The MC145193 is recommended for new designs and offers reduced power consumption. The counters are programmed via a synchronous serial port which is SPI compatible. The serial port is byte-oriented to facilitate control via an MCU. Due to the innovative BitGrabber PlusTM registers, the MC145193 may be cascaded with other peripherals featuring BitGrabber Plus without requiring leading dummy bits or address bits in the serial data stream. In addition, BitGrabber Plus peripherals may be cascaded with existing BitGrabberTM peripherals. The device features a singleended current source/sink phase detector A output and a doubleended phase detector B output. Both phase detectors have linear transfer functions (no dead zones). The maximum current of the singleended phase detector output is determined by an external resistor tied from the Rx pin to ground. This current can be varied via the serial port. Slewrate control is provided by a special driver designed for the REFout pin. This minimizes interference caused by REFout. This part includes a differential RF input that may be operated in a singleended mode. Also featured are onboard support of an external crystal and a programmable reference output. The R, A, and N counters are fully programmable. The C register (configuration register) allows the part to be configured to meet various applications. A patented feature allows the C register to shut off unused outputs, thereby minimizing system noise and interference.