SI5369 Datasheet, PDF (75/84 Pages) Silicon Laboratories – ANY-FREQUENCY PRECISION CLOCK MULTIPLIER/JITTER ATTENUATOR

Si5369
Pin #
13
57
Pin Name
CS0_C3A
CS1_C4A
Table 10. Si5369 Pin Descriptions (Continued)
I/O Signal Level
Description
I/O LVCMOS Input Clock Select/CKIN3 or CKIN4 Active Clock Indicator.
Input: If manual clock selection is chosen, and if
CKSEL_PIN = 1, the CKSEL pins control clock selection and
the CKSEL_REG bits are ignored.
CS[1:0]
00
01
10
11
Active Input Clock
CKIN1
CKIN2
CKIN3
CKIN4
If CKSEL_PIN = 0, the CKSEL_REG register bits control this
function and these inputs tristate. If configured as inputs, these
pins must not float.
Output: If auto clock selection is enabled, then they serve as
the CKIN_n active clock indicator.
0 = CKIN3 (CKIN4) is not the active input clock
1 = CKIN3 (CKIN4) is currently the active input to the PLL
The CKn_ACTV_REG bit always reflects the active clock status
for CKIN_n. If CKn_ACTV_PIN = 1, this status will also be
reflected on the CnA pin with active polarity controlled by the
CK_ACTV_POL bit. If CKn_ACTV_PIN = 0, this output tristates.
16
XA
I ANALOG External Crystal or Reference Clock.
17
XB
External crystal should be connected to these pins to use inter-
nal oscillator based reference. Refer to Family Reference Man-
ual for interfacing to an external reference. External reference
must be from a high-quality clock source (TCXO, OCXO). Fre-
quency of crystal or external clock is set by the RATE pins.
29
CKIN4+
I
MULTI Clock Input 4.
30
CKIN4–
Differential clock input. This input can also be driven with a sin-
gle-ended signal. CKIN4 serves as the frame sync input associ-
ated with the CKIN2 clock when CK_CONFIG_REG = 1.
32
RATE0
I
3-Level External Crystal or Reference Clock Rate.
42
RATE1
Three level inputs that select the type and rate of external crys-
tal or reference clock to be applied to the XA/XB port. Refer to
the Family Reference Manual for settings. These pins have both
a weak pull-up and a weak pull-down; they default to M.
34
CKIN2+
I
MULTI Clock Input 2.
35
CKIN2–
Differential input clock. This input can also be driven with a sin-
gle-ended signal.
39
CKIN3+
I
MULTI Clock Input 3.
40
CKIN3–
Differential clock input. This input can also be driven with a sin-
gle-ended signal. CKIN3 serves as the frame sync input associ-
ated with the CKIN1 clock when CK_CONFIG_REG = 1.
44
CKIN1+
I
MULTI Clock Input 1.
45
CKIN1–
Differential clock input. This input can also be driven with a sin-
gle-ended signal.
Note: Internal register names are indicated by underlined italics, e.g., INT_PIN. See Si5369 Register Map.
Rev. 1.0
75