37.9 Oscillators and Clocks

Operating conditions:
  • VDD = 3V, except where specified otherwise
Table 37-12. Internal Oscillator (OSC20M) Characteristics
Symbol Description Condition Min. Typ. Max. Unit
fOSC20M Accuracy with 16 MHz and 20 MHz frequency selection relative to the factory-stored frequency value

Factory calibrated
VDD=3V(1)

T=[0, 70]°C,
VDD=[1.8, 4.5]V(3)

 -2.0 - 2.0 %

Factory calibrated
VDD=5V(1)

T=[0, 70]°C,
VDD=[4.5, 5.5]V(3)

 -2.0 - 2.0
Accuracy with 16 MHz and 20 MHz frequency selection Factory calibrated T=25°C, 3.0V -3.0 - 3.0 %

T=[0, 70]°C,
VDD=[1.8, 3.6]V(3)

 -4.0 - 4.0
Full operation range(3) -5.0 - 5.0
fCAL User calibration range OSC20M(2) = 16 MHz 14.5 - 17.5 MHz
OSC20M(2) = 20 MHz 18.5 - 21.5
%CAL Calibration step size - 1.5 - %
DC Duty cycle - 50 - %
Tstart Start-up time Within 2% accuracy - 8 - µs
Note:
  1. See the description of OSC20M on calibration.
  2. Oscillator frequencies above speed specification must be divided so that CPU clock always is within specification.
  3. These values are based on characterization and not covered by production test limits.
Table 37-13. 32.768 kHz Internal Oscillator (OSCULP32K) Characteristics
Symbol Description Condition Condition Min. Typ. Max. Unit
fOSCULP32K Accuracy Factory calibrated T=25°C, 3.0V -3 - 3 %

T=[0, 70]°C,
VDD=[1.8,  3.6]V(1)

 -10 - 10
Full operation range(1) -30 - 30
DC Duty cycle - 50 - %
Tstart Start-up time - 250 - µs
Note:
  1. These values are based on characterization and not covered by production test limits.
Table 37-14. 32.768 kHz External Crystal Oscillator (XOSC32K) Characteristics
Symbol Description Condition Min. Typ. Max. Unit
Fout Frequency - 32.768 - kHz
Tstart Start-up time CL=7.5 pF - 300 - ms
CL Crystal load capacitance 7.5 - 12.5 pF
CTOSC1 Parasitic capacitor load - 5.5 - pF
CTOSC2 - 5.5 - pF
ESR Equivalent Series Resistance - Safety Factor=3 CL=7.5 pF - - 80 kΩ
CL=12.5 pF - - 40
Figure 37-2. External Clock Waveform Characteristics
Table 37-15. External Clock Characteristics
Symbol Description Condition VDD=[1.8, 5.5]V VDD=[2.7, 5.5]V VDD=[4.5, 5.5]V Unit
Min. Max. Min. Max. Min. Max.
fCLCL Frequency 0 5.0 0.0 10.0 0.0 20.0 MHz
tCLCL Clock Period 200 - 100 - 50 - ns
tCHCX High Time 80 - 40 - 20 - ns
tCLCX Low Time 80 - 40 - 20 - ns