Datasheet
PRODUCT OVERVIEW
ANALOG OUTPUTS
VOLTAGE REFERENCE VCOM
PCM1690
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.............................................................................................................................................. SBAS448A – OCTOBER 2008 – REVISED JANUARY 2009
The PCM1690 is a high-performance, multi-channel DAC targeted for consumer audio applications such as
Blu-ray DVD players and HD DVD players, as well as home multi-channel audio applications (such as home
theaters and A/V receivers). The PCM1690 consists of an eight-channel DAC. The DAC output type is fixed with
a differential configuration. The PCM1690 supports 16-/20-/24-/32-bit linear PCM input data in I
2
S- and
left-justified audio formats, and 24-bit linear PCM input data in right-justified, DSP, and TDM formats for various
sampling frequencies from 8 kHz to 192 kHz. The TDM format is useful for saving bus line interface numbers for
multi-channel audio data communication between the DAC and a digital audio processor. The PCM1690 offers
three modes for device control: two-wire I
2
C software, three-wire SPI software, and hardware modes.
The PCM1690 includes eight DACs, each with individual pairs of differential voltage outputs pins. The full-scale
output voltage is (1.6 × VCC1) V
PP
at the differential output mode. A dc-coupled load is allowed in addition to an
ac-coupled load if the load resistance conforms to the specification. These balanced outputs are each capable of
driving 0.8 VCC1 (4 V
PP
) typical into a 5-k Ω , ac-coupled or 15-k Ω , dc-coupled load with VCC1 = +5 V. The
internal output amplifiers for VOUT1 through VOUT8 are biased to the dc common voltage, equal to (0.5 ×
VCC1).
The output amplifiers include an RC continuous-time filter that helps to reduce the out-of-band noise energy
present at the DAC outputs as a result of the noise shaping characteristics of the PCM1690 delta-sigma ( Δ Σ )
DACs. The frequency response of this filter is shown in the Analog Filter Characteristic (Figure 10 ) of the Typical
Characteristics . By itself, this filter is not enough to attenuate the out-of-band noise to an acceptable level for
most applications. An external low-pass filter is required to provide sufficient out-of-band noise rejection. Further
discussion of DAC post-filter circuits is provided in the Application Information section.
Table 1. Pin Assignments in Differential Output Mode
DIGITAL INPUT CHANNEL DIFFERENTIAL OUTPUT
1 (DAC1) VOUT1+, VOUT1 –
DIN1
2 (DAC2) VOUT2+, VOUT2 –
3 (DAC3) VOUT3+, VOUT3 –
DIN2
4 (DAC4) VOUT4+, VOUT4 –
5 (DAC5) VOUT5+, VOUT5 –
DIN3
6 (DAC6) VOUT6+, VOUT6 –
7 (DAC7) VOUT7+, VOUT7 –
DIN4
8 (DAC8) VOUT8+, VOUT8 –
The PCM1690 includes a pin for the common-mode voltage output, VCOM. This pin should be connected to the
analog ground via a decoupling capacitor. This pin can also be used to bias external high-impedance circuits, if
they are required.
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