Document No. 002-14949 Rev. *E
Page 17 of 113
PRELIMINARY
CYW43353
3.4 External 32.768 kHz Low-Power Oscillator
The CYW43353 uses a secondary low-frequency clock for low-power-mode timing. An external 32.768 kHz precision oscillator is
required. Use a precision external 32.768 kHz clock that meets the requirements listed in
.
Table 3. External 32.768 kHz Sleep Clock Specifications
Parameter
LPO Clock
Units
Nominal input frequency
32.768
kHz
Frequency accuracy
±200
ppm
Duty cycle
30–70
%
Input signal amplitude
200–1800
mV, p-p
Signal type
Square-wave or sine-wave
–
Input impedance
1
1.
When power is applied or switched off.
>100k
<5
Ω
pF
Clock jitter (during initial start-up)
<10,000
ppm