Overview
The SN65HVD21DR, produced by Texas Instruments, is a member of the SN65HVD2x family of extended common-mode RS-485 transceivers. These devices are designed to offer superior performance compared to typical RS-485 transceivers, exceeding the requirements of the TIA/EIA-485-A standard. They are optimized for bidirectional data transmission on multipoint twisted-pair cables, making them suitable for harsh environments and long-cable networks.
The SN65HVD21DR combines a 3-state differential driver and a differential receiver, both operating from a single 5-V power supply. This configuration minimizes loading on the bus, ensuring reliable operation over extended cable lengths.
Key Specifications
| Parameter | Value | Unit |
|---|---|---|
| Common-mode voltage range | –20 V to 25 V | V |
| Operating temperature range | –40°C to 85°C | °C |
| Supply voltage | 4.5 V to 5.5 V | V |
| Maximum data rate | Up to 5 Mbps | Mbps |
| Number of connected nodes | Up to 256 nodes | |
| ESD protection | Over 16-kV HBM | |
| Standby supply current | 1 µA (maximum) | µA |
| Receiver hysteresis | More than 100 mV | mV |
| Package type | SOIC (8 pins) |
Key Features
- Extended common-mode voltage range (–20 V to 25 V), more than doubling the TIA/EIA-485 requirement.
- High ESD protection to over 16-kV HBM.
- Failsafe receiver for open-circuit, short-circuit, and idle-bus conditions.
- Low standby supply current of 1 µA (maximum).
- More than 100 mV receiver hysteresis.
- Reduced unit-load for up to 256 nodes.
- Controlled driver output slew rate for reliable switching and reduced high-frequency noise emissions.
Applications
- Digital motor controllers.
- Remote sensors and terminals.
- Industrial process control.
- Security stations.
- Environmental control systems.
- Long cable solutions in factory automation, security networks, and building HVAC systems.
- Severe electrical environments such as electrical power inverters, industrial drives, and avionics.
Q & A
- What is the common-mode voltage range of the SN65HVD21DR?
The common-mode voltage range is –20 V to 25 V, which more than doubles the TIA/EIA-485 requirement.
- What is the maximum data rate supported by the SN65HVD21DR?
The SN65HVD21DR supports data rates up to 5 Mbps.
- How many nodes can be connected using the SN65HVD21DR?
Up to 256 nodes can be connected at moderate data rates.
- What level of ESD protection does the SN65HVD21DR offer?
The SN65HVD21DR offers ESD protection to over 16-kV HBM.
- What is the standby supply current of the SN65HVD21DR?
The standby supply current is 1 µA (maximum).
- What is the receiver hysteresis of the SN65HVD21DR?
The receiver hysteresis is more than 100 mV.
- What types of applications are the SN65HVD21DR devices suitable for?
They are suitable for digital motor controllers, remote sensors and terminals, industrial process control, security stations, environmental control systems, and other applications requiring long cable solutions and operation in harsh electrical environments.
- What is the operating temperature range of the SN65HVD21DR?
The operating temperature range is –40°C to 85°C.
- What is the package type of the SN65HVD21DR?
The SN65HVD21DR is available in an SOIC (8 pins) package.
- Does the SN65HVD21DR have failsafe operation?
Yes, the SN65HVD21DR includes a failsafe receiver for open-circuit, short-circuit, and idle-bus conditions.
