SBOU273A February   2022  – November 2022 INA851

 

  1.   INA851 Evaluation Module
  2.   Trademarks
  3. 1Overview
    1. 1.1 Related Documentation
    2. 1.2 Electrostatic Discharge Caution
    3. 1.3 Hot Surface Warning
  4. 2EVM Circuit Description
  5. 3Jumper Settings
  6. 4Power-Supply Connections
  7. 5Input and Output Connections
  8. 6Modifications
  9. 7Schematic, PCB Layout, and Bill of Materials
    1. 7.1 Schematic
    2. 7.2 PCB Layout
    3. 7.3 Bill of Materials
  10. 8Revision History

2 EVM Circuit Description

This EVM provides access to the features and measures the performance of the INA851. By default, the INA851EVM instrumentation amplifier is configured to a gain of 1 V/V. The evaluation board provides optional footprints for gain resistors RG1 and RG2 to modify the input-stage instrumentation-amplifier gain. Optional footprints R5 and R9 can be populated with 0-Ω jumpers to set the output stage gain to 0.2 V/V.

The INA851 incorporates features that simplify interfacing to a fully-differential ADC. The VOCM connector sets the output common-mode voltage. If the VOCM connector is not driven, the output common-mode voltage defaults to the INA851 midsupply value. Clamp pins are provided to limit the INA851 output voltage level, which can be applied to the ADC inputs. The output clamp pins, VCLAMP+ and VCLAMP–, are accessible using connector J9. Selectable jumpers J11 and J12 set the output clamp voltage level to the INA851 supplies (default), or to external voltages using connector J9.

Revision A of the INA851EVM allows access to the FDA_IN– and FDA_IN+ pins with optional capacitors C7 and C18. These capacitors are in parallel with the INA851 output stage internal feedback resistors to implement noise filtering. A simplified block diagram of the INA851EVM is displayed in Figure 2-1. For a full schematic of the INA851EVM, see Figure 7-1.

Figure 2-1 INA851EVM Simplified Schematic