BCM43362KUBGT Datasheet, PDF (22/84 Pages) Cypress Semiconductor – Single-Chip IEEE 802.11™ b/g/n MAC/Baseband/Radio + SDIO

BCM43362 Data Sheet
External 32.768 kHz Low-Power Oscillator
External 32.768 kHz Low-Power Oscillator
The BCM43362 uses a secondary low-frequency sleep clock for low-power mode timing. Either the internal low-
precision LPO or an external 32.768 kHz precision oscillator is required. The internal LPO frequency range is
approximately 33 kHz ± 30% over process, voltage, and temperature, which is adequate for some applications.
However, one trade-off caused by this wide LPO tolerance is a small current consumption increase during power
save mode that is incurred by the need to wake up earlier to avoid missing beacons.
Whenever possible, the preferred approach is to use a precision external 32.768 kHz clock that meets the
requirements listed in Table 3.
Note: The BCM43362 will auto-detect the LPO clock. If it senses a clock on the EXT_SLEEP_CLK
pin, it will use that clock. If it doesn't sense a clock, it will use its own internal LPO.
• To use the internal LPO: Tie EXT_SLEEP_CLK to ground. Do not leave this pin floating.
• To use an external LPO: Connect the external 32.768 kHz clock to EXT_SLEEP_CLK.
Table 3: External 32.768 kHz Low-Power Oscillator Specifications
Symbol
Fr
f/fr
Parameter
Frequency
Frequency tolerance
Duty cycle –
Vol
Output low voltage
Voh
Output high voltage
Tr/Tf
Rise and fall time
–
Signal type
–
Clock jitter
–
Input impedance
–
Input amplitude
Condition/Notes
–
At 25°C
–20°C <Ta< +70°C
–30°C <Ta< +85°C
–
–
–
–
Digital
Integrated over 300 Hz to
15 kHz
Resistive
Capacitive
Fail safe, 3.3V digital I/O
Specification
Minimum Typical
–
32768
– 30
–
– 150
–
– 220
–
30
–
0
–
0.7 Vio –
–
–
–
–
–
–
Maximum Units
–
Hz
+30
ppm
+40
+40
70
%
0.2
V
Vio
V
100
ns
–
–
30
ns
10
–
–
–
–
–
–
MΩ
2
pF
3.63
V
Broadcom_®
February 13, 2015 • 43362-DS106-R
IEEE 802.11 b/g/n MAC/Baseband/Radio + SDIO
Page 21
BROADCOM CONFIDENTIAL