10.1.8.9 12-bit ADC Characteristics

Table 10-54. ADC Power Supply and Voltage Reference Input Characteristics
Symbol	Parameter	Conditions	Min	Max	Unit
V_DDANA	Supply voltage range (VDDANA)	–	3.0	3.60	V
I_DDANA	Current consumption (VDDANA)⁽²⁾	Low speed – f_S ≤ 500 kS/s ADC_ACR.IBCTL = (00)₂	–	1.0	mA
I_DDANA	Current consumption (VDDANA)⁽²⁾	Full speed – f_S ≤ 1 MS/s ADC_ACR.IBCTL = (01)₂	–	1.8	mA
V_ADVREFP	ADVREFP input voltage range⁽¹⁾	–	2.4	V_DDANA	V
R_ADVREFP	ADVREFP input resistance to ground⁽²⁾	ADC on	7.2	12	kΩ
R_ADVREFP	ADVREFP input resistance to ground⁽²⁾	ADC off	1	–	MΩ
C_ADVREFP	Required bypass capacitor on ADVREFP	–	1	–	μF

The ADVREFN pin must be connected to the PCB ground plane.
Simulation data

Table 10-55. ADC Timing Characteristics
Symbol	Parameter	Conditions	Min	Max	Unit
f_CKADC	ADC clock frequency	Low speed – f_S ≤ 500 kS/s ADC_ACR.IBCTL = (00)₂	0.1	10	MHz
f_CKADC	ADC clock frequency	Full speed – f_S ≤ 1 MS/s ADC_ACR.IBCTL = (01)₂	0.2	20	MHz
t_CONV	ADC conversion time⁽¹⁾	–	20	–	t_CKADC
f_S	Sampling rate⁽²⁾	Low speed – f_S ≤ 500 kS/s ADC_ACR.IBCTL = (00)₂	–	0.5	MS/s
f_S	Sampling rate⁽²⁾	Full speed – f_S ≤ 1 MS/s ADC_ACR.IBCTL = (01)₂	–	1	MS/s
t_START	Start-up time⁽³⁾	–	–	5	μs
t_TRACK	Track and hold time⁽³⁾⁽⁴⁾	–	300	–	ns

Note:

t_CONV = t_CH + t_TRACK + 14 x t_CKADC with t_CKADC = 1 / f_CKADC.

t_CH = 0 when the ADC operates in the same input mode (Single-ended, Pseudo-differential or Differential) for the current conversion than for the previous one.

t_CH = 2 when the ADC input mode is changed to perform the current conversion.
f_S = 1 / t_CONV
Simulation data
See Track and Hold Time versus Source Impedance – Sampling Rate.

Table 10-56. ADC Analog Input Characteristics
Symbol	Parameter	Conditions	Min	Max	Unit
V_FS	Analog input full scale range ⁽¹⁾	ADC_CCR.DIFFx = 0	0	V_ADVREFP	V
V_FS	Analog input full scale range ⁽¹⁾	ADC_CCR.DIFFx = 1	-V_ADVREFP	V_ADVREFP	V
V_INCM	Common mode input range in Differential mode⁽²⁾	ADC_CCR.DIFFx = 1	0.4 x V_DDANA	0.6 x * V_DDANA	V
C_S	ADC sampling capacitance⁽³⁾	–	–	3	pF
C_{P_ADx}	ADx input parasitic capacitance⁽³⁾⁽⁴⁾	ADx pin configured as analog input	–	7	pF
R_ON	Internal series resistor⁽³⁾⁽⁴⁾	–	–	2	kΩ
Z_IN	Common mode input impedance⁽³⁾⁽⁵⁾	On ADx pin	1 / (f_S.C_S)	–	Ω

Note:

V_FS = (V_ADx - V_GNDANA) in Single-ended mode, V_FS = (V_ADx - V_AD11) in Pseudo-differential mode, and V_FS = (V_ADx - V_ADx+1) in Differential mode.
V_INCM = (V_ADx + V_ADx+1) / 2
Simulation data
With respect to the equivalent model of Figure 10-40
Assuming conversion on one single channel

Figure 10-39. Acquisition Path Block Diagram

For tracking time calculation, during the sampling phase of the converter, this acquisition path can be reduced to the equivalent model provided in the following figure, where:

R_ON = R_MUX + R_S
C_{P_ADX} = C_PX + C_{P_MUX}

Figure 10-40. Equivalent Model of the Acquisition Path

See Track and Hold Time versus Source Impedance – Sampling Rate for further details on how to use this model.

In the following table, unless otherwise specified, the specifications are provided for two speed operating ranges.

Source resistance = 50 Ω
ADC_EMR.OSR<2:0> = (000)₂
Low-speed
- f_CKADC = 10 MHz, f_S = 500 kS/s
- ADC_ACR.IBCTL = (00)₂
High-speed
- f_CKADC = 20 MHz, f_S = 1 MS/s
- ADC_ACR.IBCTL = (01)₂

Table 10-57. Static Performance Characteristics
Symbol	Parameter	Conditions	Min	Max	Unit
RES_ADC	Native ADC resolution	–	12		Bit
INL	Integral non-linearity	–	-3	3	LSB
DNL	Differential non-linearity	–	-2	2	LSB
OE	Offset error	–	-4	4	LSB
GE	Gain error	–	-4	4	LSB

Note:

In this table, errors are expressed in LSB where:
- LSB = V_ADVREF / 2¹² in Single-ended mode (ADC_CCR.DIFFx = 0 and ADC_PDR.PDIFFx = 0)
- LSB = V_ADVREF / 2¹¹ in Differential or Pseudo-differential mode (ADC_CCR.DIFFx = 1)
Error with respect to the best fit line method