyeberangsung Jelas
- Highest available node count on a single bus (vsSN75176BDR)
- Industry-standard pinout with broadest cross-brand second-sourcing (vsSP485EN-L/TR)
- Long-term availability through active Maxim/ADI catalog (vsISL8485ECBZ)
Catatan Desain
Place a 100 nF X7R decoupling capacitor within 5 mm of the VCC pin (pin 8), with the ground via stitching on pin 5. Route the A/B differential traces as a 100 Ω controlled-impedance pair with constant spacing and a continuous ground-reference plane below; skew between A and B should not exceed 1 mm to preserve common-mode rejection above 1 MHz.
Do not place 120 Ω termination resistors at every node; only the two physical ends of the bus should be terminated. Mid-bus termination divides the bus impedance, attenuates the signal, and can cause reflections that break Modbus communication. Also avoid star topologies - T-stubs longer than one-tenth of the rise time introduce reflections that limit cable length at 2.5 Mbps.
Estimated: when the driver is differentially short-circuited, the MAX485ESA+ dissipates up to VIN × |I_osc| for the duration of the fault. The internal thermal-shutdown circuit typically triggers at ~150 °C junction temperature; verify this in the manufacturer datasheet for the specific lot, and derate the SOIC-8 θ_JA of ~170 °C/W with adequate copper pour on the GND pin to keep the junction within limits.
For cable runs above 100 m at 2.5 Mbps, add a series 10 Ω resistor on each of the A/B driver outputs and a 100 nF capacitor between A and B to damp high-frequency overshoot. The MAX485ESA+ slew-rate-limited output stage reduces EMI but does not eliminate ringing on unterminated stubs.
Keep the logic-side traces (RO, RE, DE, DI) routed on the inner PCB layer above a solid ground plane, separated from the bus-side A/B traces by a ground moat if the design integrates both on the same board. Adding a TVS diode such as the SMAJ12CA across the A/B pair dramatically improves IEC 61000-4-2 contact-discharge performance.
Maklumat Kesediaan
RoHS and lead-free status confirmed by Maxim/ADI ordering suffix '+'. Industry-grade operating temperature of -40 °C to +85 °C - this is not an AEC-Q100 automotive-grade part.
