O p e r a t i n g f r e q u e n c y

Operating frequency

The NS7520 is available in grades operating at three maximum operating frequencies: 36 MHz, 46 MHz, and 55 MHz. The operating frequency is set during bootstrap initialization, using pins A[8:0]. These address pins load the PLL settings register on powerup reset. A[8:7] determines IS (charge pump current); A[6:5] determines FS (output divider), and A[4:0] defines ND (PLL multiplier). Each bit in A[8:0] can be set individually.

See "Setting the PLL frequency," beginning on page 54, for more detailed information.

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N S 7 5 2 0 H a r d w a r e R e f e r e n c e , R e v . D 0 3 / 2 0 0 6

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Digi NS7520 manual Operating frequency