Texas Instruments PGA309EVM-USB guide

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System Setup

Figure 6 shows the output section of the PGA309EVM_Test_Board. There are two output options: voltage output and current output. The voltage output option is selected by placing JMP9 in the NC position. The current output option is selected by moving JMP9 to the VOUT to XTR position.

Figure 6. PGA309_Test_Board Schematic: Output Circuitry

In voltage output mode, C10 = 10nF is connected to the PGA309 output. This capacitor is used for radio frequency interference (RFI) and electromagnetic interference (EMI) immunity. This component should be included in your design, if possible.

In current output mode, the PGA309 output is connected to a voltage-to-current (V-I) converter (XTR117). The sum of R6 and R8 convert the output voltage from the PGA309 to an input current for the XTR117. R7 can be used to create an input offset current using the reference. The total input current is IIN = VOUT / (R6 + R8) + VREF/R7. The output current is equal to the input current times the current gain (x 100).

D4 is used for reverse polarity protection. D3 is used for over-voltage transient protection. D3 was selected for low leakage. Leakage on D3 directly contributes to error. C11 is a decoupling capacitor and is required for proper operation. The external transistor, Q1, conducts the majority of the full-scale output current. Power dissipation in this transistor can approach 0.8W with high loop voltage (40V) and 20mA output current.

SBOU084 –February 2010	PGA309EVM-USB	9
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PGA309EVM-USB specifications

The Texas Instruments PGA309EVM-USB is an Evaluation Module designed specifically for the PGA309 Precision Analog Front End (AFE) family. This versatile and powerful device serves various applications in the realm of sensor signal conditioning, particularly for pressure sensors, temperature sensors, and other analog sensors requiring high precision.

One of the main features of the PGA309EVM-USB is its high-performance PGA309 device, which incorporates a programmable gain amplifier (PGA) allowing for flexible signal amplification. The PGA309 has a gain range from 1 to 128, enabling it to adapt to a wide array of sensor types and output levels. This flexibility is crucial for achieving optimal performance in diverse applications.

The module also leverages advanced analog and digital processing technologies, which enhance its capabilities. It integrates an onboard microcontroller, allowing users to easily configure settings, execute control algorithms, and manage data acquisition. The built-in USB interface simplifies the communication with a PC, making it straightforward to control the EVM through intuitive software provided by Texas Instruments.

Another significant characteristic of the PGA309EVM-USB is its highly accurate signal conditioning features, such as offset and gain calibration, which ensure minimized errors and improved measurement reliability. The device supports a variety of digital output configurations, including I2C and SPI, to allow easy integration into different system architectures.

In addition to its robust signal processing core, the PGA309EVM-USB is designed with user-friendly interfaces, making it suitable for both experienced engineers and those new to sensor design. The comprehensive software toolkit offers a graphical user interface (GUI) that enables real-time monitoring and adjustment of parameters, ensuring users can optimize their applications.

Furthermore, the device is designed for functionality in harsh environments, incorporating features to withstand temperature variations and electrical noise. This reliability adds value for applications in industrial automation, automotive systems, and medical devices.

In summary, the Texas Instruments PGA309EVM-USB stands out as a powerful tool for engineers looking to design and prototype high-precision sensor signal conditioning applications. With its programmable gain amplifier, advanced processing capabilities, and user-friendly interfaces, it represents a significant advancement in the field of analog signal processing, allowing for greater flexibility and accuracy in diverse applications.