MICROCHIP HYC9088AR-LF

The HYC9088A Twisted Pair and Coaxial Compatible High Impedance Transceiver (HIT) is a hybrid module that interfaces an ARCNET Local Area Network controller to one twisted pair or coaxial cable. The HIT interfaces directly with Standard Microsystems Corporation's ARCNET LAN controllers operating at 2.5 Mbps and connects to a variety of shielded and unshielded twisted pair or coaxial cables via an on - board transformer. The network topologies supported by the HIT are daisy chain, star, and bus configurations. During data transmission, the HIT converts the digital pulse information provided by the ARCNET LAN controller into analog signals and drives them onto the cable. The transmitted signals are filtered to eliminate undesirable frequencies. The receiver section of the HYC9088 identifies dipulse signals on the cable and converts them into TTL signals to be supplied to the ARCNET LAN controller. The HIT supports ARCNET's Dipulse Encoding Scheme and, is 100% compatible with all existing coax - based ARCNET networks. This provides an ARCNET network designer with flexibility to easily combine coax and twisted pair cabling. The HYC9088A HIT integrates a host of discrete components into a hybrid module and provides the Local Area Network designer with space and cost savings as well as the enhanced reliability of a single component. Since the HIT is a high impedance transceiver, it does not disturb the characteristic impedance of the cable used to interconnect ARCNET nodes. The two far ends of the twisted pair cable must be terminated using terminating resistors equal to the characteristic impedance of the cable. The HIT is made up of a transmit section and a receive section. The ARCNET LAN controller transmits a logic "1" by generating two 100 ns non - overlapping negative pulses, nPULSE1 and nPULSE2. These signals are converted by the HIT into a 200 ns dipulse signal. The HIT shapes the 200 ns signal into a single cycle of a 5 MHz sine - wave and filters higher frequency components. The dipulse signal is then transformer - coupled onto the cable and has a minimum voltage output of 16 Volts peak - to - peak. The exact output voltage of the HIT will vary depending on the characteristic impedance of the cable used. The driving circuitry of the HIT has been designed to present a high impedance on the cable in order to minimize loading. The DISABLE input of the HYC9088 can be used to prevent the device from transmitting.

• ARCNET on Twisted Pair or Coaxial Cable
• Supports Star, Bus, and Daisy Chained Drives
• Shielded and Unshielded Twisted Pair Cable Configurations or Coaxial Cable
• Enhanced Built - in Filters for Reduced EMI
• Compatible with Existing ARCNET Installations
• Twenty Pin Single In - Line Package
• 2.5 Mbps operation
• Straight or Right Angle Lead Frame
• New Reduced Size