Texas Instruments PGA309EVM-USB System Setup, Theory of Operation for PGA309TestBoard Hardware

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2System 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.

EVM

POWER

USB￿DAQ

PLATFORM

PGA309

TEST￿BOARD

Figure 2. PGA309EVM-USB Hardware Setup

2.1Theory 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 I2C™ , 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.

25-Pin Male￿DSUB￿Signals From￿USB￿DAQ￿Platform

VDUT Supply
Switched￿5.0V￿Power
I2C
Interface
One-Wire￿Interface	PGA309

4mA￿to￿20mA I/V￿Converter

Sensor

Emulator

25-Pin Female￿DSUB￿Signals From￿USB￿DAQ￿Platform

Sensor

Connection

Figure 3. PGA309_Test_Board Block Diagram

SBOU084 –February 2010	PGA309EVM-USB	5
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