BCM4356XKUBGT Datasheet, PDF (30/195 Pages) Cypress Semiconductor – Single-Chip 5G WiFi IEEE 802.11ac 2×2 MAC/ Baseband/Radio with Integrated Bluetooth 4.1, FM Receiver, and Wireless Charging

BCM4356 Advance Data Sheet
External Frequency Reference
External Frequency Reference
For operation in SDIO mode only, an alternative to a crystal (an external precision frequency reference) can be
used. The recommended default frequency is 52 MHz ±10 ppm, and it must meet the phase noise requirements
listed in Table 3.
If used, the external clock should be connected to the WRF_XTAL_IN pin through an external 1000 pF coupling
capacitor, as shown in Figure 8. The internal clock buffer connected to this pin will be turned OFF when the
BCM4356 goes into sleep mode. When the clock buffer turns ON and OFF there will be a small impedance
variation. Power must be supplied to the WRF_XTAL_VDD1P5 pin.
Figure 8: Recommended Circuit to Use with an External Reference Clock
Reference
Clock
1000 pF
NC
WRF_XTAL_IN
WRF_XTAL_OUT
Table 3: Crystal Oscillator and External Clock—Requirements and Performance
Parameter
Conditions/Notes
Frequency
Frequency
tolerance over the
lifetime of the
equipment,
including
temperature^f
Crystal load
capacitance
ESR
2.4G and 5G bands: IEEE
802.11ac operation, SDIO3.0,
and PCIe WLAN interfaces
2.4G and 5G bands, IEEE
802.11ac operation, PCIe
interface alternative frequency
5G band: IEEE 802.11n
operation only
2.4G band: IEEE 802.11n
operation, and both bands
legacy 802.11a/b/g operation
only
Without trimming
–
–
Crystal^a
External Frequency
Reference^{b, c}
Min. Typ. Max. Min. Typ. Max. Units
35 37.4 –
– 52
– MHz
– 40 –
–
–
– MHz
19 – 52 35 –
52 MHz
Ranges between 19 MHz and 52 MHz^{d, e}
–20 – 20 –20 –
20 ppm
– 12 –
–
–
–
– 60 –
–
– pF
–Ω
Broadcom^®
May 8, 2015 • 4356-DS103-R
BROADCOM CONFIDENTIAL
Page 29