In applications such as industrial control, building automation, motor drives, and data acquisition, the RS485 bus has long been the dominant choice due to its advantages of long-distance transmission, strong interference resistance, and support for multi-point communication. A stable, high-speed, and compatible transceiver chip is crucial for ensuring the quality of bus communication.

The XBLW XBLWSN75176B/SN65176B differential bus transceiver. This chip is specifically designed for multi-point data transmission and fully complies with the EIA standard RS485 protocol, and is also compatible with the RS422 protocol.

Key Features:

Wide common-mode range, strong interference immunity.

The SN75176B/SN65176B supports an extended common-mode voltage range from 7V to +12V. This significantly improves the reliability of the system in harsh industrial environments.

Single-chip, +5V power supply, high-speed transmission

The chip utilizes a single +5V power supply, offering high integration and ease of use. Its driver has a propagation delay of only 22ns, enabling it to meet the demands of high-speed data communication.

Multi-point communication capability

The combination of the driver's output impedance and the receiver's input impedance is less than that of a single RS485 unit, allowing a total of up to 32 transceivers to be connected on a single bus. This makes it suitable for complex node networks.

L. Comprehensive protection mechanisms

Thermal shutdown protection: When a bus voltage conflict or short circuit causes excessive current draw within the device, the thermal shutdown circuit forces the driver to output at a high impedance, effectively preventing damage to the device.

Fail-safe design: The receiver has a typical 70mV hysteresis, and when the input is open-circuited, the output presents a high impedance, which improves signal stability.

Low power consumption and flexible shutdown.

Regardless of whether the device is in its three-state mode or is powered off, the bus pin exhibits high impedance across the entire common-mode range. This allows unused devices to be completely disconnected, thereby reducing the overall system power consumption.

Model and Packaging Options

The XBLWSN75176B/SN65176B series is available in DIP8 and SOP8 packages to meet various design requirements.

Note: The primary difference between the SN65176B and the SN75176B is their operating temperature range. The SN65176B is designed for industrial applications (40°C to +105°C), while the SN75176B is suitable for commercial applications (0°C to +70°C). Engineers can choose the appropriate device based on the specific application environment.

Optimal parameters and recommended working conditions

To ensure the long-term stability of the device, it is essential to adhere to the following limits:

Recommended working conditions:

Power supply voltage (VCC): 4.75V to 5.25V

Bus voltage (common or differential): -7V to +12V

Operating temperature (TA):

SN75176B: 0°C to +70°C

SN65176B: Operates from 40°C to +105°C

Switch characteristics and timing

For high-speed communication, timing parameters are critical. Here are some key timings (CL=100pF, RLDIFF=60Ω):

Driver signal propagation delay (tPLH/tPHL): 12ns

Driver rise/fall time (Tr/Tf): 18ns

Receiver transmission delay (tPHL): 30ns

The receiver enables output (ZL/ZH): Fastest reach 11ns

Functional Logic Table

Transmission mode

Note: When a short circuit or bus contention fault is detected, the thermal shutdown protection will activate, with 'X' representing any state.

Receiving

Note: The receiver features a fail-safe design; when open, it outputs a high impedance, where 'X' represents any state.

Conclusion

The XBLWSN75176B/SN65176B is a highly suitable RS485 communication interface chip for industrial environments, smart instruments, and motor control applications. Its features include high speed, a wide common-mode range, strong drive capability, and comprehensive thermal protection. The industrial-grade version (SN65176B) is designed to operate reliably in an environment ranging from 40°C to +105°C, providing greater reliability for system design.