SBAU409A September   2022  – November 2022

 

  1.   Abstract
  2.   Trademarks
  3. 1Overview
    1. 1.1 ADS9218EVM-PDK Features
    2. 1.2 ADS9218EVM Features
  4. 2Analog Interface
    1. 2.1 ADS9218 Device Connections
    2. 2.2 ADC Differential Input Fully Differential Amplifier (FDA)
    3. 2.3 Common Mode Amplifier Drive
    4. 2.4 Voltage Reference
  5. 3Digital Interface
    1. 3.1 Clock Connection
  6. 4Power Supplies
  7. 5ADS9218EVM Software Installation
  8. 6EVM Operation
    1. 6.1 USB Driver Installation
    2. 6.2 Connecting the Hardware and Starting Software
    3. 6.3 Optional Connections to the EVM
    4. 6.4 Initial Required Setup on the Config Tab
    5. 6.5 Initial Required Setup on the Capture Tab
  9. 7Bill of Materials, Schematics, and Layout
    1. 7.1 Bill of Materials (BOM)
    2. 7.2 Schematics
    3. 7.3 Layout
  10. 8Revision History

2.3 Common Mode Amplifier Drive

The ADS9218 has a common-mode output pin (VCMOUT). The common-mode signal must be buffered to drive the THS4552 common-mode input pin. Figure 2-3 shows an example of the buffer circuit. R35 bypasses the amplifier and is not populated. When R35 is populated, U8 is unpopulated so that the ADC VCMOUT pin directly drives the FDA VCM input.

Figure 2-3 Common-Mode Amplifier Drive