SM320F2812-HT Datasheet, PDF (63/155 Pages) Texas Instruments – Digital Signal Processor

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SM320F2812-HT
SGUS062A – JUNE 2009 – REVISED APRIL 2010
ADC 16-Channel Analog Inputs
Test Pin
ADCINA[7:0]
ADCINB[7:0]
ADCLO
ADCBGREFIN
ADC External Current Bias Resistor
ADC Reference Positive Input
ADC Reference Medium Input
ADCRESEXT
ADCREFP
ADCREFM
Analog Input 0−3 V With Respect to ADCLO
Connect to Analog Ground
24.9 kW/20 kW (See Note C)
1 mF − 10 mF
1 mF −10 mF
2 V (See
Note D)
1V
ADC Analog Power
ADC Reference Power
V_DDA1
V_DDA2
V_SSA1
V_SSA2
AVDDREFBG
AVSSREFBG
ADC Analog I/O Power
ADC Digital Power
V_DDAIO
V_SSAIO
V_DD1
V_SS1
Analog 3.3 V
Analog 3.3 V
Analog 3.3 V
Analog 3.3 V
Analog Ground
1.8 V Can use the same 1.8-V (or 1.9-V)
Digital Ground supply as the digital core but separate the
two with a ferrite bead or a filter
NOTES: A. External decoupling capacitors are recommended on all power pins.
B. Analog inputs must be driven from an operational amplifier that does not degrade the ADC performance.
C. Use 24.9 kΩ for ADC clock range 1 − 18.75 MHz; use 20 kΩ for ADC clock range 18.75 − 25 MHz.
D. It is recommended that buffered external references be provided with a voltage difference of (ADCREFP−ADCREFM)
= 1 V $ 0.1% or better.
External reference is enabled using bit 8 in the ADCTRL3 Register at ADC power up. In this mode, the accuracy of
external reference is critical for overall gain. The voltage ADCREFP−ADCREFM determines the overall accuracy. Do
not enable internal references when external references are connected to ADCREFP and ADCREFM. See the
TMS320x281x DSP Analog-to-Digital Converter (ADC) Reference Guide (literature number SPRU060) for more
information.
Figure 4-6. ADC Pin Connections With External Reference
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Peripherals
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