Crystal Oscillator Characteristics

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

CLEXT=2CL+−CSTRAY−CSHUNT

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

Table 1. Crystal Oscillator Characteristics
Symbol	Parameter	Conditions	Min.	Typ.	Max.	Units
f_OUT	Crystal oscillator frequency		0.4	-	32	MHz
ESR	Crystal Equivalent Series Resistance Safety Factor = 3 The AGC doesn’t have any noticeable impact on these measurements.	f = 0.455 MHz, C_L = 100pF XOSC.GAIN = 0	-	-	5.6K	Ω
		f = 2MHz, C_L = 20pF XOSC.GAIN = 0	-	-	416
		f = 4MHz, C_L = 20pF XOSC.GAIN = 1	-	-	243
		f = 8 MHz, C_L = 20pF XOSC.GAIN = 2	-	-	138
		f = 16 MHz, C_L = 20pF XOSC.GAIN = 3	-	-	66
		f = 32MHz, C_L = 18pF XOSC.GAIN = 4	-	-	56
C_XIN	Parasitic capacitor load		-	5.9	-	pF
C_XOUT	Parasitic capacitor load		-	3.2	-	pF
	Current Consumption	f = 2MHz, C_L = 20pF, AGC off	27	65	85	μA
		f = 2MHz, C_L = 20pF, AGC on	14	52	73
		f = 4MHz, C_L = 20pF, AGC off	61	117	150
		f = 4MHz, C_L = 20pF, AGC on	23	74	100
		f = 8MHz, C_L = 20pF, AGC off	131	226	296
		f = 8MHz, C_L= 20pF, AGC on	56	128	172
		f = 16MHz, C_L = 20pF, AGC off	305	502	687
		f = 16MHz, C_L = 20pF, AGC on	116	307	552
		f = 32MHz, C_L = 18pF, AGC off	1031	1622	2200
		f = 32MHz, C_L = 18pF, AGC on	278	615	1200
t_STARTUP	Start-up time	f = 2MHz, C_L = 20pF, XOSC.GAIN = 0, ESR = 600Ω	-	14K	48K	cycles
		f = 4MHz, C_L = 20pF, XOSC.GAIN = 1, ESR = 100Ω	-	6800	19.5K
		f = 8 MHz, C_L = 20pF, XOSC.GAIN = 2, ESR = 35Ω	-	5550	13K
		f = 16 MHz, C_L = 20pF, XOSC.GAIN = 3, ESR = 25Ω	-	6750	14.5K
		f = 32MHz, C_L = 18pF, XOSC.GAIN = 4, ESR = 40Ω	-	5.3K	9.6K

Figure 1. Oscillator Connection