BCM20713A1KUFBXG Datasheet, PDF (31/65 Pages) Cypress Semiconductor – Single-Chip Bluetooth Transceiver and Baseband Processor

BCM20713 Preliminary Data Sheet
Frequency References
Section 6: Frequency References
The BCM20713 uses two different frequency references for normal and low-power operational modes. An
external crystal or frequency reference driven by a Temperature Compensated Crystal Oscillator (TCXO) signal
is used to generate the radio frequencies and normal operation clocking. Either an external 32.768 kHz or fully
integrated internal Low-Power Oscillator (LPO) is used for low-power mode timing.
Crystal Interface and Clock Generation
The BCM20713 uses a fractional-N synthesizer to generate the radio frequencies, clocks, and data/packet
timing, enabling it to operate from any of a multitude of frequency sources. The source can be external, such as
a TCXO, or a crystal interfaced directly to the device.
The default frequency reference setting is for a 20 MHz crystal or TCXO. The signal characteristics for the
crystal interface are listed in Table 3 on page 30.
Table 3: Crystal Interface Signal Characteristics
Parameter
Acceptable frequencies
Crystal load capacitance
ESR
Power dissipation
Input signal amplitude
Signal type
Input impedance
Phase noise
@ 1 kHz
@ 10 kHz
@ 100 kHz
@ 1 MHz
Auto-detection frequencies
when using external LPO^c
Tolerance without frequency
trimming^d
Initial frequency tolerance
trimming range
Crystal
External Frequency Reference Units
12–52 MHz in 2 ppm^a steps
12–52 MHz in 2 ppm^a steps
–
12 (typical)
N/A
pF
60 (max)
–
Ω
200 (max)
–
W
N/A
400 to 2000
mVp-p
2000 to 3300 (requires a 10 pF DC
blocking capacitor to attenuate the
signal)
N/A
Square-wave or sine-wave
–
N/A
1
MΩ
2
pF
N/A
–
–
N/A
< –120^b
dBc/Hz
N/A
< –131^b
dBc/Hz
N/A
< –136^b
dBc/Hz
N/A
< –136^b
dBc/Hz
12, 13, 14.4, 15.36, 16.2, 16.8, 12, 13, 14.4, 15.36, 16.2, 16.8, 18, MHz
18, 19.2, 19.44, 19.68, 19.8, 20, 19.2, 19.44, 19.68, 19.8, 20, 24,
24, 26, 33.6, 37.4, and 38.4
26, 33.6, 37.4, and 38.4
±20
±20
ppm
±50
±50
ppm
a. The frequency step size is approximately 80 Hz resolution.
Broadcom^®
December 21, 2015 • 20713-DS102-R
Single-Chip Bluetooth Transceiver and Baseband Processor
Page 30
BROADCOM CONFIDENTIAL