SM320F28335-EP_12 Datasheet, PDF (146/167 Pages) Texas Instruments – Digital Signal Controller (DSC)

SM320F28335-EP
SPRS581D – JUNE 2009 – REVISED MAY 2012
www.ti.com
6.15 On-Chip Analog-to-Digital Converter
Table 6-49. ADC Electrical Characteristics (over recommended operating conditions)^{(1) (2)}
PARAMETER
DC SPECIFICATIONS⁽³⁾
MIN TYP MAX UNIT
Resolution
12
Bits
ADC clock
0.001
25 MHz
ACCURACY
INL (Integral nonlinearity)
1-12.5 MHz ADC clock (6.25 MSPS)
±1.5 LSB
DNL (Differential nonlinearity)⁽⁴⁾
Offset error ^{(5) (3)}
Overall gain error with internal reference ^{(6) (3)}
Overall gain error with external reference ⁽³⁾
12.5-25 MHz ADC clock
(12.5 MSPS)
±2 ^LSB
±1 LSB
±15
LSB
±30
LSB
±30
LSB
Channel-to-channel offset variation
±4
LSB
Channel-to-channel gain variation
±4
LSB
ANALOG INPUT
Analog input voltage (ADCINx to ADCLO) ⁽⁷⁾
0
3
V
ADCLO
–5
0
5 mV
Input capacitance
10
pF
Input leakage current
INTERNAL VOLTAGE REFERENCE ⁽⁶⁾
±5
μA
V_ADCREFP - ADCREFP output voltage at the pin based on
internal reference
1.275
V
V_ADCREFM - ADCREFM output voltage at the pin based on
internal reference
0.525
V
Voltage difference, ADCREFP - ADCREFM
0.75
V
Temperature coefficient
EXTERNAL VOLTAGE REFERENCE^{(6) (8)}
50
PPM/°C
V_ADCREFIN - External reference voltage input on ADCREFIN
pin 0.2% or better accurate reference recommended
ADCREFSEL[15:14] = 11b
ADCREFSEL[15:14] = 10b
ADCREFSEL[15:14] = 01b
1.024
V
1.500
V
2.048
V
AC SPECIFICATIONS
SINAD (100 kHz) Signal-to-noise ratio + distortion
67.5
dB
SNR (100 kHz) Signal-to-noise ratio
68
dB
THD (100 kHz) Total harmonic distortion
–79
dB
ENOB (100 kHz) Effective number of bits
10.9
Bits
SFDR (100 kHz) Spurious free dynamic range
83
dB
(1) Tested at 25 MHz ADCCLK.
(2) All voltages listed in this table are with respect to V_SSA2.
(3) ADC parameters for gain error and offset error are only specified if the ADC calibration routine is executed from the Boot ROM. See
Section 4.7.3 for more information.
(4) TI specifies that the ADC will have no missing codes.
(5) 1 LSB has the weighted value of 3.0/4096 = 0.732 mV.
(6) A single internal/external band gap reference sources both ADCREFP and ADCREFM signals, and hence, these voltages track
together. The ADC converter uses the difference between these two as its reference. The total gain error listed for the internal reference
is inclusive of the movement of the internal bandgap over temperature. Gain error over temperature for the external reference option will
depend on the temperature profile of the source used.
(7) Voltages above V_DDA + 0.3 V or below V_SS - 0.3 V applied to an analog input pin may temporarily affect the conversion of another pin.
To avoid this, the analog inputs should be kept within these limits.
(8) TI recommends using high precision external reference TI part REF3020/3120 or equivalent for 2.048-V reference.
146 Electrical Specifications
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