66.5.1 Main Oscillator Characteristics
| Symbol | Parameter | Conditions | Min | Typ | Max | Unit |
|---|---|---|---|---|---|---|
| fOSC | Operating Frequency |
FREQ(2) = 00, 11 FREQ = 01 FREQ = 10 |
8 12 16 |
– |
12 16 24 |
MHz |
| – | Duty Cycle | – | 40 | 50 | 60 | % |
| tSTART | Startup Time |
FREQ(2) = 00, 11 FREQ = 01 FREQ = 10 |
– | – |
18.5 10.5 6 |
ms |
| IDDON | Current Consumption (on VDDIO) |
@ 12 MHz @ 24 MHz |
– |
1.2 1.7 |
3.5 4 |
mA |
| IDD_STDBY | Standby Current | – | – | 0.02 | 0.1 | µA |
| CPARA | Internal Parasitic Capacitance(1) | From XIN to XOUT | 1.4 | 1.6 | 1.8 | pF |
| PON | Drive level |
FREQ = 00 FREQ = 01, 11 FREQ = 10 |
– | – |
150 300 400 |
µW |
Note:
- The values of external capacitors can
be determined by using the following formula:
CLEXT = (2 x CCRYSTAL) - CBOARD - (CPARA x 2)
where:
- CLEXT is the external capacitor value which must be soldered from XIN to GND and XOUT to GND
- CCRYSTAL is crystal targeted load
- CBOARD is the external board parasitic capacitance (from XIN to GND or XOUT to GND)
- CPARA is the internal parasitic capacitance
- The SFR_UTMICKTRIM.FREQ field defines the input frequency for the UTMI and the main oscillator. It is important to select the correct FREQ value because this has a direct influence on USB frequency.