Digital Clock Characteristics
The following table describes the characteristics for the oscillator when a digital clock
is applied on XIN.
| 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 1. 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.
| 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 |
Notes:
- 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.
| 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.