HANSCHIP semiconductor HX65HVD1787EIDRG

HX65HVD1787E is a +5.0V-powered RS-485/RS-422 transceiver with ±16kV ESD protection. It features a failsafe circuit that drives the receiver output to a logic high when the receiver inputs are open or shorted, or when all drivers connected to a terminated bus are disabled. The entire product family supports hot-plug capability, eliminating bus fault transients during power-up or hot insertion.

The HX65HVD1787E driver delivers an exceptionally large output voltage swing (exceeding 2.1V into a 54Ω load), ensuring higher noise margin. The driver's slew rate is unconstrained, enabling data rates up to 16Mbps.

HX65HVD1787E is designed for half-duplex communication. All devices feature 1/8 unit load receiver input impedance, allowing up to 256 transceivers on the bus.

HX65HVD1787E is available in 8-pin DIP and 8-pin SOP packages, with commercial or industrial temperature range options.

The HX65HVD1787E high-speed RS-485/RS-422 transceiver family integrates one driver and one receiver. These devices incorporate a failsafe circuit (refer to the Failsafe section) and hot-plug capability to support hot insertion without data transmission errors (refer to the Hot-Plug Feature section). The HX65HVD1787E driver has an unconstrained slew rate, enabling a maximum data rate of 16Mbps. All devices operate from a single +5.0V supply. The driver includes output short-circuit current limiting. A thermal shutdown circuit protects the driver against excessive power dissipation; upon entering thermal shutdown, the driver outputs are placed in a high-impedance state.

When a board is inserted into a live or active backplane (hot-plug insertion), differential disturbances on the data bus may cause data errors. During board insertion, the data communication processor undergoes a power-up sequence, during which the processor's logic output drivers are in a high-impedance state and cannot drive the DE and RE inputs of these devices to valid logic levels. When in the high-impedance state, the processor's logic drivers may exhibit leakage currents up to ±10μA, which can cause the transceiver's standard CMOS enable inputs to drift to incorrect logic levels. Additionally, board parasitic capacitance may couple VCC or GND to the enable inputs. Without hot-plug capability, these factors can erroneously enable the transceiver driver or receiver. The HX65HVD1787E hot-plug feature ensures that internal circuitry holds DE low and RE high during VCC ramp-up. After the initial power-up sequence is complete, the pull-down circuit is deactivated and the hot-plug inputs are reset.

As with other related devices from Mingxin, all pins incorporate ESD protection structures to safeguard the device against electrostatic discharge during handling and assembly. The driver outputs and receiver inputs of the HX65HVD1787E family provide additional ESD protection capability. Mingxin's engineers have developed dedicated circuit architectures to protect these pins, enabling them to withstand ±16kV ESD strikes per the IEC 61000-4-2 model. The ESD protection structures can withstand high ESD strikes under all operating conditions, including normal operation, shutdown, and power-off modes. ESD protection can be verified using different test methods. The HX65HVD1787E transmitter outputs and receiver inputs have been tested for protection under the following conditions:

• ±16kV, HBM (Human Body Model).
• ±16kV, air discharge method per IEC 61000-4-2.
• ±16kV, contact discharge method per IEC 61000-4-2.

• True fail-safe receiver with low-power shutdown mode
• DE and RE with hot-swap input structure
• +5.0V supply voltage, supports up to 256 transceivers on the bus
• I/O ports with enhanced ESD protection (±16kV IEC 61000-4-2 model)

• RS-422/RS-485 communication
• Digital electric/water meters, industrial control, industrial embedded computers and peripherals, security surveillance systems
• Routers and switches
• Instrumentation, level shifting
• EMI-sensitive transceiver applications