Receiver jitter tolerance-SATA spec. (CDR corner frequency)

sata jitter tolerance

In SATA specification, jitter is defined as the difference in time between a data transition and the associated Reference Clock event for Gen1x, Gen2i and Gen2x. SATA assumes a BER target of less than 10-12. The Reference Clock is extracted from a serial data stream using either a PLL (hardware) or a clock recovery algorithm (software).

Reference Clock PLL are defined as type 2 PLL with a -3 dB corner frequency fc3db = fBAUD / N. Several corner frequencies are provided in the jitter budget fc3db = fBAUD / 10 (Gen2i, Gen2m), fc3db = fBAUD / 500 (Gen2i, Gen2m), fc3db = fBAUD / 1667 (Gen1x, Gen2x).For Gen2i and Gen2m, transmitters and receivers shall meet fBAUD / 10 and fBAUD / 500 specifications.

How to calculate the technical origin of the number 1667? Is there some mathematical or technical explanation for it?

I have read the Annex C in MJSQ (Method for Jitter and Signal Quality) document, but I can't get the answer .
Thank you!!