SBAA591 December   2023 REF54

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2Flicker Noise Measurement Method
  6. 30.1 Hz to 10 Hz Band Pass Filter Design for Reference Noise Measurement
    1. 3.1 Filter Schematic
    2. 3.2 TINA - TI simulations
    3. 3.3 Component Selection
  7. 4Measurement Setup
    1. 4.1 REF54250CDR Noise Measurement Setup
  8. 5Filter Board Design
    1. 5.1 Schematic
      1. 5.1.1 Schematics Images
    2. 5.2 Layout
    3. 5.3 Bill of Materials
  9. 6References

4 Measurement Setup

The filter board is kept in a metal box to avoid any EMI. All the cables that carry VREF or noise are shielded cables.

GUID-20230809-SS0I-Z4P2-RCZK-VC9MJFCDRNSB-low.svg Figure 4-1 Metal Box for Noise Filter to Avoid External Interference

The output was terminated with 50 Ω, and we kept the setup on for 12 hours to measure the noise floor. The typical noise floor of the board is 40 nV pk-pk which introduces <1.5 % error in the lowest noise measurement.

GUID-20230808-SS0I-9FZ1-PRPR-QJW33F533DPM-low.png Figure 4-2 Typical Noise Floor of the Filter Board