Texas Instruments PGA309EVM-USB - Manual (Page 5)

USB DAQ
Platform
PGA309
Test Board
EVM
Power
PGA309
V Supply
Switched 5.0V Power
DUT
One-Wire Interface
25-Pin
Male DSUB Signals
From USB DAQ Platform
25-Pin
Female DSUB Signals
From USB DAQ Platform
I C
Interface
2
4mA to 20mA
I/V Converter
Sensor
Connection
Sensor
Emulator
www.ti.com System Setup
2 System Setup
Figure 2 shows the system setup for the PGA309EVM. The PC runs software that communicates with the
USB-DAQ-Platform. The USB-DAQ-Platform generates the digital signals used to communicate with the
PGA309_Test_Board. Connectors on the PGA309_Test_Board allow for connection to the bridge sensor.
Figure 2. PGA309EVM-USB Hardware Setup
2.1 Theory of Operation for PGA309_Test_Board Hardware
Figure 3 shows the block diagram of the PGA309_Test_Board. The PGA309_Test_Board provides
connections to the I 2 C™, one-wire, analog-to-digital converters (ADCs) and digital-to-analog converters
(DACs) on the USB-DAQ-Platform. It also provides connection points for external connection of the bridge
sensor. The PGA309_Test_Board has circuitry to convert the PGA309 voltage output to 4mA to 20mA
current.
Figure 3. PGA309_Test_Board Block Diagram
5 SBOU084 – February 2010 PGA309EVM-USB
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