DS75176

The CM8870PI provides full DTMF receiver capability by integrating both the bandsplit filter and digital decoder functions into a single 18-pin DIP. The filter section uses a switched capacitor technique for both high and low group filters and dial tone rejection. The CM8870 decoder uses digital counting techniques for the detection and decoding of all 16 DTMF tone pairs into a 4-bit code. This DTMF receiver minimizes external component count by providing an on-chip differential input ampli-fier, clock generator, and a latched three state interface bus. The on-chip clock generator requires only a low cost TV crystal or ceramic resonator as an external component.

Each part contains one driver and one receiver. The driver slew rates of the MAX485 is not limited, allowing them to transmit up to 2.5Mbps. All parts operate from a single 5V supply.The driver is short-circuit current limited and? protected against excessive power dissipation by thermal shutdown circuitry that places the driver outputs into a high-impedance state. The receiver input has a fail-safe feature that guarantees a logic-high output if the input is open circuit. The MAX485 is designed for half-duplex applications.

The?MCP2551?is a high-speed?Controller Area Network?(CAN), fault-tolerant?device that serves as the interface between a?CAN?protocol controller?and the physical bus. The MCP2551?device provides differential transmit and receive?capability for the CAN protocol controller, and is fully?compatible with the ISO-11898 standard, including 24V?requirements. It will operate at speeds of up to 1 Mb/s.

Typically, each node in a CAN system must have a?device to convert the digital signals generated by a?CAN controller to signals suitable for transmission over?the bus cabling (differential output). It also provides a?buffer between the CAN controller and the high-voltage?spikes that can be generated on the CAN bus by?outside sources (EMI, ESD, electrical transients, etc.).