SI5366 Datasheet, PDF (9/20 Pages) Silicon Laboratories – PRECISION CLOCK MULTIPLIER/JITTER ATTENUATOR

Pin #
13
57
16
17
20
21
22
Si5366
Pin Name
CS0_C3A
CS1_C4A
XA
XB
FS_SW
FS_ALIGN
AUTOSEL
Table 3. Si5366 Pin Descriptions (Continued)
I/O Signal Level
Description
I/O LVCMOS Input Clock Select/CKINn Active Clock Indicator.
If manual clock selection mode is chosen (AUTOSEL = L), the
CS[1:0] pins function as the manual input clock selector con-
trol.
CS[1:0]
Active Input Clock
00
CKIN1
01
CKIN2
10
CKIN3
11
CKIN4
These inputs are internally deglitched to prevent inadvertent
clock switching during changes in the CSn input state.
If automatic clock detection is chosen (AUTOSEL = M or H),
these pins function as the CKINn active clock indicator output.
0 = CKINn is not the active input clock.
1 = CKINn is currently the active input clock to the PLL.
This pin has a weak pull-down.
I
ANALOG External Crystal or Reference Clock.
External crystal should be connected to these pins to use inter-
nal oscillator based reference. If external reference is used,
apply reference clock to XA input and leave XB pin floating.
External reference must be from a high-quality clock source
(TCXO, OCXO). Frequency of crystal or external clock is set by
the RATE pin. When used with an external 38.88 MHz refer-
ence, AC couple to XA and leave XB as a no connect.
I
LVCMOS FSYNC Inputs to Clock Selection Enable.
If CK_CONF = 1, this pin enables the use of the CKIN3 and
CKIN4 loss-of-signal indicators as inputs to the clock selection
state machine.
0 = Do not use CKIN3 and CKIN4 LOS indicators as inputs to
the clock selection state machine.
1 = Use CKIN3 and CKIN4 LOS indicators as inputs to the
clock selection state machine.
This pin has a weak pull-down.
I
LVCMOS FSYNC Alignment Control.
If CK_CONF = 1, a logic high on this pin causes the FS_OUT
phase to be realigned to the rising edge of the currently active
input sync (CKIN3 or CKIN4).
0 = No realignment.
1 = Realignment.
This pin has a weak pull-down.
I
3-Level Manual/Automatic Clock Selection.
Three level input that selects the method of input clock selec-
tion to be used.
L = Manual.
M = Automatic non-revertive.
H = Automatic revertive.
Preliminary Rev. 0.2
9