CGS702V Datasheet | National Semiconductor

Description The CGS702 is an off-the-shelf clock driver specifically designed for today’s high speed processors It provides low skew outputs which are produced at different frequencies from three fixed input references The CGS702 is a reduced EMI version of the CGS700 The XTALIN input pin is designed to be driven from three distinct crystal oscillators running at 25 MHz 33 MHz or 40 MHz The PLL using a charge pump and an internal loop filter multiplies this input frequency to create a maximum output frequency of four times the input The device includes a TRI-STATE control pin to disable the outputs while the PLL is still in lock This function allows testing the board without having to wait to acquire the lock once the testing is plete (Continued) Y Y Y Y Y Y Y Y Y Y Y Features Guaranteed and tested 500 ps pin-to-pin skew (TOSHL and TOSLH) on 1x outputs Pentium TM and Power PCTM patible Output buffer of nine drivers for large fanout 25 MHz - 160 MHz output frequency range Outputs operating at 4x 2x 1x of the reference frequency for multi-frequency bus applications Selectable output frequency Internal loop filter to reduce noise and jitter Separate Analog and digital VCC and Ground pins Low frequency test mode by disabling the PLL Implemented on National’s Core CMOS process Symmetric output current drive a 30 m A b 30 m A IOL IOH 28-pin PCC for optimum skew performance Guaranteed 2 k V ESD protection Reduced EMI pared to CGS700 (refer to EMI characteristics) Pin Description Connection Diagram PLCC Package Pin 1 2 3 Name VCC SKWSEL CLK4 VCC XTALIN GND CLK1 VCC CLK1 GND CLK1 2 1 0 Description Digital VCC Skew Test Selector Pin 4x Clock Output Digital VCC Crystal Oscillator Input Digital Ground 1x Clock Output Digital VCC 1x Clock Output Digital Ground 1x Clock Output Output TRI-STATE Control Skew Testing Pin 1x Clock Output Digital Ground 4 1x Clock Output Digital VCC External Test Clock Analog Ground Analog VCC External Clock MUX Selector Digital Ground 5 1x...