3.2 Crystal Recommendations
The crystals in the table below are recommended for use with Si5357. The crystals listed are 25 and 27 MHz frequencies. However,
when choosing any crystal frequency between 16-30 MHz, a crystal with with ESR less than (or equal to) 50 Ω and CL less than (or
equal to) 20 pF can be used with Si5357. When choosing crystals of 31-50 MHz frequencies, C0 should not exceed 2 pF, CL should not
exceed 10 pF and the ESR should not exceed 50 Ω.
Table 3.1. Recommended Crystals
Crystal Part Number
Make
Stability
CL
ESR
ECS-25-18-30B-AKN
ECS
30ppm
18pf
30 Ω
ECS-27-18-30B-AKN
30ppm
18pf
30 Ω
FOXSDLF/250FR-20
Fox
30ppm
20pf
30 Ω
FA-238V-25.000000MHz12.0+15.0-15.0
Epson
50ppm
12pf
50 Ω
ABM3B-25.000MHz-18-50-D1U
Abracon
20ppm
18pf
50 Ω
ABM3B-27.000MHz-18-50-D1U
20ppm
18pf
50 Ω
ABM3B-25.000MHz-18-60-D1U
30ppm
18pf
60 Ω
ABM3B-27.000MHz-18-60-D1U
30ppm
18pf
60 Ω
ABM3B-25.000MHz-12-50-D1U
10ppm
10pf
50 Ω
ABM3B-27.000MHz-12-50-D1U
10ppm
10pf
50 Ω
AA-25.000MALE-T
TXC
30ppm
12pf
50 Ω
AA-27.000MAGK-T
30ppm
20pf
50 Ω
FQ5032B-25.000
Fox
30ppm
20pf
50 Ω
FQ5032B-27.000
NX5032GA-25.000M-STD-CSK-4
NDK
30ppm
8pf
50 Ω
NX5032GA-25.000000MHZ-LN-CD-1
30ppm
8pf
70 Ω
NX5032GA-27M-STD-CSK-4
30ppm
8pf
50 Ω
NX5032GA-27.000000MHZ-LN-CD-1
30ppm
8pf
70 Ω
7A-25.000MAAE
TXC
30ppm
12pf
50 Ω
7A-25.000MAAJ
30ppm
18pf
50 Ω
7A-27.000MAAE
30ppm
12pf
50 Ω
7A-27.000MAAJ
30ppm
18pf
50 Ω
When a crystal input is used, it is strongly recommended that the internal load capacitances (CL in table 1) are enabled. CL is the total
capacitance load across the XA, XB nodes. Therefore, the individual capacitances on each node need to be 2*CL. The method to set
the CL is as follows:
1. Enable internal CL loading by setting the XOSC_CINT_ENA bit field.
2. The load on each node, (XA and XB), is set by writing to the register fields XOSC_CTRIM_XA, XOSC_CTRIM_XB re-spectively
using the equation below:
2 ×
CL
= 10
pF
+ 0.5
pF
×
XOSC
_
CTRIM
_
XA
(
XOSC
_
CTRIM
_
XA
=
XOSC
_
CTRIM
_
XB
)
Using internal CL is recommended because it:
• Reduces the interference from the crystal oscillation into the Si5357 PLL system and therefore keeps the phase noise at an optimal
performance level.
• Reduces PCB area.
Si5357 Reference Manual • Input Clocks
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
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Rev. 0.2 • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice • July 26, 2021
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