7 on-chip analog-to-digital converter – Texas Instruments TMS320F2802 User Manual
Page 125
,
,
,
SPRS230N – OCTOBER 2003 – REVISED MAY 2012
6.10.7 On-Chip Analog-to-Digital Converter
Table 6-38. ADC Electrical Characteristics (over recommended operating conditions)
(1) (2)
PARAMETER
MIN
TYP
MAX
UNIT
DC SPECIFICATIONS
Resolution
12
Bits
ADC clock
60-MHz device
0.001
7.5
MHz
100-MHz device
0.001
12.5
100-MHz device (F2809 only)
0.001
25
ACCURACY
INL (Integral nonlinearity)
1–12.5 MHz ADC clock (6.25 MSPS)
±1.5
LSB
12.5–25 MHz ADC clock (12.5 MSPS)
±2
DNL (Differential nonlinearity)
(3)
±1
LSB
Offset error
(4)
–60
+60
LSB
Offset error with hardware trimming
±4
LSB
Overall gain error with internal reference
(5)
–60
+60
LSB
Overall gain error with external reference
–60
+60
LSB
Channel-to-channel offset variation
±4
LSB
Channel-to-channel gain variation
±4
LSB
ANALOG INPUT
Analog input voltage (ADCINx to ADCLO)
(6)
0
3
V
ADCLO
–5
0
5
mV
Input capacitance
10
pF
Input leakage current
±5
μ
A
INTERNAL VOLTAGE REFERENCE
(5)
V
ADCREFP
- ADCREFP output voltage at the pin
1.275
V
based on internal reference
V
ADCREFM
- ADCREFM output voltage at the pin
0.525
V
based on internal reference
Voltage difference, ADCREFP - ADCREFM
0.75
V
Temperature coefficient
50
PPM/°C
EXTERNAL VOLTAGE REFERENCE
(5) (7)
ADCREFSEL[15:14] = 11b
1.024
V
V
ADCREFIN
- External reference voltage input on
ADCREFIN pin 0.2% or better accurate
ADCREFSEL[15:14] = 10b
1.500
V
reference recommended
ADCREFSEL[15:14] = 01b
2.048
V
AC SPECIFICATIONS
SINAD (100 kHz) Signal-to-noise ratio +
67.5
dB
distortion
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 12.5 MHz ADCCLK.
(2)
All voltages listed in this table are with respect to V
SSA2
.
(3)
TI specifies that the ADC will have no missing codes.
(4)
1 LSB has the weighted value of 3.0/4096 = 0.732 mV.
(5)
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.
(6)
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.
(7)
TI recommends using high precision external reference TI part REF3020/3120 or equivalent for 2.048-V reference.
Copyright © 2003–2012, Texas Instruments Incorporated
Electrical Specifications
125
Product Folder Link(s):