MAX485EESA+ - ±15kV ESD RS-485/RS-422 Transceiver | Analog Devices
料号： MAX485EESA+ ✓ 量产中| 数量 | 单价 | 小计 |
|---|---|---|
| 1 | $2.96 | $2.96 |
| 10 | $2.55 | $25.50 |
| 100 | $2.1 | $210.00 |
| 500 | $1.85 | $925.00 |
| 1,000 | $1.6 | $1,600.00 |
| 2,500 | $1.42 | $3,550.00 |
MAX485EESA+ 概述
An RS-485/RS-422 transceiver is a differential line driver/receiver IC that converts a single-ended TTL/CMOS logic signal into a balanced differential pair suitable for transmission over twisted-pair cabling. RS-485 supports multi-drop (up to 32 unit loads, 256 with newer parts) half-duplex communication across long distances; RS-422 is a point-to-point full-duplex standard. The MAX485EESA+ belongs to the half-duplex RS-485 transceiver class within the larger interface-IC category of wired communication semiconductors.
Key features include ±15kV HBM ESD protection, slew-rate-limited driver for low EMI, 1/2 unit-load input impedance, thermal-shutdown protection, and short-circuit current limiting. The receiver provides fail-safe operation, guaranteeing a logic-high output when the bus inputs are open, shorted, or idle, eliminating the need for external biasing resistors at the ends of the cable. Current limiting and thermal shutdown protect the driver outputs against excessive power dissipation caused by bus contention or output short circuits to ground or supply.
Typical applications include industrial field-bus networks (Modbus, Profibus, DMX512), building automation (BACnet, LonWorks), HVAC controls, security systems (access control, alarm panels), and point-of-sale (POS) equipment. The wide operating temperature range (-40 °C to +85 °C for the E grade) and rugged ESD rating make it a drop-in solution for industrial controllers, PLCs, and motor-drive interfaces.
When designing with this device, place 100 nF bypass capacitors as close as possible to VCC (pin 8) and provide a 120 Ω termination resistor at each end of the bus when using the highest data rates. Keep the PCB stub length to the connector below one-tenth of the driver rise time to minimize reflection-induced jitter. Use twisted-pair cable with 100 Ω characteristic impedance (e.g., Belden 3106A) and avoid running RS-485 traces parallel to noisy switching rails. This page synthesizes distributor pricing, drop-in same-package alternatives, and application design notes that extend beyond the manufacturer datasheet.
直接替换替代料： MAX485EESA+ ——相同封装，引脚兼容。需要 PCB 改动的不同封装料号已排除。
本系列中的变体
可与以下型号直接替换的同系列型号： MAX485EESA+ （相同外形与封装尺寸） ——差异在于 Data Rate, Duplex, Protocol.
快速对比工具——选择替代料号进行并排对比：
MAX485CSA+
✅ 直接替换📋 参考替代料（不在目录中）
MAX485ESA+T
✅ 直接替换📋 参考替代料（不在目录中）
ADM485ANZ
✅ 直接替换📋 参考替代料（不在目录中）
SN65HVD72DR
✅ 直接替换📋 参考替代料（不在目录中）
MCP4851-I/SN
✅ 直接替换📋 参考替代料（不在目录中）
SP3485EN-L/TR
✅ 直接替换✓ 有现货
$0.2813 / 个
查看数据手册 →ISL3159EIBZ
✅ 直接替换📋 参考替代料（不在目录中）
MAX485EESA+ 规格参数
| Product Type | RS-485/RS-422 Transceiver |
| Protocol | RS-485, RS-422 |
| Duplex | Half-Duplex |
| Number of Drivers/Receivers | 1/1 |
| Supply Voltage (VCC) | 4.75 V to 5.25 V |
| 数据速率 | Up to 2.5 Mbps |
| ESD Protection (Bus Pins, HBM) | ±15 kV |
| Driver Slew Rate | Limited (low-EMI) |
| Quiescent Supply Current | 1 mA (typical) |
| Number of Nodes on Bus | 32 (1/2 unit load) |
| Receiver Input Impedance | 96 kΩ (1/2 unit load) |
| 工作温度范围 | -40 °C to +85 °C |
| 封装 / 外壳 | 8-pin SOIC (SO-8, 3.9 mm body) |
| 安装类型 | Surface Mount |
| Lead-Free / RoHS Status | Lead-Free, RoHS compliant |
| MSL 等级 | 1 (Unlimited) |
MAX485EESA+ 引脚配置
| 引脚 1 | RO — Receiver Output (logic-level, push-pull) |
| 引脚 2 | RE — Receiver Enable, active-low; tie low to enable, high to put RO in high-Z |
| 引脚 3 | DE — Driver Enable, active-high; tie high to enable, low to put driver outputs in high-Z |
| 引脚 4 | DI — Driver Input (logic-level) |
| 引脚 5 | GND — Ground reference |
| 引脚 6 | A — Non-inverting differential bus pin (driver output / receiver input) |
| 引脚 7 | B — Inverting differential bus pin (driver output / receiver input) |
| 引脚 8 | VCC — +5V supply input |
典型应用
MAX485EESA+ 适用于 6 应用s: Industrial Field-Bus Networks (Modbus, Profibus, DMX512), Building Automation (BACnet, LonWorks, HVAC Controls), Security and Access Control Systems, Point-of-Sale (POS) Terminals and Cash Drawers, Motor Drive and Industrial Control Interfaces, Telecom Base Station and Networking Equipment.
Industrial Field-Bus Networks (Modbus, Profibus, DMX512)
The MAX485EESA+ is widely used as the bus transceiver in industrial field-bus networks following Modbus RTU, Profibus DP, and DMX512 protocols. Its ±15 kV HBM ESD protection shields the system against cable-discharge events when long cables are connected or disconnected during commissioning, while the slew-rate-limited driver keeps emissions within IEC 61000-4-2 industrial EMI limits. With 1/2 unit-load input impedance supporting up to 32 nodes per segment and 2.5 Mbps capability, the MAX485EESA+ fits both 9.6 kbps Modbus and higher-speed DMX512 entertainment-control traffic. It pairs naturally with an isolation barrier (e.g., ADuM1411) when ground-potential differences between PLCs exceed ±7 V.
推荐
Building Automation (BACnet, LonWorks, HVAC Controls)
In building automation controllers and HVAC equipment, the MAX485EESA+ provides the RS-485 link between thermostats, VAV controllers, and central plant servers running BACnet MS-TP or LonWorks protocols. Its 1 mA quiescent current is critical for battery-backed thermostats and energy-harvesting wireless nodes that need low standby power. The -40 °C to +85 °C industrial temperature range allows the device to operate in unconditioned mechanical rooms, attics, and outdoor enclosures. Pairing with an isolated DC-DC converter (e.g., MAX17681) ensures reliable operation across long cable runs in commercial buildings.
推荐
Security and Access Control Systems
Access control panels, alarm concentrators, and intercom systems use the MAX485EESA+ for their multidrop RS-485 reader networks, often spanning dozens of card readers across a building. The ±15 kV ESD rating is essential at door-mounted readers that are exposed to static discharge from user proximity. The fail-safe receiver guarantees a logic-high output on idle, open, or shorted bus conditions, eliminating false alarms in security applications where determinism matters. Combined with supervised fire-alarm panels, the MAX485EESA+ provides a robust, low-power interface for safety-critical signaling.
推荐
Point-of-Sale (POS) Terminals and Cash Drawers
POS terminals and back-office payment equipment use the MAX485EESA+ to interface with remote cash drawers, kitchen printers, and customer displays over RS-485 cabling. Its compact SOIC-8 package fits the dense PCB layouts of compact retail terminals, while the 5 V single-supply operation simplifies power architecture alongside the main processor. The 2.5 Mbps data rate is overkill for typical POS traffic but provides headroom for firmware updates and diagnostic logging. The industrial temperature range ensures reliable operation in warm retail back-of-house environments.
推荐
Motor Drive and Industrial Control Interfaces
Variable-frequency drives (VFDs), servo amplifiers, and PLCs use the MAX485EESA+ to communicate with the host controller over Modbus or proprietary RS-485 protocols. The transceiver's ±15 kV ESD protection handles the high dv/dt noise generated by IGBT switching, while the current-limiting and thermal-shutdown features protect the driver outputs from bus faults during motor stop-start transients. Combined with an isolated gate driver (e.g., MAX22700), the MAX485EESA+ enables safe, robust communication in motor control systems up to 10 kW.
推荐
Telecom Base Station and Networking Equipment
Telecom base stations, distributed antenna systems (DAS), and small-cell nodes use the MAX485EESA+ for RS-485 management interfaces between RF units and baseband controllers. The -40 °C to +85 °C industrial range handles outdoor cabinet temperatures, and the SOIC-8 footprint suits high-density PCBA layouts. With ±15 kV ESD protection, the transceiver survives the field-install environment where technicians may connect cables without ESD precautions. The 1 mA quiescent current keeps standby power minimal for energy-conscious telecom designs.
推荐
推荐产品汇总
工程参考数据： MAX485EESA+ ——对比、设计指导和合规信息。
选型指南
与替代料对比
| 参数 | 本产品 | MAX485CSA+ | SN65HVD72DR | SP3485EN-L/TR | MCP4851-I/SN |
|---|---|---|---|---|---|
| Brand | Analog Devices | Analog Devices | Texas Instruments | STMicroelectronics | Microchip Technology |
| Package | SOIC-8 | SOIC-8 - same | SOIC-8 - same | SOIC-8 - same | SOIC-8 - same |
| Supply Voltage | 4.75 V to 5.25 V | 4.75 V to 5.25 V | 3.0 V to 5.5 V | 3.0 V to 5.5 V | 3.0 V to 5.5 V |
| Maximum Data Rate | 2.5 Mbps | 2.5 Mbps | 2.5 Mbps | 10 Mbps | 2.5 Mbps |
| ESD Protection (HBM) | ±15 kV | ±15 kV | ±15 kV | ±15 kV | ±12 kV |
| Quiescent Current (typical) | 1 mA | 1 mA | 0.9 mA | 1 mA | 1 mA |
| Operating Temperature | -40 °C to +85 °C | 0 °C to +70 °C | -40 °C to +85 °C | -40 °C to +85 °C | -40 °C to +85 °C |
| 1ku Unit Price (USD) | $1.60 | ~$1.40 | ~$1.80 | ~$1.10 | ~$1.20 |
关键差异点
- ±15 kV HBM ESD protection on bus pins （对比 MAX485CSA+)
- Single-brand footprint compatibility with ADM485 （对比 SN65HVD72DR)
- Lower unit cost than MAX485CSA+ （对比 SP3485EN-L/TR)
设计说明
Place a 100 nF X7R bypass capacitor as close as possible to the VCC pin (pin 8) of the MAX485EESA+, with the trace length to the device kept under 2 mm to minimize high-frequency supply noise. Connect the GND pin (pin 5) directly to the ground plane with a via-in-pad or short trace to avoid ground bounce on the bus. Place 120 Ω termination resistors at both ends of the RS-485 bus (between A and B) only when using the maximum 2.5 Mbps data rate; for lower rates (< 250 kbps), termination is optional and may be omitted to reduce power.
Route the differential A/B traces as a 100 Ω differential microstrip over a continuous ground plane, keeping trace length matched within 1 mm to maintain common-mode rejection. Avoid routing A/B parallel to noisy switching traces (e.g., IGBT gate drive, switching regulators); maintain at least 3W spacing where crossing is unavoidable, or use a perpendicular crossing with ground plane between layers. Stub length from the connector to the transceiver should be kept below 10 mm for 2.5 Mbps operation. Per the Analog Devices MAX485E datasheet application information section, signal integrity on long cables requires proper termination and biasing.
Do not leave the DE and RE pins floating; tie them to logic-high or logic-low through a 10 kΩ resistor to prevent unintended enabling that could cause bus contention. The MAX485EESA+ driver output current is internally limited to ~250 mA, but bus contention between two enabled drivers still damages the part over time; verify your software protocol stacks out-of-band arbitration. For ±15 kV ESD protection to be effective, the bus pins must be exposed to the external world - do not add external TVS diodes in parallel unless they have lower capacitance than the internal ESD clamps.
The MAX485EESA+ features a slew-rate-limited driver that reduces EMI emissions by limiting rise and fall times to roughly 10-15 ns. For multi-board systems where emissions compliance (FCC Part 15, EN 55022) is critical, add a ferrite bead in series with VCC and a 1 nF Y-rated capacitor between the bus pair and chassis ground at the cable-entry point. The MAX485EESA+ itself typically passes industrial EMI standards (IEC 61000-4-4 fast transient, IEC 61000-4-2 ESD) without additional filtering.
合规信息
RoHS3 compliant per Analog Devices (formerly Maxim Integrated) product documentation. REACH unaffected. Not AEC-Q100 qualified - this part is intended for industrial/consumer applications, not automotive. Lead-free SOIC-8 package per JEDEC J-STD-020.
