The HI-8588-10 ARINC 429 bus interface receiver is similar to the HI-8588 with the exception that it allows an external 10 Kohm resistor in series with each ARINC input without affecting the ARINC input thresholds. The product is especially useful in applications where lightning protection circuitry is also required. In addition, the test inputs force both of the outputs to zero instead open circuit. The analog/digital CMOS product requires only a 5 volt supply and is available in a SO 8 pin package. Each side of the ARINC bus must be connected through a 10 Kohm series resistor in order for the chip to detect the correct ARINC levels. The typical 10 volt differential signal is translated and input to a window comparator and latch. The comparator levels are set so that with the external 10 Kohm resistors they are just below the standard 6.5 volt minimum ARINC data threshold and just above the standard 2.5 voltmaximum ARINC null threshold. The TESTA and TESTB inputs bypass the analog inputs for testing purposes. Also if TESTA and TESTB are both taken high, the digital outputs are forced to zero.