36.9 Oscillators and Clocks

Operating conditions:
  • VDD = 3V, except where specified otherwise
Table 36-12. Internal Oscillator (OSC20M) Characteristics
SymbolDescriptionConditionMin.Typ.Max.Unit
fOSC20MAccuracy 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 selectionFactory calibratedT = 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
fCALUser calibration rangeOSC20M(2) = 16 MHz14.5-17.5MHz
OSC20M(2) = 20 MHz18.5-21.5
%CALCalibration step size -1.5-%
DCDuty cycle -50-%
TStartStart-up timeWithin 2% accuracy-8-µs
Note:
  1. See the description of OSC20M on calibration.
  2. Oscillator frequencies above speed specification must be divided so that the CPU clock always is within specification.
  3. These values are based on characterization and not covered by production test limits.
Table 36-13. 32.768 kHz Internal Oscillator (OSCULP32K) Characteristics
SymbolDescriptionConditionMin.Typ.Max.Unit
fOSCULP32KAccuracyFactory calibratedT = 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
DCDuty cycle-50-%
TStartStart-up time-250-µs
Note:
  1. These values are based on characterization and not covered by production test limits.
Table 36-14. 32.768 kHz External Crystal Oscillator (XOSC32K) Characteristics
SymbolDescriptionConditionMin.Typ.Max.Unit
FoutFrequency -32.768-kHz
TStartStart-up timeCL = 7.5 pF-300-ms
CLCrystal load capacitance 7.5-12.5pF
CTOSC1Parasitic capacitor load -5.5-pF
CTOSC2-5.5-pF
ESREquivalent Series Resistance - Safety Factor = 3CL = 7.5 pF--80kΩ
CL = 12.5 pF--40
Figure 36-3. External Clock Waveform Characteristics
Table 36-15. External Clock Characteristics
SymbolDescriptionConditionVDD = [1.8, 5.5]VVDD = [2.7, 5.5]VVDD = [4.5, 5.5]VUnit
Min.Max.Min.Max.Min.Max.
fCLCLFrequency 05.00.010.00.020.0MHz
tCLCLClock period 200-100-50-ns
tCHCXHigh time 80-40-20-ns
tCLCXLow time 80-40-20-ns