5 THVD1424 and THVD1454 Flexible RS-485

All the problems described in the previous sections have one simple solution: THVD1424 and THVD1454.

Texas Instruments has released Industry’s first truly flexible RS-485 transceiver. This family has two unique devices:

• THVD1424 has on-chip 120-Ω switchable termination across driver and receiver bus pins, pin-controlled duplex switching and slew rate control to enable a common device for all types of networks and at all node locations. This device can be used in half-duplex or full-duplex RS-485 networks by configuring the pin H/F. The device has slew rate control pin SLR which can be used to set the device in maximum 20-Mbps mode or slew rate limited 500-kbps mode. Termination resistors are controlled using two pins TERM_TX and TERM_RX. This device also has the ability to interface with low-voltage microcontrollers because of the presence of separate VIO pin supporting 1.65 V to 5.5 V. Bus supply voltage V_CC can be independent of V_IO and supports 3 to 5.5 V. All the features are packed in a tiny thermally efficient 16-VQFN package (3-mm x 3-mm)
  Figure 5-1 THVD1424 Block Diagram
• THVD1454 has a sub-set of features compared to THVD1424. THVD1454 is in space-saving 10-VSON package (3-mm × 3-mm) and is designed for only half-duplex networks. This device also has on-chip 120-Ω switchable termination across the bus pins and slew rate control. This device provides a excellent alternative to customers looking for pin compatibility with equivalent competition solutions.
  Figure 5-2 THVD1454 Block Diagram

Other unique features offered is:

Other unique features offered by both the devices are:

• Termination resistor across the bus pins can be enabled or disabled across the bus pins independent of the driver or receiver enable/disable states.
• Termination is tightly regulated over supply voltage 3 to 5.5 V, common mode voltage -7 V to 12 V and temperature -40°C to 125°C.
• The device can operate from 3.3 V or 5 V bus supply.
• Bus pins provide 1/8 unit load supporting 256 nodes on the bus.
• Failsafe receiver for bus open, short and idle conditions.
• Level 4 IEC 61000-4-2 ESD protection on bus pins: ±8 kV contact discharge/±15 kV air discharge.
• Glitch filter in receiver path for slow speed mode to filter out fast noise pulses.
• Extended industrial temperature range: -40°C to 125°C.
• Integrated protection such as bus short circuit current limiting, thermal shutdown and supply under-voltage.