Si53xx-RM

The Si5316 can accept a CKIN1 input at a different frequency than the CKIN2 input. The frequency of one input clock can be 1x, 4x, or 32x the frequency of the other input clock. The output frequency is always equal to the lower of the two clock inputs and is set via the FRQSEL [1:0] pins. The frequency applied at each clock input is divided down by a pre-divider as shown in the Figure 1 on page 17. These pre-dividers must be set such that the two resulting clock frequencies, f3_1 and f3_2 must be equal and are set by the FRQSEL [1:0] pins. Input divider settings are controlled by the CK1DIV and CK2DIV pins, as shown in Table 14.

Table 14. Input Divider Settings

CKnDIV

N3n Input Divider

 

 

L

1

 

 

M

4

 

 

H

32

 

 

Table 15. Si5316 Bandwidth Values

FRQSEL[1:0] Nominal Frequency Values (MHz)

 

LL

LM

LH

ML

MM

MH

 

 

 

 

 

 

 

BW[1:0]

19.44 MHz

38.88 MHz

77.76 MHz

155.52 MHz

311.04 MHz

622.08 MHz

 

 

 

 

 

 

 

HM

100 Hz

100 Hz

100 Hz

100 Hz

100 Hz

100 Hz

 

 

 

 

 

 

 

HL

210 Hz

210 Hz

200 Hz

200 Hz

200 Hz

200 Hz

 

 

 

 

 

 

 

MH

410 Hz

410 Hz

400 Hz

400 Hz

400 Hz

400 Hz

 

 

 

 

 

 

 

MM

1.7 kHz

1.7 kHz

1.6 kHz

1.6 kHz

1.6 kHz

1.6 kHz

 

 

 

 

 

 

 

ML

7.0 kHz

7.0 kHz

6.8 kHz

6.7 kHz

6.7 kHz

6.7 kHz

 

 

 

 

 

 

 

CKIN1 ÷ 1, ÷ 4, ÷ 32

CKIN2 ÷ 1, ÷ 4, ÷ 32

f3

One-to-one

frequency ratio

DSPLL

f3 = Fout

Fout

Figure 24. Si5316 Divisor Ratios

Rev. 0.5

51

Page 51
Image 51
Silicon Laboratories SI5326, SI5369, SI5365 manual Input Divider Settings, Si5316 Bandwidth Values, CKnDIV N3n Input Divider