MAX485ESA+ - 5V RS-485/RS-422 Transceiver, 2.5Mbps, SOIC-8
MPN: MAX485ESA+ ✓ فعالMAX485ESA+ جائزہ
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.
کے لیے ڈراپ اِن متبادل MAX485ESA+ — یکساں پیکیج، پن سے پن مطابقت پذیر۔ مختلف پیکیج والے پرزے جن کے لیے PCB دوبارہ کام درکار ہو، شامل نہیں ہیں۔
اس سیریز میں مختلف ورژن
اسی سیریز کے ماڈلز جو ڈراپ اِن مطابقت رکھتے ہیں MAX485ESA+ (یکساں فارم فیکٹر اور فٹ پرنٹ) — میں مختلف Package, Data Rate, Operating Temperature, Supply Voltage, RoHS Status.
MAX485CSA+
✅ ڈراپ-اِنقیمت کے لیے رابطہ کریں
ڈیٹا شیٹ دیکھیں →MAX485ESA+T
✅ ڈراپ-اِنقیمت کے لیے رابطہ کریں
ڈیٹا شیٹ دیکھیں →MAX485EESA+
✅ ڈراپ-اِن ⚠️ تفصیلات غیر تصدیق شدہقیمت کے لیے رابطہ کریں
ڈیٹا شیٹ دیکھیں →SN75176BDR
✅ ڈراپ-اِنقیمت کے لیے رابطہ کریں
ڈیٹا شیٹ دیکھیں →SP485EN-L/TR
✅ ڈراپ-اِن📋 حوالہ جاتی متبادل (کیٹلاگ میں نہیں)
ST485ECDR
✅ ڈراپ-اِن📋 حوالہ جاتی متبادل (کیٹلاگ میں نہیں)
ISL8485ECBZ
✅ ڈراپ-اِن📋 حوالہ جاتی متبادل (کیٹلاگ میں نہیں)
MAX485ESA+ تفصیلات
| فنکشن | Transceiver |
| Protocol | RS-422, RS-485 |
| Number of Drivers/Receivers | 1/1 |
| Duplex | Half |
| سپلائی وولٹیج | 4.75 V to 5.25 V (5 V nominal) |
| ڈیٹا ریٹ | 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) |
| آپریٹنگ درجہ حرارت | -40 °C to +85 °C |
| پیکیج | 8-SOIC (SOIC-8) |
| ماؤنٹنگ ٹائپ | Surface Mount |
| RoHS اسٹیٹس | Compliant (per Maxim/ADI datasheet suffix '+') |
MAX485ESA+ پن کنفیگریشن
| پن 1 | RO — Receiver output (push-pull TTL/CMOS) |
| پن 2 | RE — Receiver output enable (active-low; tie low to enable RO) |
| پن 3 | DE — Driver output enable (active-high; tie high to drive DI onto A/B) |
| پن 4 | DI — Driver input (TTL/CMOS) |
| پن 5 | GND — Ground |
| پن 6 | A — Non-inverting differential driver output / receiver input |
| پن 7 | B — Inverting differential driver output / receiver input |
| پن 8 | VCC — +5 V supply |
عام استعمالات
MAX485ESA+ کے لیے موزوں ہے 7 ایپلیکیشنs: 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.
تجویز کردہ
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.
تجویز کردہ
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.
تجویز کردہ
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.
تجویز کردہ
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.
تجویز کردہ
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.
تجویز کردہ
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.
تجویز کردہ
تجویز کردہ پروڈکٹس کا خلاصہ
کے لیے انجینئرنگ ریفرنس ڈیٹا MAX485ESA+ — موازنہ، ڈیزائن رہنمائی، اور تعمیل کی معلومات۔
انتخاب کی گائیڈ
متبادلات کے ساتھ موازنہ
| پیرامیٹر | یہ پروڈکٹ | 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 |
اہم امتیازی خصوصیات
- Highest available node count on a single bus (بمقابلہSN75176BDR)
- Industry-standard pinout with broadest cross-brand second-sourcing (بمقابلہSP485EN-L/TR)
- Long-term availability through active Maxim/ADI catalog (بمقابلہISL8485ECBZ)
ڈیزائن نوٹس
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.
تعمیل کی معلومات
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.
