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7 Using the EVM
Using the EVM
Table 6. Power Supply Test Points (continued)
Test Point Signal Description
TP14 +VA Apply +12 Vdc. Positive supply for amplifier
TP15 –VA Apply –12 Vdc. Negative supply for amplifier
2. Use the power connector J5 and derive the voltages elsewhere. The pinout for this connector is
shown in Table 7
Table 7. Power Connector, J1, Pinout
Signal Power Connector – J5 Signal
+VA(+12V) 1 2 –VA(–12V)
+5VA 3 4 N/C
N/C 5 6 AGND
N/C 7 8 N/C
N/C 9 10 +5VD
The ADS8323EVM serves three functions as a reference design, a prototype board, and as a test platform
for the software engineer to develop code.
As a reference design, the ADS8323EVM contains the essential circuitry to showcase the analog-to-digital
converter. This essential circuitry includes the input amplifier and digital buffers. The EVM analog input
circuit is optimized for 100-kHz sine wave; therefore, users may need to adjust the resistor and capacitor
values of the A/D input RC circuit. In ac-type applications where signal distortion is a concern,
polypropylene or low-cost SMT C0G ceramic capacitors should be used in the signal path. In applications
where the input is multiplexed, the A/D input resistor and capacitor may need to be adjusted or possibly
removed altogether.
As a prototype board, the buffer circuit consists of a standard 8-pin SOIC amplifier and resistor pads to
adjust to various inverting and noninverting configurations. The EVM comes installed with a dual-supply
amplifier, which allows the user to take advantage of the full input voltage range of the converter. For
applications that require signal supply operation and smaller input voltage range, the THS4031 can be
replaced with the single-supply amplifier like OPA300 or OPA355. Be sure to short the negative supply pin
to ground in that case. Positive supply voltage can be applied via test point TP14 or connector J5, pin 1.
As a software test platform, connectors J1, J2, and J3 plug into the parallel interface connectors of the
5-6K Interface Board. The 5-6K Interface Board sits on the 'C5000 and 'C6000 digital signal processor
starter kit (DSK). The ADS8323EVM is then mapped into the processor’s memory space. This board also
provides an area for signal conditioning. This area can be used to install application circuit(s) for
digitalization by the ADS8323 analog-to-digital converter. See the 5-6K Interface Board User’s Guide
(SLAU104 ) for more information.
For the software engineer, the ADS8323EVM provides a simple platform for interfacing to the converter.
The EVM provides standard 0.1-in. headers and sockets to wire into prototype boards. The user needs
only to provide three address lines (A2, A1, and A0) and address valid line ( DC_CS) , and clock to
connector J2. To choose which address combinations will generate RD and CONVST, set jumpers as
shown in Table 2 . If address decoding is not required, the EVM provides direct access to converter data
bus via J3 and control via J4.
ADS8323EVM 6 SLAU087A – July 2002 – Revised December 2004