47.4.4 Sigma-Delta Analog-to-Digital Converter (SDADC) Characteristics

Table 47-8. Operating Conditions⁽¹⁾
Symbol	Parameters	Conditions		Min	Typ	Max	Unit
Res	Resolution	Differential mode		-	16	-	bits
Res	Resolution	Single-Ended mode		-	15	-	bits
CLK_SDADC	Sampling Clock Speed			1	-	6	MHz
CLK_SDADC_FS	Conversion rate			CLK_SDADC/4
fs	Output Data Rate	Free running mode		CLK_SDADC_FS / OSR
fs	Output Data Rate	Single conversion mode SKPCNT = N		(CLK_SDADC_FS / OSR) x (N+1)
OSR	Oversampling ratio	Differential mode		64	256	1024	Cycles
Vin	Input Conversion range	VREF<VDDANA-0.3V	Differential mode Gaincorr = 0x1	- VREF	-	VREF	V
		VREF<VDDANA-0.3V	Single-Ended mode⁽³⁾ Gaincorr = 0x1	0	-	VREF	V
		VREF>=VDDANA-0.3V	Differential mode Gaincorr = 0x1	-0.7xVREF	-	0.7xVREF	V
		VREF>=VDDANA-0.3V	Single-Ended mode⁽³⁾ Gaincorr = 0x1	0	-	0.7xVREF	V
Vref	Reference Voltage range			1	-	VDDANA	V
Vcom	Common mode voltage	Differential mode		0	-	VDDANA	V
Cin	Input capacitance			0.425	0.5	0.575	pF
Zin	Input impedance	Differential mode		1/(Cin x CLK_SDADC_FS)			kΩ
Zin	Input impedance	Single-Ended mode⁽³⁾		1/(Cin x CLK_SDADC_FS x 2)			kΩ
	Input anti-alias filter recommendation⁽²⁾	Rext		-	1.0	-	kΩ
	Input anti-alias filter recommendation⁽²⁾	Cext		3.3	-	10	nF

These are based on simulation. These values are not covered by test or characterization.
External Anti-alias filter must be placed in front of each SDADC input to ensure high-frequency signals to not alias into measurement bandwidth. Use capacitors of X5R type for DC measurement. or capacitors of COG or NPO type for AC measurement.
This mode corresponds to a differential mode where the selected AINNx pin is externally grounded.

Table 47-9. SDADC DC Performance: Differential Input Mode. Chopper ON⁽¹⁾
Symbol	Parameters	Conditions (2)	Min	Typ	Max	Unit
INL	Integral Non Linearity	CLK_SDADC = 3MHz VREF = 1.2V	-	+/-2.9	+/-3.9	LSB
INL	Integral Non Linearity	CLK_SDADC = 3MHz INT VREF = 5.5V	-	+/-8.4	+/-9.3	LSB
DNL	Differential Non Linearity	CLK_SDADC = 3MHz VREF = 1.2V	-	+/-1.5	+/-2.1	LSB
DNL	Differential Non Linearity	CLK_SDADC = 3MHz INT VREF = 5.5V	-	+/-1.7	+/-2.3	LSB
Eg	Gain Errors	CLK_SDADC = 3MHz VREF = 1.2V	-	+/-0.3	+/-1.9	%
Eg	Gain Errors	CLK_SDADC = 3MHz INT VREF = 5.5V	-	+/-0.3	+/-1.7	%
TCg	Gain Drift	CLK_SDADC = 3MHz VREF = 1.2V	-0.9	3.9	17.5	ppm/°C
Off	Offset Error	CLK_SDADC = 3MHz VREF = 1.2V	-	+/-2.3	+/-3.7	mV
Off	Offset Error	CLK_SDADC = 3MHz INT VREF = 5.5V	-	+/-0.3	+/-2.4	mV
Tco	Offset Error Drift	CLK_SDADC = 3MHz VREF = 1.2V	-1.4	0.01	0.6	uV/°C

OSR=256

Table 47-10. SDADC DC Performance: Differential Input Mode. Chopper OFF⁽¹⁾
Symbol	Parameters	Conditions (2)	Min	Typ	Max	Unit
INL	Integral Non Linearity	CLK_SDADC = 6MHz VREF = 1.2V	-	+/-5.5	+/-9.3	LSB
INL	Integral Non Linearity	CLK_SDADC = 6MHz INT VREF = 5.5V	-	+/-8.9	+/-10.1	LSB
DNL	Differential Non Linearity	CLK_SDADC = 6MHz VREF = 1.2V	-	+/-2.8	+/-4.1	LSB
DNL	Differential Non Linearity	CLK_SDADC = 6MHz INT VREF = 5.5V	-	+/-1.8	+/-3	LSB
Eg	Gain Errors	CLK_SDADC = 6MHz VREF = 1.2V	-	+/-0.6	+/-2.1	%
Eg	Gain Errors	CLK_SDADC = 6MHz INT VREF = 5.5V	-	+/-0.3	+/-1.7	%
TCg	Gain Drift	CLK_SDADC = 6MHz VREF = 1.2V	-19.7	2.2	20.9	ppm/°C
Off	Offset Error	CLK_SDADC = 6MHz VREF = 1.2V	-	+/-1.7	+/-14.3	mV
Off	Offset Error	CLK_SDADC = 6MHz INT VREF = 5.5V	-	+/-4.9	+/-13.2	mV
Tco	Offset Error Drift	CLK_SDADC = 6MHz VREF = 1.2V	-14	12.4	60	μV/°C
Input noise rms	AC Input noise rms	OSR = 256 VREF = 1.2V	-	19	20
Input noise rms	AC Input noise rms	OSR = 256 VREF = 5.5V	-	59	76	mVrms

OSR=256

Table 47-11. SDADC AC Performance: : Differential Input Mode⁽¹⁾
Symbol	Parameters	Conditions (2)	Min	Typ	Max	Unit
ENOB	Effective Number Of Bits	Ext ref = 1.2V	12	15.3	15.4	bits
ENOB	Effective Number Of Bits	Int Ref = 5.5V	12.9	13.1	14	bits
DR	Dynamic Range	Ext ref = 1.2V	90.5	92.4	93.2	dB
DR	Dynamic Range	Int Ref = 5.5V	83.0	95.6	97.0	dB
SNR	Signal to Noise Ratio	Ext ref = 1.2V	68.7	88.7	89	dB
SNR	Signal to Noise Ratio	Int Ref = 5.5V	83	95.6	97	dB
SINAD	Signal to Noise + Distortion Ratio	Ext ref = 1.2V	71.1	90.7	91.7	dB
SINAD	Signal to Noise + Distortion Ratio	Int Ref = 5.5V	77.1	78.6	83.2	dB
THD	Total Harmonic Distortion	Ext ref = 1.2V	-102.3	-94.6	-75.3	dB
THD	Total Harmonic Distortion	Int Ref = 5.5V	-99.9	-94.7	-85.4	dB

Values based on characterization.
OSR=256, Chopper OFF, Sampling Clock Speed at 6MHz.

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