BCM43455 Preliminary Data Sheet
External Frequency Reference
Table 2: Crystal Oscillator and External Clock—Requirements and Performance (Cont.)
External Frequency
Crystala
Referenceb c
Parameter
Conditions/Notes
Min. Typ. Max. Min. Typ. Max. Units
WRF_XTAL_XOP
Input high level
DC-coupled digital signal
–
–
–
1.0
–
1.26
V
WRF_XTAL_XOP
input voltage
(see Figure 6 on
page 30)
IEEE 802.11a/b/g operation only –
–
–
400
–
1200 mV
p-p
WRF_XTAL_XOP
input voltage
(see Figure 6 on
page 30)
IEEE 802.11n/ac AC-coupled
analog input
–
–
–
1
–
–
V
p-p
Duty cycle
37.4 MHz clock
–
–
–
–
–
–
–
–
40
–
50
–
60
%
g
37.4 MHz clock at 10 kHz offset
–129 dBc/Hz
–136 dBc/Hz
Phase Noise
37.4 MHz clock at 100 kHz offset –
37.4 MHz clock at 10 kHz offset
37.4 MHz clock at 100 kHz offset –
37.4 MHz clock at 10 kHz offset
37.4 MHz clock at 100 kHz offset –
–
–
(IEEE 802.11b/g)
g
–
–
–
–
–
–
–
–
–
–137 dBc/Hz
–144 dBc/Hz
Phase Noise
(IEEE 802.11a)
g
–
–
–
–
–
–
–
–
–
–134 dBc/Hz
–141 dBc/Hz
Phase Noise
(IEEE 802.11n,
2.4 GHz)
g
37.4 MHz clock at 10 kHz offset
–
–
–
–
–
–
–
–
–
–142 dBc/Hz
–149 dBc/Hz
Phase Noise
37.4 MHz clock at 100 kHz offset –
(IEEE 802.11n,
5 GHz)
g
37.4 MHz clock at 10 kHz offset
–
–
–
–
–
–
–
–
–
–148 dBc/Hz
–155 dBc/Hz
Phase Noise
37.4 MHz clock at 100 kHz offset –
(IEEE 802.11ac,
5 GHz)
a. (Crystal) Use WRF_XTAL_XON and WRF_XTAL_XOP.
b. See “External Frequency Reference” on page 30 for alternative connection methods.
c. For a clock reference other than 37.4 MHz, 20 × log10(f/ 37.4) dB should be added to the limits, where f = the
reference clock frequency in MHz.
d. BT_TM6 should be tied low for a 52 MHz clock reference. For other frequencies, BT_TM6 should be tied high.
Note that 52 MHz is not an auto-detected frequency using the LPO clock.
e. The frequency step size is approximately 80 Hz resolution.
f. It is the responsibility of the equipment designer to select oscillator components that comply with these
specifications.
g. Assumes that external clock has a flat phase noise response above 100 kHz.
Broadcom®
November 5, 2015 • 43455-DS109-R
Page 31
BROADCOM CONFIDENTIAL
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