46.13.1 Crystal Oscillator (XOSC) Characteristics

Digital Clock Characteristics

The following table describes the characteristics for the oscillator when a digital clock is applied on XIN.
Table 46-44. Digital Clock Characteristics
Symbol Parameter Min. Typ. Max. Units
FXIN XIN clock frequency - - 24 MHz
DCXIN(1) XIN clock duty cycle 40 50 60 %
Note:
  1. These values are based on simulation. They are not covered by production test limits or characterization.

Crystal Oscillator Characteristics

The following Table describes the characteristics for the oscillator when a crystal is connected between XIN and XOUT.

Figure 46-3. Oscillator Connection

The user must choose a crystal oscillator where the crystal load capacitance CL is within the range given in the Table. The exact value of CL can be found in the crystal data sheet. The capacitance of the external capacitors (CLEXT) can then be computed as follows:

CLEXT = 2(CL - CPARA - CPCB - CSHUNT)

Where:

  • CPARA is the internal load capacitor parasitic between XIN and XOUT (CPARA = (CXIN * CXOUT)/(CXIN + CXOUT))
  • CPCB is the capacitance of the PCB
  • CSHUNT is the shunt capacity of the crystal.
Table 46-45. Multi Crystal Oscillator Electrical Characteristics
Symbol Parameter Conditions Min. Typ. Max Units
Fout Crystal oscillator frequency 0.4 - 32 MHz
ESR(2) Crystal Equivalent Series Resistance - SF = 3 F = 0,4MHz - CL=100 pF XOSC,GAIN=0 - - 5.6K Ω
F = 2MHz - CL=20 pF XOSC,GAIN=0, Cshunt=3.3pF - - 330
F = 4MHz - CL=20 pF XOSC,GAIN=1, Cshunt=2.5pF - - 240
F = 8MHz - CL=20 pF XOSC,GAIN=2, Cshunt=5.5pF - - 105
F = 16MHz - CL=20 pF XOSC,GAIN=3, Cshunt=4pF - - 60
F = 32MHz - CL=20 pF XOSC,GAIN=4, Cshunt=3.9pF - - 55
Cxin(2) Parasitic load capacitor - 6.7 - pF
Cxout(2) - 4.2 - pF
Tstart(2) Startup time F = 2MHz - CL=20 pF XOSC,GAIN=0, Cshunt=3.3pF - 15.6K 81.6K Cycles
F = 4MHz - CL=20 pF XOSC,GAIN=1, Cshunt=2.5pF - 6.3K 25.2K
F = 8MHz - CL=20 pF XOSC,GAIN=2, Cshunt=5.5pF - 6.2K 27.2K
F = 16MHz - CL=20 pF XOSC,GAIN=3, Cshunt=4pF - 7.7K 27.3K
F = 32MHz - CL=20 pF XOSC,GAIN=4, Cshunt=3.9pF - 6.0K 21K
CL(1) Crystal load capacitance 10 - 20 pF
Pon(1) Drive Level AMPGC=ON - - 100 uW
Note:
  1. These values are based on simulation. They are not covered by production test limits or characterization.
  2. These values are based on characterization. They are not covered in test limits in production.
Table 46-46. Power Consumption (1)
Symbol Parameter Conditions Ta Min. Typ. Max. Units
IDD Current consumption F=2MHz - CL=20pF XOSC,GAIN=0, VCC=3.3V AMPGC=OFF Max 85°C

Typ 25°C

 - 66 85 µA
AMPGC=ON - 62 99
F=4MHz - CL=20pF XOSC,GAIN=1, VCC=3.3V AMPGC=OFF - 107 140
AMPGC=ON - 70 101
F=8MHz - CL=20pF XOSC,GAIN=2, VCC=3.3V AMPGC=OFF - 200 261
AMPGC=ON - 118 153
F=16MHz - CL=20pF XOSC,GAIN=3, VCC=3.3V AMPGC=OFF - 436 581
AMPGC=ON - 247 329
F=32MHz - CL=20pF XOSC,GAIN=4, VCC=3.3V AMPGC=OFF - 1303 1902
AMPGC=ON - 627 940
Note:
  1. These values are based on characterization. They are not covered in test limits in production.