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
External Frequency
Crystal
Reference
Parameter
Condition a
Min
Typ
Max
–
Min
Typ
Max
Unit
MHz b
Ω
Ω
Frequency
–
–
30
12
30
52
ESR
–
–
–
60
–
N/A
–
–
Input impedance
Resistive
Capacitive
Programmable
–
N/A
N/A
–
1M
–
–
–
4.7
1
pF
Power dissipation
0.2
1
0.2
–
mW
Depends on external
reference input amplitude
400 c
0
Input voltage
AC-coupled analog signal
DC-coupled digital signal
–
–
N/A
N/A
–
–
1200
mVp-p
V
Output low
level
Output high
level
DC-coupled digital signal
Without trimming
–
N/A
+10
1.0
–
1.36
20
V
Frequency
tolerance d
–20
20
50
–20
+10
ppm
Initial frequency
tolerance trimming
range
–
–50
–
–
–50
40
–
50
60
ppm
%
Duty cycle
For 30 MHz clock
N/A
–
50
Broadcom®
Single-Chip IEEE 802.11™ a/b/g/n MAC/Baseband/Radio
Page 20
April 2, 2014 • 4319-DS05-R
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