Specifications
| Attribute | Value |
| Package | Tube,Tube |
| ProductStatus | Obsolete |
| Type | Transceiver |
| Protocol | RS422, RS485 |
| NumberofDrivers/Receivers | 1/1 |
| Duplex | Full |
| ReceiverHysteresis | 70 mV |
| DataRate | 2.5Mbps |
| Voltage-Supply | 4.75V ~ 5.25V |
| OperatingTemperature | -40°C ~ 85°C |
| MountingType | Surface Mount |
| Package/Case | 14-SOIC (0.154, 3.90mm Width) |
Overview
Description
MAX491EESD is Maxim’s half‑duplex RS‑485/RS‑422 transceiver (driver + receiver) for multi‑drop serial networks. It provides a differential DI/RO interface with a tri‑state DE/RE control, allowing easy node isolation on a shared bus. The device operates from a single supply, offers low power consumption, and includes a failsafe receiver that output stays high when inputs are open, shorted, or idle.
The EESD suffix denotes enhanced electrostatic discharge protection on the A and B bus pins (and related I/O), improving robustness in harsh environments such as industrial, automotive, or portable equipment.
Common uses include industrial automation, building automation, instrumentation and sensor networks, PLC interfaces, and other RS‑485/RS‑422 network implementations where rugged, ESD‑protected transceivers are beneficial.
The EESD suffix denotes enhanced electrostatic discharge protection on the A and B bus pins (and related I/O), improving robustness in harsh environments such as industrial, automotive, or portable equipment.
Common uses include industrial automation, building automation, instrumentation and sensor networks, PLC interfaces, and other RS‑485/RS‑422 network implementations where rugged, ESD‑protected transceivers are beneficial.
Equivalent
MAX491EESD is a 5V RS-485/RS-422 transceiver (half‑duplex) with ESD protection. Equivalents from other vendors include: TI SN65HVD178A; ST SP3485; Analog Devices ADM485. Any 5V RS-485/RS-422 transceiver with similar features can substitute—just verify pinout, baud rate, and drive strength.
Features
Here are the typical features of the MAX491EESD RS-485/RS-422 transceiver:
- Half‑duplex RS‑485/RS‑422 transceiver
- Single‑supply operation (2.7V–5.5V)
- Low quiescent and transmit power for power‑sensitive apps
- Fail‑safe receiver (guaranteed logic HIGH output when inputs are open, shorted, or idle)
- 1/8‑unit‑load on the bus (fewer constraints on bus topology)
- Wide bus‑pin common‑mode range; tolerant to fault conditions
- Robust ESD protection on A/B lines (EESD suffix)
- Bus fault and short‑circuit protection
- High‑speed operation (suitable for common RS‑485 data rates)
- 8‑pin package options (SOIC/DIP variants)
- Industrial/extended temperature options (depending on package)
Note: exact electrical specs (data rate, current, input thresholds, and protection levels) are in the datasheet.
- Half‑duplex RS‑485/RS‑422 transceiver
- Single‑supply operation (2.7V–5.5V)
- Low quiescent and transmit power for power‑sensitive apps
- Fail‑safe receiver (guaranteed logic HIGH output when inputs are open, shorted, or idle)
- 1/8‑unit‑load on the bus (fewer constraints on bus topology)
- Wide bus‑pin common‑mode range; tolerant to fault conditions
- Robust ESD protection on A/B lines (EESD suffix)
- Bus fault and short‑circuit protection
- High‑speed operation (suitable for common RS‑485 data rates)
- 8‑pin package options (SOIC/DIP variants)
- Industrial/extended temperature options (depending on package)
Note: exact electrical specs (data rate, current, input thresholds, and protection levels) are in the datasheet.
Pinout
- Pin count: 8 pins (SOIC-8/TSSOP-8).
- Function: Single-channel, low-power RS-485/RS-422 transceiver (half-duplex) with driver and receiver. Pins include A/B (bus), DI (driver input), RO (receiver output), DE (driver enable), /RE (receiver enable, active low), VCC, and GND.
- Function: Single-channel, low-power RS-485/RS-422 transceiver (half-duplex) with driver and receiver. Pins include A/B (bus), DI (driver input), RO (receiver output), DE (driver enable), /RE (receiver enable, active low), VCC, and GND.
Manufacturer
Manufacturer: Maxim Integrated (now part of Analog Devices, Inc., ADI).
What kind of company: A global semiconductor company that designs and sells analog and mixed-signal integrated circuits (ICs), including transceivers, power management, sensors, and related devices.
What kind of company: A global semiconductor company that designs and sells analog and mixed-signal integrated circuits (ICs), including transceivers, power management, sensors, and related devices.
Application
MAX491EESD is a low-power RS-485/RS-422 transceiver with ESD protection. Typical application areas:
- Industrial automation and process control (PLCs, motor drives, sensors)
- Factory-floor multi-point RS-485 networks
- Building automation (HVAC, lighting, access control)
- Remote monitoring and telemetry (data acquisition, I/O)
- Point-to-point or multi-drop serial links in noisy environments
- Instrumentation and test equipment requiring robust serial communications
Note: Designed for rugged industrial conditions with ESD protection.
- Industrial automation and process control (PLCs, motor drives, sensors)
- Factory-floor multi-point RS-485 networks
- Building automation (HVAC, lighting, access control)
- Remote monitoring and telemetry (data acquisition, I/O)
- Point-to-point or multi-drop serial links in noisy environments
- Instrumentation and test equipment requiring robust serial communications
Note: Designed for rugged industrial conditions with ESD protection.
Package
8-pin SOIC (SO-8) package.
