SPRS439M – JUNE 2007 – REVISED AUGUST 2012
shows the ADC pin-biasing for internal reference and
shows the ADC pin-biasing
for external reference.
ADCINA[7:0]
ADCINB[7:0]
ADCLO
ADCREFIN
ADC 16-Channel Analog Inputs
Analog input 0−3 V with respect to ADCLO
Connect to analog ground
Connect to analog ground if internal reference is used
22 k
2.2 μF
2.2 μF
(A)
(A)
ADC External Current Bias Resistor ADCRESEXT
ADC Reference Positive Output
ADC Reference Medium Output
ADCREFP
ADCREFM
V
DD1A18
V
DD2A18
V
SS1AGND
V
SS2AGND
V
DDA2
V
SSA2
Reference I/O Power
V
DDAIO
V
SSAIO
ADCREFP and ADCREFM should not
be loaded by external circuitry
ADC Analog Power Pin (1.9 V/1.8 V)
ADC Analog Power Pin (1.9 V/1.8 V)
ADC Analog Ground Pin
ADC Analog Ground Pin
ADC Analog Power Pin (3.3 V)
ADC Analog Ground Pin
ADC Analog Power Pin (3.3 V)
ADC Analog I/O Ground Pin
A.
B.
C.
TAIYO YUDEN LMK212BJ225MG-T or equivalent
External decoupling capacitors are recommended on all power pins.
Analog inputs must be driven from an operational amplifier that does not degrade the ADC performance.
Figure 4-9. ADC Pin Connections With Internal Reference
Copyright © 2007–2012, Texas Instruments Incorporated
Peripherals
79
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