Datasheet

PCM3070
www.ti.com SLAS724 – FEBRUARY 2011
• 2 programmable gain amplifiers (PGA) with a range of 0 to +47.5dB
• 2 mixer amplifiers for analog bypass
• 2 analog bypass channels
• Fine gain adjust of digital channels with 0.1 dB step size
• Digital volume control with a range of -12 to +20dB
• Mute function
• Automatic gain control (AGC)
In addition to the standard set of ADC features the PCM3070 also offers the following special functions:
• Channel-to-channel phase adjustment
• Fast charge of ac-coupling capacitors
• Anti thump
• Adaptive filter mode
ADC Processing
The PCM3070 ADC channel includes a built-in digital decimation filter to process the oversampled data from the
sigma-delta modulator to generate digital data at Nyquist sampling rate with high dynamic range. The decimation
filter can be chosen from three different types, depending on the required frequency response, group delay and
sampling rate.
ADC Processing Blocks
The PCM3070 offers a range of processing blocks which implement various signal processing capabilities along
with decimation filtering. These processing blocks give users the choice of how much and what type of signal
processing they may use and which decimation filter is applied.
Table 9 gives an overview of the available processing blocks of the ADC channel and their properties.
The signal processing blocks available are:
• First-order IIR
• Scalable number of biquad filters
• Variable-tap FIR filter
• AGC
The processing blocks are tuned for common cases and can achieve high anti-alias filtering or low-group delay in
combination with various signal processing effects such as audio effects and frequency shaping. The available
first order IIR, BiQuad and FIR filters have fully user-programmable coefficients. The Resource Class Column
(RC) gives an approximate indication of power consumption.
Table 9. ADC Processing Blocks
Processing Channel Decimation 1st Order Number FIR Required Resource
Blocks AOSR Value
Filter IIR Available BiQuads Class
PRB_R1
(1)
Stereo A Yes 0 No 128,64 6
PRB_R2 Stereo A Yes 5 No 128,64 8
PRB_R3 Stereo A Yes 0 25-Tap 128,64 8
PRB_R4 Right A Yes 0 No 128,64 3
PRB_R5 Right A Yes 5 No 128,64 4
PRB_R6 Right A Yes 0 25-Tap 128,64 4
PRB_R7 Stereo B Yes 0 No 64 3
PRB_R8 Stereo B Yes 3 No 64 4
PRB_R9 Stereo B Yes 0 20-Tap 64 4
PRB_R10 Right B Yes 0 No 64 2
PRB_R11 Right B Yes 3 No 64 2
(1) Default
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Product Folder Link(s): PCM3070