SBAA377B April   2022  – January 2024 PCM3120-Q1 , PCM5120-Q1 , PCM6120-Q1 , TLV320ADC3120 , TLV320ADC3140 , TLV320ADC5120 , TLV320ADC5140 , TLV320ADC6120 , TLV320ADC6140

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2Inherent Anti-Aliasing in TLV320ADCx140/TLV320ADCx120/PCMx120-Q1/PCMx140-Q1
  6. 3Flexible Digital Filters
    1. 3.1 Multi-Stage Decimation Filters
      1. 3.1.1 Linear Phase
      2. 3.1.2 Low-Latency Filters
      3. 3.1.3 Ultra-Low-Latency Filters
    2. 3.2 Programmable Biquad Filters
  7. 4References
  8. 5Revision History

3.1 Multi-Stage Decimation Filters

TLV320ADCx140/TLV320ADCx120/PCMx120-Q1/PCMx140-Q1 devices offer three distinct sets of decimation filters: Linear Phase, Low-Latency, and Ultra-Low-Latency. Table 3-1 shows the comparative performance of the three decimation filter options. The linear phase filters provide zero group delay deviation. The low-latency and ultra-low-latency filters offer lower group delay and higher attenuation but with higher group delay deviation than the linear phase filters. Refer to Linear Phase Filters, Low-Latency Filters, and Ultra-Low-Latency Filters sections of the TLV320ADC5140 Quad-Channel, 768-kHz, Burr-Brown Audio ADC Data Sheet, TLV320ADC6140 Quad-Channel, 768-kHz, Burr-Brown Audio ADC Data Sheet, and TLV320ADC3140 Quad-Channel, 768-kHz, Burr-Brown Audio ADC Data Sheet for exact filter responses for supported sample rates.

Table 3-1 Decimation Filter Characteristics
LINEAR PHASELOW LATENCYULTRA-LOW LATENCY
GROUP DELAY (IN NUMBER OF SAMPLES)10–205–73–5
GROUP DELAY DEVIATION (IN NUMBER OF SAMPLES)0< 0.1< 0.5
OUT-OF-BAND ATTENUATION (dB)> 72> 85> 85