BCM4319XKUBGT Datasheet, PDF (21/84 Pages) Cypress Semiconductor – Single-Chip IEEE 802.11™ a/b/g/n MAC/Baseband/ Radio with Integrated SDIO and USB Interfaces

BCM4319 Preliminary Data Sheet
Frequency References
Section 3: Frequency References
The BCM4319 uses the following frequency references for normal and low-power operational modes:
• An external crystal or external frequency reference driven by a TCXO signal is used for generating all radio
frequencies and normal operation clocking.
• An internal 32.768 kHz sleep clock is provided for use by the PMU during low power states.
Crystal Interface and Clock Generation
The BCM4319 uses a fractional-N synthesizer to generate the radio frequencies, clocks, and data/packet timing.
This enables it to operate using numerous frequency references derived from an external source such as a
TCXO or a crystal connected directly to the BCM4319. The default frequency reference is a 30 MHz, 10 ppm
crystal or TCXO. The requirements and characteristics for the crystal circuit and external frequency reference
are listed in Table 1.
Table 1: Crystal Oscillator and External Frequency Reference Specifications
Parameter
Condition ^a
Min
Frequency
–
–
ESR
Input impedance
Power dissipation
Input voltage
–
–
Resistive
–
Capacitive
–
Programmable
0.2
Depends on external
reference input amplitude
AC-coupled analog signal –
Output low
level
DC-coupled digital signal –
Output high
level
DC-coupled digital signal –
Frequency
Without trimming
–20
tolerance ^d
Initial frequency
–
–50
tolerance trimming
range
Duty cycle
For 30 MHz clock
–
Crystal
Typ Max
30
–
–
60
N/A
N/A
–
1
N/A
N/A
N/A
+10 20
–
50
N/A –
External Frequency
Reference
Min Typ Max Unit
12
30
52
MHz ^b
–
N/A –
Ω
1M –
–
Ω
–
4.7 pF
0.2 –
1
mW
400 ^{c –}
0
–
1.0 –
–20 +10
1200
mV_p-p
V
1.36 V
20
ppm
–50 –
50
ppm
40
50
60
%
Broadcom^®
April 2, 2014 • 4319-DS05-R
Single-Chip IEEE 802.11™ a/b/g/n MAC/Baseband/Radio
Page 20