SLOU582 September   2024

 

  1.   1
  2.   Description
  3.   Features
  4.   Applications
  5.   5
  6. 1Evaluation Module Overview
    1. 1.1 Introduction
    2. 1.2 Kit Contents
    3. 1.3 Specification
    4. 1.4 Device Information
  7. 2Hardware
    1. 2.1 Pin Specifications
    2. 2.2 Power Requirements
    3. 2.3 Input Connectors
    4. 2.4 Output Connectors
    5. 2.5 Onboard Bandpass Filter
    6. 2.6 LNA and AFE Enable/Disable
    7. 2.7 Offset Cancellation And Log In- Cap Capacitor Value Selection
  8. 3Hardware Design Files
    1. 3.1 Schematics
    2. 3.2 PCB Layouts
    3. 3.3 Bill of Materials (BOM)
  9. 4Additional Information
    1. 4.1 Trademarks

2.7 Offset Cancellation And Log In- Cap Capacitor Value Selection

The offset cancellation cap (C8) needs to be selected based on the input frequency to the system. To get the best performance, use the value as recommended in the table below.

Frequency (kHz) Offset_cap (C8) Value (nF)
40 150
65 100
85 68
180 33
255 33
310 22
370 15
850 6.8
Note: Offset cap must never be less than 1nF.

Also, TI recommends to match the impedance of LOG IN+ and LOG IN- for the frequencies equal to or less than the supply filter cutoff frequency formed by R1 and decaps (C1||C2||C3).