47.6.1 Crystal Oscillator (XOSC) Characteristics

The following table describes the characteristics for the oscillator when a digital clock is applied on XIN.

Table 47-20. Digital Clock Characteristics
Symbol	Parameter	Condition	Min	Typ.	Max.	Units
f_CPXIN	XIN clock frequency	Digital mode	-	-	48	MHz
DC_XIN⁽¹⁾	XIN clock duty cycle	Digital mode	40	50	60	%

These values are based on simulation and are not covered by test or characterization

The following table describes the characteristics for the oscillator when a crystal is connected between XIN and XOUT as shown in the figure below. The user must choose a crystal oscillator where the crystal load capacitance C_L is within the range given in the table. The exact value of C_L can be found in the crystal data sheet. The capacitance of the external capacitors (C_LEXT) can then be computed as follows:

C_{LEXT} = 2 (C_{L} + - C_{STRAY} - C_{SHUNT})

where,

C_STRAY is the capacitance of the pins and PCB, C_SHUNT is the shunt capacitance of the crystal.

Table 47-21. Multi Crystal Oscillator Electrical Characteristics ⁽¹⁾
Symbol	Parameter	Conditions	Min.	Typ.	Max.	Units
Fout	Crystal oscillator frequency		0.4	-	32	MHz
ESR	Crystal Equivalent Series Resistance - SF = 3	F = 0.455 MHz CL = 100 pF XOSC.GAIN = 0	-	-	443	Ω
		F = 2 MHz CL = 20 pF XOSC.GAIN=0	-	-	383
		F = 4 MHz CL = 20 pF XOSC.GAIN = 1	-	-	218
		F = 8 MHz CL= 20 pF XOSC.GAIN = 2	-	-	114
		F = 16 MHz CL=20 pF XOSC.GAIN = 3	-	-	58
		F = 32 MHz CL= 12 pF XOSC.GAIN = 4	-	-	62
Cxin	Parasitic load capacitor		-	6.7	-	pF
Cxout	Parasitic load capacitor		-	4.1	-	pF
Tstart	Startup time	F = 2 MHz CL=20 pF XOSC.GAIN = 0	-	12.3	48.7	KCycles
		F = 4 MHz CL= 20 pF XOSC.GAIN = 1	-	8.2	30.1
		F = 8 MHz CL=20 pF XOSC.GAIN = 2	-	6.2	19.9
		F = 16 MHz CL= 20 pF XOSC.GAIN = 3	-	10.8	30.1
		F = 32 MHz CL= 12 pF XOSC.GAIN = 4	-	8.7	23.6

These values are based on characterization.