AD1853 Analog Devices, AD1853 Datasheet - Page 10

• Manufacturer Part Number: AD1853
• Description: Stereo/ 24-Bit/ 192 kHz/ Multibit DAC
• Manufacturer: Analog Devices

Mute
The AD1853 offers two methods of muting the analog output.
By asserting the MUTE (Pin 23) signal HI, both the left and
right channel are muted. As an alternative, the user can assert
the mute bit in the serial control register (Bit 6) HI. The AD1853
has been designed to minimize pops and clicks when muting
and unmuting the device by automatically “ramping” the gain
up or down. When the device is unmuted, the volume returns to
the value set in the volume register.
Analog Attenuation
The AD1853 also offers the choice of using IREF (Pin 10) to
attenuate by up to 50 dB in the analog domain. This feature can
be used as an analog volume control. It is also a convenient
place to add a compressor/limiter gain control signal.
Output Drive, Buffering and Loading
The AD1853 analog output stage is able to drive a 1 kΩ (in
series with 2 nF) load. The analog outputs are usually ac
coupled with a 10 µF capacitor.
AD1853
Figures 9–14 show the calculated frequency response of the
digital interpolation filters. Figures 15–27 show the performance
of the AD1853 as measured by an Audio Precision System 2
Cascade. For the wideband plots, the noise floor shown in the
Control Register
The following table shows the functions of the control register. The control register is addressed by having a “01” in the bottom 2 bits
of the 16-bit SPI word. The top 14 bits are then used for the control register.
Bit 11
INT2× Mode
OR’d with Pin.
Default = 0
Figure 9. Passband Response 8 × Mode, 48 kHz Sample
Rate
–0.0002
–0.0004
–0.0006
–0.0008
0.0008
0.0006
0.0004
0.0002
–0.001
0.001
0
0
2
Bit 10
INT4× Mode
OR’d with Pin.
Default = 0
4
6
FREQUENCY – kHz
8
10
Bit 9:8
Number of
Bits in Right-
Justified Serial
Mode.
0:0 = 24
0:1 = 20
1:0 = 16
Default = 0:0
12
14
16
18
20
Bit 7
Soft Reset.
Default = 0
–10–
plots is higher than the actual noise floor of the AD1853. This is
caused by the higher noise floor of the “High Bandwidth” ADC
used in the Audio Precision measurement system. The two-tone
test shown in Figure 18 is per the SMPTE standard for measur-
ing Intermodulation Distortion.
De-Emphasis
The AD1853 has a built-in de-emphasis filter that can be used
to decode CDs that have been encoded with the standard
“Redbook” 50 µs/15 µs emphasis response curve. Three curves
are available; one each for 32 kHz, 44.1 kHz and 48 kHz sam-
pling rates. The external “DEEMP” pin (Pin 9) turns on the
44.1 kHz de-emphasis filter. The other filters may be selected
by writing to control Bits 2 and 3 in the control register. If the
SPI port is used to control the de-emphasis filter, the external
DEEMP pin should be tied LO.
Control Signals
The IDPM0 and IDPM1 control inputs are normally con-
nected HI or LO to establish the operating state of the AD1853.
They can be changed dynamically (and asynchronously to
LRCLK and the master clock), but it is possible that a click
or pop sound may result during the transition from one serial
mode to another. If possible, the AD1853 should be placed in
mute before such a change is made.
Figure 10. Complete Response, 8 × Mode, 48 kHz
Sample Rate
Bit 6
Soft Mute OR’d Serial Mode OR’d
with Pin.
Default = 0
–100
–120
–140
–160
–20
–40
–60
–80
0
0
50
Bit 5:4
with Mode Pins.
IDPMI:IDPM0
0:0 Right-Justified
0:1 I
1:0 Left-Justified
1:1 DSP Mode
Default = 0:0
100
2
S
FREQUENCY – kHz
150
200
250
Bit 3:2
De-Emphasis Filter
Select.
0:0 No Filter
0:1 44.1 kHz Filter
1:0 32 kHz Filter
1:1 48 kHz Filter
Default = 0.0
300
350
REV. A