SBASA14 May 2020 PCMD3180
PRODUCTION DATA.
The PCMD3180 signal chain is comprised of high-performance, low-power and highly flexible and programmable digital processing blocks. The high performance and flexibility combined with a compact package makes the PCMD3180 optimized for a wide variety of end-equipments and applications that require multichannel audio capture. Figure 32 shows a conceptual block diagram that highlights the various building blocks used in the signal chain, and how the blocks interact in the signal chain.
The device supports up to eight digital PDM microphone recording channels for simultaneous operation. The signal chain consists of various highly programmable digital processing blocks such as phase calibration, gain calibration, high-pass filter, digital summer or mixer, biquad filters, and volume control. The details on these processing blocks are discussed further in this section. Channels 1 to 4 in the signal chain block diagram of Figure 32 are as described in this section, however, channels 5 to 8 do not support the digital summer or mixer option.
The desired input channels for recording can be enabled or disabled by using the IN_CH_EN (P0_R115) register, and the output channels for the audio serial interface can be enabled or disabled by using the ASI_OUT_EN (P0_R116) register. In general, the device supports simultaneous power-up and power-down of all active channels for simultaneous recording. However, based on the application needs, if some channels must be powered-up or powered-down dynamically when the other channel recording is on, then that use case is supported by setting the DYN_CH_PUPD_EN, P0_R117_D4 register bit to 1'b1 but do not power-down channel 1 in this mode of operation.
The device supports an input signal bandwidth up to 80 kHz, which allows the high-frequency non-audio signal to be recorded by using a 176.4-kHz (or higher) sample rate.
For output sample rates of 48 kHz or lower, the device supports all features for 8-channel recording and various programmable processing blocks. However, for output sample rates higher than 48 kHz, there are limitations in the number of simultaneous channel recordings supported and the number of biquad filters and such. See the TLV320ADCx140 Sampling Rates and Programmable Processing Blocks Supported application report for further details.