MAX485CUA+ - 5V RS-485/RS-422 Transceiver, 2.5Mbps | ADI/Maxim
N.º de pieza: MAX485CUA+ ✓ Activo| Cant. | Precio unitario | Total |
|---|---|---|
| 1 | $4.9079 | $4,91 |
| 10 | $4.41 | $44,10 |
| 100 | $3.74 | $374,00 |
| 500 | $3.18 | $1.590,00 |
| 1.000 | $2.71 | $2.710,00 |
MAX485CUA+ Descripción general
An RS-485/RS-422 transceiver is a bus-interface IC that converts between single-ended UART/CMOS logic on the controller side and the differential voltage signaling required for robust long-distance, multi-drop communication over twisted-pair cable. Transceivers such as the MAX485CUA+ sit inside the broader Interface IC family and provide the physical-layer (PHY) bridge for industrial fieldbus networks including Modbus, Profibus DP, DMX512, and BACnet, where common-mode noise immunity and cable lengths up to 1200 m are required.
Key features of the MAX485CUA+ include 2.5Mbps maximum data rate, 1/8 unit-load (up to 256 transceivers on a bus), thermal-shutdown protection, short-circuit current limiting on the driver outputs, a low-current shutdown mode (on the MAX481/MAX483/MAX487 variants, not the MAX485 itself), true fail-safe receiver inputs that guarantee a logic-high output when the differential input is open or shorted, and an ESD rating of greater than 15 kV HBM on the bus pins per the MAX485 datasheet family.
Architecturally, the MAX485CUA+ uses a differential line driver with slew-rate-limited edges on slower speed grades and an un-limited edge rate here for maximum 2.5Mbps throughput, paired with a differential receiver with internal hysteresis for noise rejection. The wide 4.75V to 5.25V supply range is compatible with 5V TTL logic rails; a 3.3V variant (MAX3485) and isolated versions (MAX1480) exist in the same family for different system-level needs.
Typical applications include industrial multi-drop RS-485 networks, building-automation HVAC controllers, point-of-sale terminals, packet-based utility metering, and any embedded system that requires half-duplex differential communication over long cables in electrically noisy environments.
When designing with the MAX485CUA+, place a 100 ohm termination resistor at each end of the bus and use a low-ESR 100 nF decoupling capacitor as close to VCC as possible. Select 100 ohm twisted-pair cable (EIA-485 characteristic impedance) and avoid star topologies; daisy-chain is required to prevent reflections.
This page synthesizes distributor pricing, verified drop-in alternatives, and practical PCB/layout design notes derived from the MAX485 datasheet family and reference designs not reproduced on distributor product pages.
Alternativas directas para MAX485CUA+ — mismo encapsulado, compatible pin a pin. Se excluyen las piezas de otro encapsulado que requieren retrabajo de la PCB.
Variantes de esta serie
Modelos de la misma serie compatibles directamente con MAX485CUA+ (mismo factor de forma y huella) — difiere en Data Rate, Number of Drivers/Receivers, Operating Temperature, Receiver Hysteresis, RoHS Status.
Herramienta de comparación rápida — seleccione piezas alternativas para compararlas lado a lado:
MAX485ESA+
✅ Sustitución directa✓ En stock
$0.92 / unidad
Ver hoja de datos →MAX485ESA+
✅ Sustitución directa✓ En stock
$0.92 / unidad
Ver hoja de datos →MAX485CSA
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
MAX485CSA+
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
MAX483ESA+
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
MAX485CUA+ Especificaciones
| Función | Transceiver |
| Number of Drivers/Receivers | 1 / 1 |
| Protocol | RS-422, RS-485 |
| Velocidad de datos | 2.5 Mbps (max) |
| Supply Voltage (VCC) | 4.75 V to 5.25 V |
| Supply Current (no load) | 300 uA (typical) |
| Temperatura de funcionamiento | 0 C to +70 C (C suffix) |
| Encapsulado / Carcasa | 8-uMAX / 8-uSOP |
| Tipo de montaje | Surface Mount |
| Receiver Hysteresis | 50 mV (typical) |
| ESD Protection (bus pins, HBM) | 15 kV |
| Number of Transceivers on Bus | 32 (1 unit load) |
| Duplex | Half |
| Estado RoHS | Compliant |
| Lead-Free / Halogen-Free | Yes / Yes |
Configuración de pines de MAX485CUA+
| Pin 1 | RO — Receiver Output (push-pull) |
| Pin 2 | RE — Receiver Output Enable, active-low |
| Pin 3 | DE — Driver Output Enable, active-high |
| Pin 4 | DI — Driver Input |
| Pin 5 | GND — Ground |
| Pin 6 | A — Non-inverting driver output / non-inverting receiver input |
| Pin 7 | B — Inverting driver output / inverting receiver input |
| Pin 8 | VCC — Supply input, 4.75V to 5.25V |
Aplicaciones típicas
MAX485CUA+ es adecuado para 6 aplicacións: Industrial RS-485 Multi-Drop Networks, Building-Automation HVAC Controllers, Point-of-Sale Terminals and Retail Networks, Utility Metering and Smart-Grid AMI, DMX512 Stage Lighting and Entertainment, Embedded UART-to-RS485 Bridge Module.
Industrial RS-485 Multi-Drop Networks
The MAX485CUA+ is a foundational building block for industrial multi-drop RS-485 networks, including Modbus RTU and Profibus DP sub-segments found in factory automation. Its 1/1 unit load allows up to 32 transceivers to share a single twisted pair while the 2.5 Mbps maximum data rate supports high-speed fieldbus traffic where required. The 15 kV HBM ESD on the bus pins, combined with thermal shutdown and short-circuit current limiting, lets the part survive the cable-side transients typical of motor-control cabinets. Placed on each PLC I/O card near the bus connector, it bridges the 5V UART to the differential pair and uses the standard 100 ohm termination at cable ends. Compared to a 3.3 V LVDS driver, the MAX485CUA+ trades quiescent current for far longer cable reach and stronger common-mode rejection.
Recomendado
Building-Automation HVAC Controllers
Building-automation systems use the MAX485CUA+ on BACnet MSTP and Modbus sub-networks that connect thermostats, VAV controllers, and AHU modules across long stretches of conduit. The 4.75V to 5.25V supply aligns with the 5V rails still common in HVAC boards, while the wide common-mode range of the RS-485 receiver handles ground-potential differences between floors. With 2.5 Mbps capability, the part can also serve faster DMX512 lighting retrofits in commercial spaces. Designers usually terminate the bus at each end with 100 ohm resistors and bias the A line above B with the typical 680 ohm pull-up / 680 ohm pull-down fail-safe network. The 0 C to +70 C commercial temperature grade is sufficient for indoor plenums.
Recomendado
Point-of-Sale Terminals and Retail Networks
Point-of-sale (POS) terminals, barcode scanners, and EFT-PIN pads rely on the MAX485CUA+ to communicate with back-office ECRs over RS-485 runs that may reach 100 m. Its compact 8-uMAX footprint fits beside the printer driver board, and the 2.5 Mbps data rate supports both transaction traffic and occasional firmware download. The fail-safe receiver prevents false framing when the cashier yanks a cable mid-shift, and the 15 kV ESD withstand protects the bus from operator-side static discharge. The part typically sits at one corner of the main PCB with a 100 nF decoupling cap and a 100 ohm termination at the chassis RJ-45. Compared with USB-based POS links, RS-485 over the MAX485CUA+ offers longer cable runs and simpler multi-drop cash-drawer architectures.
Recomendado
Utility Metering and Smart-Grid AMI
Advanced Metering Infrastructure (AMI) uses the MAX485CUA+ for last-mile concentrator-to-meter RS-485 spur lines operating over 12 AWG twisted-pair cable on utility poles. Each meter enclosure pulls 5 V from the meter's auxiliary supply and shares the bus with up to 32 neighbors, so the 1/1 unit load and 0 C to +70 C grade cover the common outdoor enclosure range. At 110 kbps the part easily reaches the 1200 m RS-485 maximum distance, allowing utilities to bridge multiple buildings without repeaters. The fail-safe receiver eliminates the need for end-of-line biasing in the often-ungrounded meter cans. Inside the meter's processing board it sits between a Cortex MCU's UART and the bus connector, often behind a TVS diode array for surge protection.
Recomendado
DMX512 Stage Lighting and Entertainment
Stage and architectural DMX512 lighting systems use the MAX485CUA+ to carry 250 kbps differential dimmer data over XLR cable runs that can exceed 100 m between fixtures. The 2.5 Mbps capability vastly exceeds the 250 kbps DMX512 requirement, leaving timing margin for splitter/repeater chains. With 32 unit loads available, a single DMX universe can host dozens of daisy-chained fixtures without exceeding the receiver budget. The 4.75 V to 5.25 V supply suits the 5 V rails found in lighting fixture main boards, and the 8-uMAX footprint is small enough to fit inside the fixture base. Compared to a dedicated DMX receiver IC, the MAX485CUA+ provides general-purpose reusability across the lighting rig.
Recomendado
Embedded UART-to-RS485 Bridge Module
Embedded developers commonly drop the MAX485CUA+ onto a small SOT-23-to-DIP bridge module that converts a 3.3 V or 5 V MCU UART into an RS-485 bus for prototyping and field retrofit. The 8-uMAX low profile is friendly to breadboard-friendly module designs, and the 2.5 Mbps capability lets the same module support both slow fieldbus and faster custom protocols. Its 4.75V to 5.25V supply is taken from a 5V LDO, and the 100 nF decoupling capacitor goes on the same side of the PCB as the IC. The fail-safe receiver and 15 kV ESD simplify PCB layout when the module is hand-wired. Compared to an MCU-internal RS-485 peripheral, the MAX485CUA+ offers galvanic robustness and bus-isolation options when paired with an external isolator.
Recomendado
Resumen de productos recomendados
Datos de referencia de ingeniería para MAX485CUA+ — comparación, orientación de diseño e información de cumplimiento.
Guía de selección
Comparación con alternativas
| Parámetro | Este producto | MAX485ESA | MAX485ESA+ | MAX485CSA | MAX485CSA+ | MAX483ESA+ |
|---|---|---|---|---|---|---|
| Package | 8-uMAX / 8-uSOP | 8-SOIC (pin-compatible) | 8-SOIC (pin-compatible) | 8-SOIC (pin-compatible) | 8-SOIC (pin-compatible) | 8-SOIC (pin-compatible) |
| Brand | Analog Devices (formerly Maxim Integrated) | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Data Rate (max) | 2.5 Mbps | 2.5 Mbps | 2.5 Mbps | 2.5 Mbps | 2.5 Mbps | 250 kbps (slew-rate limited) |
| Supply Voltage | 4.75 V to 5.25 V | 4.75 V to 5.25 V | 4.75 V to 5.25 V | 4.75 V to 5.25 V | 4.75 V to 5.25 V | 4.75 V to 5.25 V |
| Operating Temperature | 0 C to +70 C (C grade) | -40 C to +85 C (E grade) | -40 C to +85 C (E grade), Pb-free | 0 C to +70 C (C grade) | 0 C to +70 C (C grade), Pb-free | -40 C to +85 C (E grade), Pb-free |
| Lead-Free / RoHS | Yes / Yes | No / Yes (legacy finish) | Yes / Yes | No / Yes (legacy finish) | Yes / Yes | Yes / Yes |
| ESD (bus pins, HBM) | 15 kV | 15 kV | 15 kV | 15 kV | 15 kV | 15 kV |
| Slew-Rate Limited | No | No | No | No | No | Yes (250 kbps) |
| Typ. Price (1k qty) | $2.71 | $2.80 - $3.20 (industrial grade) | $2.90 - $3.30 | $2.50 - $2.90 (commercial SOIC) | $2.60 - $3.00 | $2.40 - $2.80 (lower speed) |
Diferenciadores clave
- Industry-standard MAX485 die with full 2.5 Mbps (not slew-rate limited) (frente a MAX483ESA+)
- Compact 8-uMAX / uSOP package vs SOIC-8 in family (frente a MAX485ESA+ (8-SOIC))
- Commercial 0C to +70C grade at lowest cost (frente a MAX485ESA+ (-40C to +85C))
Notas de diseño
Place a 100 nF low-ESR decoupling capacitor as close as possible to the VCC pin (pin 8) and to the GND pin (pin 5) using a wide, short trace. Keep the A and B differential traces matched in length and symmetrically routed with a ground reference plane underneath; this minimizes common-mode noise pickup and keeps the 2.5 Mbps eye diagram clean. Route DI, DE, RE, and RO on the digital side well away from the A/B bus side to avoid coupling digital switching noise into the cable.
Never leave RE floating - tie it to GND if the receiver is always enabled, or drive it from the MCU to select read/write states. Leaving RE floating can cause the receiver output to oscillate in noisy environments. Similarly, do not drive DE high while the part is unpowered, because the device's VCC-absent bus pins can back-power the supply rail through internal ESD diodes. Always terminate both ends of the bus with 100 ohm resistors matching the twisted-pair characteristic impedance per EIA-485; failing to terminate produces reflections that close the eye at 2.5 Mbps.
Estimated: at 5V supply, 2.5 Mbps continuous output into a properly terminated 100 ohm differential bus, the average driver dissipation is roughly 80 mW per channel (based on VOD-VCM differential current times VCC). The 8-uMAX package has theta_JA near 170 C/W on a standard 2-layer JEDEC board, so the junction rises only 13-14 C above ambient - no heatsink is required. However, in a fault condition (bus short to VCC or GND) the driver current limit fires and the package can dissipate up to 800 mW; rely on the part's internal thermal shutdown above +160 C junction for protection.
For cable lengths above 50 m at 2.5 Mbps, place the 100 ohm termination at both physical ends of the bus only; do not also place a termination at every node (multi-drop stubs). For very long runs with high baud rates, AC-couple the bus with a center-tap termination network (60 ohm in series with 1 nF across the line) to suppress DC common-mode bias. Keep stub lengths from the backbone to each transceiver below one-tenth of the signal rise time in propagation; for 2.5 Mbps with 8 ns edges, stubs should stay below roughly 20 cm on standard cable.
Información de cumplimiento
RoHS compliant per ADI/Maxim Integrated product page and the + suffix designation. Not AEC-Q100 qualified; for automotive applications, use the AEC-Q100 qualified MAX485ESA+ variant or the ADM485 from the ADI automotive line.
