Figure 6-34 DAC Signal-Chain Processing Flowchart

The DAC signal chain offers a highly flexible low noise playback path for low noise and high-fidelity audio applications. This low-noise and low-distortion, multibit, delta-sigma DAC enables the TAC5311-Q1 to achieve 120dB dynamic range in a very low power. Moreover, the DAC architecture has inherent antialias filtering with a high rejection of out-of-band frequency noise around multiple modulator frequency components. Therefore, the device prevents noise from aliasing into the audio band. Further on in the signal chain, an integrated, high-performance multistage digital interpolation filter sharply cuts off any out-of-band frequency noise with high stop-band attenuation.

The signal chain also consists of various highly programmable digital processing blocks such as biquad filters, phase calibration, gain calibration, high-pass filter, digital summer or mixer, synchronous sample rate converter, distortion limiter, thermal foldback, brownout prevention, and volume control. The details of these processing blocks are discussed further in this section. The device also supports up to four channel single-ended output modes and an analog bypass option from ADC input to DAC output.

The output channels for playback can be enabled or disabled by using the CH_EN (P0_R118) register, and the input channels for the audio serial interface can be enabled or disabled by using the PASI_RX_CHx_CFG or SASI_RX_CHx_CFG bits. The device supports simultaneous power-up and power-down of all active channels for simultaneous playback. However, based on the application needs, if some channels must be powered-up or powered-down dynamically when the other channel playback is on, then that use case is supported by setting the DYN_PUPD_CFG register.

The device supports multiple data mixing options where up to 8 Input Channels from Main ASI, 2 Input Channels from Aux ASI, ADC loopback data, and tone generator can be mixed with flexible gain options for each path before playback on DAC output. By default, these mixers are disabled and channels are configured for only one channel data. Mixers can be configured by setting ASI_DIN_Mixers on Page 17.

The device supports an output signal bandwidth up to 100kHz, which allows the high-frequency non-audio signal to be played by using a 216kHz (or higher) sample rate. Wide band mode can be enabled or disabled by using the DAC_CHx_BW_Mode bit.

For sample rates of 48kHz or lower, the device supports all features and various programmable processing blocks. However, for sample rates higher than 48kHz, there are limitations in the number of simultaneous channel recording and playback supported and the number of biquad filters and such. See the TAC5212 Sampling Rates and Programmable Processing Blocks Supported application report for further details.