AD1953YST Analog Devices Inc, AD1953YST Datasheet - Page 23

• Manufacturer Part Number: AD1953YST
• Description: IC DAC AUDIO 3CH 26BIT 48-LQFP
• Manufacturer: Analog Devices Inc
• Series: SigmaDSP®r

Specifications of AD1953YST

• Rohs Status: RoHS non-compliant
• Number Of Bits: 26
• Data Interface: Serial
• Number Of Converters: 3
• Voltage Supply Source: Analog and Digital
• Power Dissipation (max): 540mW
• Operating Temperature: -40°C ~ 105°C
• Mounting Type: Surface Mount
• Package / Case: 48-LQFP
• For Use With: EVAL-AD1953EBZ - BOARD EVAL FOR AD1953 3CH 24BIT
• Settling Time: -

Volume Registers
The AD1953 contains eight 22-bit volume registers, one each
for the left, right, and subwoofer channels and an additional five
registers to be used by custom programs used in multichannel
applications. These registers are special because when the volume
is changed from an initial value to a new value, a linear ramp is
used to interpolate between the two values. This feature prevents
audible clicks and pops when changing volume. The ramp is
set so that it takes 512 audio frames to decrement from a volume of
1.0 (default) down to 0 (muted). The volume registers are for-
matted in 2.20 twos complement, meaning that 010000000
0000000000000 is interpreted as 1.0. Negative values can also be
written to the volume register, causing an inversion of the signal.
Negative values work as expected with the ramp feature; to go
from +1.0 to –1.0 will take 1024 LRCLKs, and the volume will
pass through 0 on the way.
Parameter RAM Contents
Table VI shows the contents of the parameter RAM. The
parameter RAM is 22 bits wide and occupies SPI addresses
Address
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
REV. 0
Table VI. Parameter RAM Contents
Function
IIR0 Left b0
IIR0 Left b1
IIR0 Left b2
IIR0 Left a1
IIR0 Left a2
IIR1 Left b0
IIR1 Left b1
IIR1 Left b2
IIR1 Left a1
IIR1 Left a2
IIR2 Left b0
IIR2 Left b1
IIR2 Left b2
IIR2 Left a1
IIR2 Left a2
IIR3 Left b0
IIR3 Left b1
IIR3 Left b2
IIR3 Left a1
IIR3 Left a2
IIR4 Left b0
IIR4 Left b1
IIR4 Left b2
IIR4 Left a1
IIR4 Left a2
IIR5 Left b0
IIR5 Left b1
IIR5 Left b2
IIR5 Left a1
IIR5 Left a2
IIR6 Left b0
IIR6 Left b1
IIR6 Left b2
IIR6 Left a1
IIR6 Left a2
IIR0 Right b0
Default Value
in Fractional
2.20 Format
1.0
0
0
0
0
1.0
0
0
0
0
1.0
0
0
0
0
1.0
0
0
0
0
1.0
0
0
0
0
1.0
0
0
0
0
1.0
0
0
0
0
1.0
–23–
0–255. The low addresses of the RAM are used to control the
biquad filters. There are 22 biquad filters in all, and each
biquad has five coefficients, resulting in a total memory usage
of 110 coefficients. There are also two tables of 33 coefficients
each that define the main and sub compressor input/output
characteristics. These are loaded with 1.0 on power-up, resulting
in no compression. Other RAM entries control other compressor
characteristics, as well as delay and spatialization settings.
The parameter RAM is initialized on power-up by an on-board
boot ROM. The default values (shown in the table) yield no
equalization, no compression, no spatialization, no delay, and
“normal” detector time constants in the compressor sections.
The functionality of the AD1953 on power-up is basically that
of a normal audio DAC with no signal-processing capability.
The data format of the Parameter RAM is twos complement
2.20 format. This means that the coefficients may range from
+2.0 (–1 LSB) to –2.0, with 1.0 represented by the binary word
0100000000000000000000.
Address
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
Table VI. Parameter RAM Contents (continued)
Function
IIR0 Right b1
IIR0 Right b2
IIR0 Right a1
IIR0 Right a2
IIR1 Right b0
IIR1 Right b1
IIR1 Right b2
IIR1 Right a1
IIR1 Right a2
IIR2 Right b0
IIR2 Right b1
IIR2 Right b2
IIR2 Right a1
IIR2 Right a2
IIR3 Right b0
IIR3 Right b1
IIR3 Right b2
IIR3 Right a1
IIR3 Right a2
IIR4 Right b0
IIR4 Right b1
IIR4 Right b2
IIR4 Right a1
IIR4 Right a2
IIR5 Right b0
IIR5 Right b1
IIR5 Right b2
IIR5 Right a1
IIR5 Right a2
IIR6 Right b0
IIR6 Right b1
IIR6 Right b2
IIR6 Right a1
IIR6 Right a2
IIR0 Xover Left b0
IIR0 Xover Left b1
Default Value
in Fractional
2.20 Format
0
0
0
0
1.0
0
0
0
0
1.0
0
0
0
0
1.0
0
0
0
0
1.0
0
0
0
0
1.0
0
0
0
0
1.0
0
0
0
0
1.0
0
AD1953