MAX487ESA+ - Low-Power Slew-Rate-Limited RS-485/RS-422 Transceiver | Analog Devices
MPN： MAX487ESA+ ✓ 啟用中MAX487ESA+ 概覽
An RS-485 transceiver is a differential line driver/receiver that translates logic-level UART signals to a robust differential signal capable of being transmitted over long cables in electrically noisy environments. RS-485 supports multi-drop configurations of up to 32 transceivers on a single twisted pair, enabling half-duplex or full-duplex communication over distances up to 1200 m. RS-485 transceivers belong to the broader interface IC category within power management and communication ICs, and are standardized under TIA-485 (formerly EIA-485).
Key features include slew-rate-limited driver outputs that reduce EMI and reflections on unterminated or improperly terminated cables, true fail-safe receiver inputs that guarantee a known output state when the bus is idle or shorted, and a low-current shutdown mode that places the device in <0.1 µA quiescent for power-saving operation. The MAX487ESA+ carries ±15 kV HBM ESD protection on the bus pins, providing robust tolerance to electrostatic discharge events during handling and field installation.
The MAX487ESA+ integrates a complete half-duplex RS-485 link layer with internal cable termination management through slew-rate control rather than discrete termination. Its 5V single-supply operation simplifies power architecture in industrial 24V-rail-derived systems, and its robust differential signaling supports industrial control, building automation, and point-of-sale applications.
Typical applications include industrial fieldbus networks (Modbus, Profibus), HVAC building automation systems, motor control encoder feedback, point-of-sale (POS) terminals, security system intercom panels, and remote utility metering. The MAX487ESA+ pinout and protocol match the broader MAX481/MAX483/MAX485/MAX487/MAX1487 family, allowing drop-in upgrades and obsolescence mitigation across existing designs.
Design considerations: include a 100 nF decoupling capacitor close to VCC, place a 120 Ω termination resistor across the differential pair only at the cable ends, and ensure the cable shield is grounded at one end only to suppress ground loops. The DE and RE pins control driver/receiver direction; when using half-duplex, tie DE and /RE together with a single GPIO line.
This page synthesizes distributor inventory, parametrically matched drop-in alternatives from the MAX48x family and competitive second sources, and practical design notes that go beyond what the manufacturer datasheet alone provides.
直接替換替代品，適用於 MAX487ESA+ — 相同封裝，腳位對腳位相容。需重新設計 PCB 的不同封裝零件不列入。
此系列的變體
與下列產品可直接替換的同系列型號： MAX487ESA+ （相同外形與佔位） — 差異在於 Package, Data Rate, RoHS Status, Supply Voltage.
MAX487ESA+T
✅ 直接替換📋 參考替代品（不在目錄中）
MAX485ESA+
✅ 直接替換聯絡詢價
查看資料表 →MAX481ESA+
✅ 直接替換📋 參考替代品（不在目錄中）
MAX487CSA+
✅ 直接替換📋 參考替代品（不在目錄中）
MAX487EESA+
✅ 直接替換📋 參考替代品（不在目錄中）
SN65HVD72DR
✅ 直接替換📋 參考替代品（不在目錄中）
ST3485EIDT
✅ 直接替換📋 參考替代品（不在目錄中）
ISL8487EIBZ
✅ 直接替換📋 參考替代品（不在目錄中）
MAX487ESA+ 規格
| 功能 | Transceiver |
| Protocol | RS-422, RS-485 |
| Number of Drivers/Receivers | 1/1 |
| Duplex | Half |
| 供應電壓 | 4.75 V to 5.25 V |
| 資料速率 | 250 kbps |
| Supply Current (unloaded/loaded) | 120 µA to 500 µA |
| Shutdown Supply Current | 0.1 µA (typical) |
| ESD Protection (HBM, bus pins) | ±15 kV |
| Slew-Rate Limited | Yes |
| 工作溫度 | -40 °C to +85 °C |
| 封裝 | 8-SOIC (NS) |
| 安裝類型 | Surface Mount |
| 腳位數 | 8 |
| Lead-Free / RoHS | Lead-free, RoHS compliant |
MAX487ESA+ 腳位配置
| 腳位 1 | RO — Receiver Output (logic-level, push-pull) |
| 腳位 2 | /RE — Receiver Enable (active low; logic low enables RO) |
| 腳位 3 | DE — Driver Enable (logic high enables differential driver output) |
| 腳位 4 | DI — Driver Input (TTL/CMOS logic input) |
| 腳位 5 | GND — Ground |
| 腳位 6 | A — Driver Output / Receiver Input, non-inverting (Y on full-duplex) |
| 腳位 7 | B — Driver Output / Receiver Input, inverting (Z on full-duplex) |
| 腳位 8 | VCC — 5V Supply (4.75V to 5.25V) |
典型應用
MAX487ESA+ 適用於 6 應用s: Industrial Fieldbus Networks, Building Automation and HVAC, Point-of-Sale (POS) Terminals, Motor Control and Encoder Feedback, Security and Intercom Systems, Remote Utility Metering.
Industrial Fieldbus Networks
The MAX487ESA+ is widely deployed in industrial fieldbus networks running Modbus RTU, DMX512, or proprietary half-duplex protocols over a single shielded twisted pair. Its 250 kbps slew-rate-limited driver eliminates the need for discrete termination while reducing EMI on long cable runs, which is critical for industrial installations up to 1200 m. Place 120 Ω termination only at the cable ends and tie DE and /RE to a single GPIO line for direction control.
推薦
Building Automation and HVAC
Building automation controllers use the MAX487ESA+ on RS-485 links between HVAC thermostats, VAV box actuators, and centralized building management systems. The 120 µA unloaded supply current keeps power budget low for ceiling-mounted controllers, and the small SOIC-8 footprint suits compact PCB assemblies. With ±15 kV HBM ESD tolerance on the bus pins in the related E-variant, the part tolerates handling during installation.
推薦
Point-of-Sale (POS) Terminals
POS terminal daisy chains use the MAX487ESA+ to interconnect cash drawer controllers, receipt printers, and customer displays over a single RS-485 link inside retail enclosures. The 0.1 µA shutdown mode reduces idle power during POS sleep states, extending battery life on mobile terminals. The half-duplex topology minimizes cable count inside congested retail enclosures where space is at a premium.
推薦
Motor Control and Encoder Feedback
Servo drives and stepper motor controllers use the MAX487ESA+ to read encoder position feedback from distributed motor nodes. The 250 kbps data rate accommodates typical quadrature encoder streams at high RPM, while slew-rate-limited outputs reduce conducted emissions that could disturb adjacent analog feedback channels. The industrial -40 °C to +85 °C temperature rating ensures reliable operation inside sealed motor housings.
推薦
Security and Intercom Systems
Multi-building intercom and access-control panels use the MAX487ESA+ to bridge card readers, door controllers, and central access servers over RS-485. Fail-safe receiver inputs guarantee a defined logic output during cable faults, preventing doors from locking or unlocking spuriously. The 5V single-supply operation simplifies power tree design in PoE-powered intercom stations.
推薦
Remote Utility Metering
Utility metering networks use the MAX487ESA+ to daisy chain electricity, water, and gas meters back to a concentrator over several hundred meters of outdoor cable. Low quiescent current extends battery life in meter endpoints, and the -40 °C to +85 °C industrial temperature grade handles unheated outdoor enclosures. Multi-drop support accommodates dozens of meters on one shared bus.
推薦
推薦產品摘要
工程參考資料，適用於 MAX487ESA+ — 比較、設計指引及合規資訊。
選型指南
與替代品比較
| 參數 | 本產品 | MAX487ESA+T | MAX485ESA+ | MAX487EESA+ | SN65HVD72DR | ST3485EIDT |
|---|---|---|---|---|---|---|
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Texas Instruments | STMicroelectronics |
| Package | SOIC-8 | SOIC-8 | SOIC-8 | SOIC-8 | SOIC-8 | SOIC-8 |
| Supply Voltage | 4.75V to 5.25V | 4.75V to 5.25V | 4.75V to 5.25V | 4.75V to 5.25V | 3.0V to 3.6V | 3.0V to 3.6V |
| Data Rate | 250 kbps | 250 kbps | 2.5 Mbps | 250 kbps | 250 kbps | 12 Mbps |
| Slew-Rate Limited | Yes | Yes | No | Yes | Yes | Yes |
| Operating Temperature | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C |
| Shutdown Current | 0.1 uA | 0.1 uA | N/A (no shutdown) | 0.1 uA | 1 uA | 1 uA |
主要差異化特點
- Slew-rate-limited driver reduces EMI on unterminated cables (對比MAX485ESA+)
- Integrated 0.1 µA shutdown mode cuts idle power by 1000x (對比MAX485ESA+)
- Same SOIC-8 pinout as MAX485ESA+ for drop-in fieldbus upgrades (對比MAX485ESA+)
- Single 5V supply eliminates dual-rail complexity (對比MAX13487EESA+T)
設計說明
Place a 100 nF X7R ceramic decoupling capacitor within 5 mm of the VCC pin (pin 8) and another between GND (pin 5) and the ground plane. For multi-transceiver nodes, add a bulk 10 µF tantalum or ceramic cap on the same 5V rail. Keep the differential pair (A/B) routed as a 100 Ω differential transmission line over a continuous ground plane; this minimizes reflections and EMI.
Do not place 120 Ω termination resistors at every node. RS-485 termination should ONLY be placed at the two cable ends to avoid loading the bus. Leaving middle nodes unterminated lets reflections die out at the ends without overshoot. For multi-drop networks with stubs, keep stubs shorter than 1/10 of the signal rise time for clean signaling.
Although the MAX487 supports a 0.1 µA shutdown mode, designers often forget that DE must be logic low to achieve true shutdown current. If DE floats or sits high, the device draws 100s of µA continuously. Use a 100 kΩ pull-down on DE when shutdown mode is desired but the host MCU GPIO is not driven.
The MAX487ESA+ provides slew-rate-limited driver outputs that reduce high-frequency content. Use this part when cables are unterminated, stub lengths are non-trivial, or when EMI compliance is a concern. If higher data rates (above 250 kbps) are needed, switch to the MAX485ESA+ which lacks slew-rate limiting but supports 2.5 Mbps.
合規資訊
Lead-free and RoHS compliant per '+' suffix per manufacturer datasheet. Conflict-minerals compliance per manufacturer declaration. Not AEC-Q100 qualified - use automotive-grade transceiver for vehicle networks.
