ADS8284
SLAS628–MARCH 2009................................................................................................................................................................................................... www.ti.com
APPLICATION INFORMATION
As discussed before, the ADS8284 is 18-bit analog SoC that includes various blocks like a multiplexer, ADC
driver, internal reference, internal reference buffer, buffered reference output, and Ref/2 output on-board. The
following diagram shows the recommended analog and digital interfacing of the ADS8284.
APPLICATION DIAGRAM
From Host
AUTO,
C1, C2,
C3
MXCLK
+VA
VCC
CH0P
CH1P
CH2P
VOLTAGE
CLAMP
-
+/-4 V,
diff-
Signals
with 2 V
common
mode,
Source
res
< = 50 W
OPA-1
BUSY
10 Ω
+VA
CH3P
+
VEE
VCC
DB0 - DB17
18 bit 1 MSPS
ADC
LOGIC
-
I/O
+VA
CH0M
CH1M
CH2M
BUS18/16
BYTE
RD
To Host
-
BUFFER
OPA-2
VEE
CS
10Ω
CH3M
+
CONVST
INP
1nF
INM
+VA
VCC
VCM-O:
VREF/2
Ref/2 for common
mode of diff-
amplifier in signal
path
REFIN
VCC
BUF-REF:
For use on
application board
+VA
REFOUT
0.1
mF
INTERNAL - REF
1mF
PD-RBUF : Connect this
pin to VCC to power
down ‘Ref-Buffer’
REFM
Figure 70. Analog and Digital Interface Diagram
As shown in Figure 70, the ADS8284 accepts unipolar differential analog inputs in the range of ±Vref with a
common-mode voltage of Vref/2 (0 to Vref at positive input and Vref to 0 at negative input). An application may
require the interfacing of true bipolar input signals. Figure 71 shows the conversion of bipolar input signals to
unipolar differential signals.
26
Submit Documentation Feedback
Copyright © 2009, Texas Instruments Incorporated
Product Folder Link(s) :ADS8284
TI [ TEXAS INSTRUMENTS ]
