Zakładka z wyszukiwarką danych komponentów |
|
Si5347B-D-GM Arkusz danych(PDF) 7 Page - Silicon Laboratories |
|
Si5347B-D-GM Arkusz danych(HTML) 7 Page - Silicon Laboratories |
7 / 55 page 3.5 External Reference (XA/XB) An external crystal (XTAL) is used in combination with the internal oscillator (OSC) to produce an ultra-low jitter reference clock for the DSPLLs and for providing a stable reference for the Free-run and Holdover Modes. A simplified diagram is shown in the figure below. The device includes internal XTAL loading capacitors, which eliminates the need for external capacitors and also has the benefit of reduced noise coupling from external sources. Refer to Table 5.12 Crystal Specifications1 on page 33 for crystal specifications. A crystal in the range of 48 MHz to 54 MHz is recommended for best jitter performance. Frequency offsets due to CL mismatch can be adjusted using the frequency adjustment feature, which allows frequency adjustments of ±200 ppm. The Si5347/46 Family Reference Manual provides additional information on PCB layout recommendations for the crystal to ensure optimum jitter performance. To achieve optimal jitter performance and minimize BOM cost, a crystal is recommended on the XA/XB reference input. For SyncE line card PLL applications (e.g. loop bandwidth set to 0.1 Hz), a TCXO is required on the XA/XB reference to minimize wander and to pro- vide a stable holdover reference. See the Si5347/46 Family Reference Manual for more information. Selection between the external XTAL or REFCLK is controlled by register configuration. The internal crystal loading capacitors (CL) are disabled in the REFCLK mode. Refer to Table 5.3 Input Clock Specifications on page 24 for REFCLK requirements when using this mode. The Si5347/46 Family Reference Manual provides additional information on PCB layout recommendations for the crystal to ensure optimum jitter perform- ance. A PREF divider is available to accommodate external clock frequencies higher than 54 MHz. Although the REFCLK frequency range of 25 MHz to 54 MHz is supported, frequencies in the range of 48 MHz to 54 MHz will achieve the best output jitter performance. OSC XB XA 48-54MHz XTAL 2xCL 2xCL Crystal Resonator Connection OSC XB XA 48-54MHz XO 100 Differential XO Connection OSC XB XA 48-54MHz XO Single-Ended XO Connection 2xCL 2xCL 2xCL Si5347/46 Si5347/46 Si5347/46 2xCL ÷PREF ÷PREF ÷PREF Figure 3.3. Crystal Resonator and External Reference Clock Connection Options Si5347/46 Rev D Data Sheet Functional Description silabs.com | Smart. Connected. Energy-friendly. Rev. 1.0 | 6 |
Podobny numer części - Si5347B-D-GM |
|
Podobny opis - Si5347B-D-GM |
|
|
Link URL |
Polityka prywatności |
ALLDATASHEET.PL |
Czy Alldatasheet okazała się pomocna? [ DONATE ] |
O Alldatasheet | Reklama | Kontakt | Polityka prywatności | Linki | Lista producentów All Rights Reserved©Alldatasheet.com |
Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
Family Site : ic2ic.com |
icmetro.com |