PCM3793RHB BURR-BROWN [Burr-Brown Corporation], PCM3793RHB Datasheet - Page 17

• Manufacturer Part Number: PCM3793RHB
• Description: 16-Bit, Low-Power Stereo Audio CODEC With Microphone Bias, Headphone, and Digital Speaker Amplifier
• Manufacturer: BURR-BROWN [Burr-Brown Corporation]

Speaker Output (Class-D, PCM3793)
The SPOLP, SPOLN and SPORP, SPORN pins are stereo or mono speaker differential outputs (BTL) with a
maximum of 700 mWrms (V
maximum battery life and minimum heat, eliminates the LC low-pass filter, and includes analog volume
amplification for each output from 6 dB to –70 dB with 0.5-, 1-, 2- or 4-dB steps, which can be set by register 66,
67 (SLV[5:0], SLR[5:0]). Spectrum spreading technology and selectable switching frequency to reduce EMI
noise is controlled by register 71 (DFQ[2:0], SPS[1:0] and SPSE). The speaker amplifiers have a thermal
shutdown circuit which detects when the device temperature reaches approximately 150 C; then the speaker
amplifier is powered down.
Analog Mixing and Bypass
Mixing amplifiers (MXL, MXR) mix gain-controlled analog inputs from the AIN pins which have bypassed ADC
and DAC and direct the mixed signal to the headphone or speaker outputs. Analog mixing is controlled by
register 87 (AD2S, AIR[1:0], AIL[1:0]), register 88 (MXR[2:0], MXL[2:0]), and register 89 (GMR[2:0], GML[2:0]).
The analog mixing functions are suitable for FM radio, headset, and another analog sources without an ADC.
Microphone Bias
The MICB pin is the microphone bias source for an external microphone and can provide 2 mA (typical) bias
current.
Automatic Level Control (ALC) for Recording
The sound for microphone recording should be expanded to a suitable level without saturation. The digitally
controlled automatic level control (ALC) provides automatic expansion for small input signals and compression
for large input signals while recording. The expansion level, compression level, attack time, and recovery time
can be selected by register 83. The register 83 description explains the details of these settings.
3-D Sound
A 3-D sound effect is provided by mixing L-channel and R-channel data with band pass filter that can be
controlled two parameters, mixing ratio and band pass filter characteristic by register 95 (3DP[3:0], 3FLO). The
3-D sound effect can be applied to the DAC digital input or ADC digital output, as selected by register 95
(SDAS).
Three-Band Tone Control
Tone control has bass, midrange, and treble controls that can be adjusted from 12 dB to –12 dB in 1-dB steps
by registers 92 to 94 (LGA[4:0], MGA[4:0] and HGA[4:0]). Register 92 (LPAE) attenuates the digital input signal
automatically to prevent clipping of the output signal at settings above 0 dB for bass control. LPAE has no effect
on midrange and treble controls.
High-Pass Filter and Notch Filter
The high-pass filter eliminates the dc offset of the ADC analog signal and can be set for a cutoff frequency of 4
Hz or 240 Hz at of 48-kHz sampling frequency by register 81 (HPF[1:0]). A register 95 (SDAS) selection applies
the filter to either the DAC digital input or the ADC digital output.
Notch filters are provided to remove noise of a particular frequency, such as CCD noise, motor noise, or other
mechanical noise in a particualr application. The PCM3793/94 has two notch filters for which the center
frequency and frequency bandwidth can be programmed by registers 96 to 104. A register 95 (SDAS) selection
applies the filter to either the DAC digital input or the ADC digital output.
Digital Monaural Mixing
Register 96 (MXEN) enables or disables the internal mixing of stereo digital data to monaural digital data.
Zero-Cross Detection
Zero-cross detection minimizes audible zipper noise while changing analog volume and digital attenuation. This
function can be applied to digital input or digital output by register 86 (ZCRS).
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= 3.6 V, volume = 6 dB) into an 8-
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SLES193A – AUGUST 2006 – REVISED SEPTEMBER 2006
load. The digital speaker amplifier offers
PCM3793
PCM3794
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