SBOU286A October   2022  – December 2022 INA350 , INA351

 

  1.   DDF Instrumentation Amplifier Evaluation Module
  2.   Trademarks
  3. 1Overview
    1. 1.1 Features
    2. 1.2 Instrumentation Amplifier Pinout
    3. 1.3 Compatible Devices
  4. 2PCB Layout
  5. 3Schematic
  6. 4EVM Components
    1. 4.1 Power
    2. 4.2 Inputs
      1. 4.2.1 Input Filtering
    3. 4.3 Output
      1. 4.3.1 Output Filtering
    4. 4.4 Reference
    5. 4.5 Other Passives
    6. 4.6 Miscellaneous
  7. 5Quick Start
    1. 5.1 Dual-Supply Configuration
    2. 5.2 Single-Supply Configuration
      1. 5.2.1 Direct-Reference Connection
      2. 5.2.2 Buffered-Reference Voltage Connection
  8. 6Bill of Materials
  9. 7Revision History

5.2.2 Buffered-Reference Voltage Connection

A buffered-reference configuration is useful when the source impedance is high (for example, a voltage divider). Buffering a high-impedance source with an operational amplifier provides a low-impedance source and preserves common-mode rejection. Figure 5-3 shows an example of how to set up the EVM for single-supply operation with a buffered-reference voltage connection. Depending on the application, desirable single-supply buffer operational amplifiers include the TLV9001, TLV9041, TLV9051, and TLV9061.

Figure 5-3 Single-Supply Configuration, Buffered REF Connection

The following connections were made:

  1. +VS to V+ test point
  2. V+OPA to OAV+ test point
  3. GND to V– and OAV– test points
  4. VREF to OAVIN+ test point
  5. Ensure that R17 is not populated
  6. Populate R12, R15, and R16 with a 0-Ω resistor
  7. Populate C10, C11, C15, and C20 with appropriate decoupling capacitors for buffer amplifier
  8. Differential input signal to IN– and IN+ test points
  9. Observe output at OUT test point

Note:

1. C9 and C10 are prepopulated with 0.1-µF power-supply decoupling capacitors. It is not required to remove C9 for proper single-supply operation. Refer to the device data sheet for additional power-supply decoupling information (Table 1-1).

2. A valid input common mode must be present on both inputs of the IA for proper operation.