ML5800

DS5800-F-04

FINAL DATASHEET

JULY 2006

13

TRANSMIT MODE

In TRANSMIT mode, the PLL loop is closed to eliminate frequency drift. A two-port modulator modulates both the VCO

and the fractional-N PLL. The VCO is directly modulated with filtered FSK transmit data. The PLL is driven by a sigma-

delta modulator, which ensures that the PLL follows the mean frequency of the modulated VCO.

PLL Programming & Channel Selection

The ML5800 PLL is programmed with a 14bit word to set the RF center frequency of the radio. The channel frequency

Where N is the “integer” portion and P is the “fractional” portion of the synthesizer. See Register 1 Description for

further details on how to program the channel frequency plan in the control register.