MAX3485ESA+T - 10Mbps RS-485/RS-422 Transceiver | Analog Devices
料号： MAX3485ESA+T ✓ 量产中MAX3485ESA+T 概述
An RS-485/RS-422 transceiver is an interface IC that converts logic-level digital signals into differential bus voltages and receives differential bus voltages back into CMOS-compatible logic signals. It belongs to the communication interface IC hierarchy: transceiver > RS-485/RS-422 interface > differential line driver and receiver > semiconductor. The MAX3485 combines both directions of signal conversion in one package while sharing a conductor pair during half-duplex operation.
Key features include a 3.3V power supply, one driver and one receiver, a 10Mbps maximum data rate, and operation as a true half-duplex RS-485/RS-422 interface. Its driver supports short-circuit protection, and the integrated receiver provides the differential input thresholding required by RS-485 and RS-422 systems. The 8-SOIC package also allows reuse of existing SOIC-8 PCB layouts when a board revision changes the transceiver source.
The MAX3485 family is designed for low-power communications equipment where each node must both transmit and receive over a wired bus. A controlled driver slew rate reduces unwanted high-frequency energy on the cable, while the half-duplex architecture reduces the number of transceivers and interface signals needed at each node. Exact propagation-delay, receiver-threshold, supply-current, and ESD ratings were not included in the supplied source excerpts and must be confirmed in the manufacturer datasheet before release.
Typical uses include industrial data acquisition, building controls, instrumentation links, and embedded systems communicating with remote sensors over RS-485. It is also appropriate for point-to-point RS-422 links where the same transceiver pinout supports both directions. In a multi-drop RS-485 network, bias resistors and termination must be designed for the cable length, topology, and number of idle nodes to avoid excessive common-mode loading.
The principal design consideration is transceiver direction control. DE and /RE can be managed separately or tied together, but the firmware must avoid asserting the driver while another node is transmitting because multiple drivers can conflict on the shared bus. Keep the bus wiring away from noisy sources, use proper signal and return paths, and verify the termination strategy for the selected data rate.
This product record combines verified manufacturer and distributor information with practical replacement, application, and layout guidance. It distinguishes the exact 10Mbps MAX3485ESA+T ordering code from related MAX3485 variants, highlights the available SOIC-8 drop-in choices, and identifies specifications that still require confirmation from the official datasheet.
直接替换替代料： MAX3485ESA+T ——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： MAX3485ESA+T （相同外形与封装尺寸） ——差异在于 Package, Data Rate, Operating Temperature, Product Type, Protocol.
MAX3485CSA+T
✅ 直接替换 ⚠️ 规格未核验联系询价
查看数据手册 →MAX3485ECSA+T
✅ 直接替换📋 参考替代料（不在目录中）
MAX3483ESA+T
✅ 直接替换 ⚠️ 规格未核验联系询价
查看数据手册 →MAX3488ESA+T
✅ 直接替换 ⚠️ 规格未核验联系询价
查看数据手册 →SP3485CN-L
✅ 直接替换联系询价
查看数据手册 →MAX3485ESA+T 规格参数
| Product Type | RS-485/RS-422 transceiver |
| 电源电压 | 3.3 V |
| Maximum Data Rate | 10 Mbps |
| Driver Count | 1 |
| Receiver Count | 1 |
| Duplex Mode | Half-duplex |
| Supported Standards | RS-422 and RS-485 |
| 封装 | 8-SOIC |
| Package Dimensions | 3.90 mm width |
| 安装类型 | Surface mount |
| Ordering Package | Tape and reel |
MAX3485ESA+T 引脚配置
| 引脚 1 | RO — Receiver output |
| 引脚 2 | /RE — Active-low receiver enable |
| 引脚 3 | DE — Driver enable |
| 引脚 4 | DI — Driver input |
| 引脚 5 | GND — Ground |
| 引脚 6 | Y — Inverting driver output and receiver input |
| 引脚 7 | A — Non-inverting driver output and receiver input |
| 引脚 8 | VCC — Positive supply |
典型应用
MAX3485ESA+T 适用于 6 应用s: Industrial Sensor Networking, Building Automation, Point-to-Point RS-422 Links, Instrumentation and Data Acquisition, Embedded Communications, RS-485 to RS-232 Gateways.
Industrial Sensor Networking
The MAX3485ESA+T fits industrial sensor networks that distribute a 3.3V RS-485 bus among remote sensing nodes. Its one-driver, one-receiver arrangement supports bidirectional half-duplex communication over a shared differential pair, while the 10Mbps rate allows short links to use a compact and inexpensive transceiver. Place the device near the field-bus connector, route A and Y as a coupled pair, and implement software-controlled DE and /RE operation to prevent bus contention. The exact common-mode range and temperature rating must be checked against the industrial environment before deployment.
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Building Automation
The MAX3485ESA+T is appropriate for low-voltage building-control nodes that exchange commands and measurements over an RS-485 backbone. The 3.3V supply aligns with modern controller logic, and the 8-SOIC footprint simplifies assembly in compact DIN-rail or room-control electronics. Use a single transceiver for half-duplex communication and manage driver enable timing in firmware. Cable routing away from motor and relay wiring is important because industrial building systems can contain significant EMI, especially when field cables are long.
推荐
Point-to-Point RS-422 Links
The MAX3485ESA+T can serve as the endpoint of a dedicated RS-422 point-to-point link because it combines a differential driver and differential receiver in one 8-pin device. The 10Mbps capability is useful for short, controlled links between an embedded controller and a remote peripheral. Unlike a multidrop RS-485 network, a point-to-point RS-422 arrangement requires less biasing, but termination still depends on cable length and data rate. Verify driver and receiver enable timing so both ends do not drive the pair simultaneously.
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Instrumentation and Data Acquisition
The MAX3485ESA+T is suitable for laboratory and process-instrumentation links where a controller gathers measurements from remote modules. Its differential interface improves noise immunity relative to single-ended communication, while half-duplex operation limits wiring and allows bidirectional command traffic. The 8-SOIC package also helps keep the analog and digital sections of a compact instrument separated. For long cable runs, reduce the signaling rate or use a transceiver with a wider common-mode range, and confirm the exact MAX3485 timing and environmental specifications before installation.
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Embedded Communications
The MAX3485ESA+T is appropriate for embedded controllers that need a compact wired communications port without adding a larger bus transceiver package. A microcontroller can connect to the logic-side DI, RO, DE, and /RE signals while the 8-SOIC device handles the differential bus. The 3.3V operation and 10Mbps capability suit short local links, but firmware must enforce a turnaround delay that allows the driver to release before the receiver samples a response. Firmware-driven direction control also supports polling multiple remote nodes on one pair.
推荐
RS-485 to RS-232 Gateways
The MAX3485ESA+T can form the differential RS-485 side of a gateway that connects legacy RS-232 equipment to a modern industrial bus. Its one-driver and one-receiver architecture provides a compact half-duplex physical layer, while the controller handles protocol conversion and buffer management. Place the transceiver near the connector and preserve a controlled return path for the RS-232 side. Because mixed legacy networks can expose ports to ground-potential differences, an isolation barrier such as a digital isolator should be considered when the application requires galvanic protection.
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推荐产品汇总
工程参考数据： MAX3485ESA+T ——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 | MAX3485CSA+T | MAX3485ECSA+T | MAX3483ESA+T | MAX3488ESA+T | SP3485 |
|---|---|---|---|---|---|---|
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices | MaxLinear |
| Package | 8-SOIC | 8-SOIC | 8-SOIC | 8-SOIC | 8-SOIC | 8-SOIC |
| Supported Interface | RS-485 and RS-422 | RS-485 and RS-422 | RS-485 and RS-422 | RS-485 and RS-422 | RS-485 and RS-422 | RS-485 and RS-422 |
| Duplex Mode | Half-duplex | Half-duplex | Half-duplex | Half-duplex | Half-duplex | Half-duplex |
关键差异点
- Exact 10Mbps MAX3485 positioning （对比 MAX3485ECSA+T)
- Established manufacturer family （对比 SP3485)
- Same 8-SOIC footprint （对比 SP3485)
- Matched speed option （对比 MAX3485CSA+T)
设计说明
Place the MAX3485ESA+T close to the board connector so the exposed Y and A traces do not become long antennas. Route A and Y as a tightly coupled differential pair over a continuous reference plane, minimize stubs, and provide a clear return path. Keep switching regulators, relay contacts, and high-current motor wiring away from the bus connector. For an 8-SOIC footprint, preserve the manufacturer's recommended copper and thermal layout rather than adding an arbitrary exposed pad.
Place the local supply-decoupling capacitor immediately between VCC pin 8 and GND pin 5, with the shortest possible ground return. The MAX3485 is specified as a 3.3V-powered device, but the exact permitted supply range and current consumption were not present in the supplied excerpts and must be checked in the manufacturer datasheet. Design the supply to handle transceiver switching transients without allowing rail noise to move directly into the differential receiver.
Do not allow two nodes to drive the RS-485 bus simultaneously. Assert DE only while transmitting, deassert it before listening for a reply, and allow enough driver turn-off time before sampling RO. The same care applies to /RE, which should not be left in a state that prevents reception. Firmware timing must account for driver and receiver propagation delay because the supplied excerpts do not provide those numerical values.
Termination, biasing, and cable length must be treated as one signal-integrity system. Use termination appropriate for the topology and data rate, and avoid excessive fail-safe bias voltage across multiple idle receivers. Do not automatically install termination at every node in a multidrop bus. Confirm the receiver common-mode range, which is unavailable in the supplied data, before using long cables or electrically noisy industrial equipment.
合规信息
The supplied excerpts do not provide verified RoHS, REACH, AEC-Q100, lead-free, halogen-free, or conflict-minerals declarations for the exact MAX3485ESA+T ordering code. AEC-Q100 is treated as not applicable because the product is an industrial/communications interface IC rather than an automotive-qualified variant.
