BCM4319 Preliminary Data Sheet
External Frequency Reference
Figure 5: Recommended Oscillator Configuration
C
X T A L I N
a
10 – 33 pF
30 MHz 10
ppm
C
X T A L O U T
a
10 – 33 pF
a. The precise value of load capacitance to center the
frequency tolerance is dependent on board layout; see
Broadcom reference schematics for exact values.
External Frequency Reference
An external frequency reference generated by a TCXO may be directly connected to the XTALIN pin on the
BCM4319 as shown in Figure 6. The external frequency reference input is designed to not change the loading
on the TCXO when the BCM4319 is powered up or powered down.
Figure 6: Recommended TCXO Connection
TCXO
33 pF-1000 pF *
XTALIN
No Connection
XTALOUT
* Recommended value is 100 pF.
Higher values produce a longer start-up time.
Frequency Selection
For SDIO mode, any frequency within the ranges specified for the crystal and TCXO reference may be used.
These include the standard handset reference frequencies of 12, 13, 14.4, 16.2, 16.8, 18, 19.2, 19.44, 19.68,
19.8, 20, 24, 26, 30, 38.4, and 52 MHz, plus any other frequency in this range. The BCM4319 must have the
reference frequency set correctly in order for any of the UART interfaces to function properly, since all bit timing
is derived from the reference frequency.
Broadcom®
Single-Chip IEEE 802.11™ a/b/g/n MAC/Baseband/Radio
Page 22
April 2, 2014 • 4319-DS05-R
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