Texas Instruments TMS320F2802, TMS320F2809, TMS320F2808 On-Chip Analog-to-Digital Converter

TMS320F2809, TMS320F2808, TMS320F2806

TMS320F2802, TMS320F2801, TMS320C2802

TMS320C2801, TMS320F28016, TMS320F28015

www.ti.com SPRS230L –OCTOBER 2003 –REVISED DECEMBER 2009

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	MHz
	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	LSB
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	μA
INTERNAL VOLTAGE REFERENCE(5)
VADCREFP - ADCREFP output voltage at the pin			1.275		V
based on internal reference
VADCREFM - 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)
VADCREFIN - External reference voltage input on	ADCREFSEL[15:14] = 11b		1.024		V
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 VSSA2.

(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 VDDA + 0.3 V or below VSS - 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 © 2003–2009, Texas Instruments Incorporated	Electrical Specifications	125
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TMS320C2801 TMS320F28016 TMS320F28015