Operating Frequency - Digi NS7520B-1-C36 Hardware Reference Manual

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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