AD1955 Analog Devices, AD1955 Datasheet - Page 9

• Manufacturer Part Number: AD1955
• Description: High Performance, Multibit Sigma-delta DAC With Sacd Playback
• Manufacturer: Analog Devices

Audio Outputs
The AD1955 audio outputs sink a current proportional to the input signal, superimposed on a steady state current. The current-to-
voltage (I/V) converters used need to be able to supply this steady state current as well as the signal current or a resistor or current
source can be used to a positive voltage to null this current to center the range of the I/V converters. Active I/V converters should be
used, referenced to FILTR, and should hold the DAC outputs at this voltage level. Passive I/V conversion should not be used as the
DAC performance will be seriously degraded.
Serial Control Port
The AD1955 has an SPI compatible control port to permit programming the internal control registers. The SPI control port is a three
wire serial port. Its format is similar to the Motorola SPI format except that the input data word is 16-bits wide. The serial bit clock
may be completely asynchronous to the sample rate of the DAC. The following figure shows the format of the SPI signal. Note that
the CCLK may be continuous or a 16-clock burst.
SPI REGISTER DEFINITIONS
Table 1: DAC Control Register 0
Bit 13: 12
Data format
00 : PCM
01 : Ext. DF
10 : SACD Slave
11 : SACD
Master
Bit 15
Power Down
0 : Operation
1 : Powered
Down
Note: 0 = Default Setting
Table 2: DAC Control Register 1
Bits 10:9
MCLK
Mode
00 : 256fs
01 : 512fs
10 : 768fs
11 : 384fs
Note: 0 = Default Setting
Table 3: DAC Volume Registers
Bit 15: 2
Volume
14bit, Unsigned
14bit, Unsigned
Note: Default = full volume
Rev. PrF
CLATCH
CCLK
CDATA
Bit 8
Zero Flag
Polarity
0 : Active high
1: Active low
Bit 11: 10
Output Format
00 : Stereo
01 : Not
Allowed
10 : Mono Left
11 : Mono Right
Bit 14
Mute
0 : Not Muted
1 : Muted
D15
Bit 1: 0
SPI Register Address
10 = Left Volume
11 = Right Volume
D14
Bit 7
SACD Bit Rate
0 : 8fs / 64fs
1 : 4fs / 128fs
Bit 9:8
PCM Sample Rate
00 : 48kHz
01 : 96kHz
10 : 192kHz
11 : Rsvd
Bit 6
SACD Mode
0 : Normal
1 : Phase Mode
Bit 7:6
De-Emphasis
Curve Select
00 : None
01 : 44.1kHz
10 : 32kHz
11 : 48kHz
-9-
Bit 5:4
SACD Phase
Select
00 : Phase 0
01 : Phase 1
10 : Phase 2
11 : Phase 3
Bit 5: 4
PCM/ EF Serial
Data Format
00 : I2S
01 : Right-Just
10 : DSP
11 : LEFT-Just
Bit 3
SACD Bit
Inversion
0 : Normal
1 : Inverted
Bit 3: 2
PCM/ EF Serial
Data Width
00 : 24Bits
01 : 20Bits
10 : 18Bits
11 : 16Bits
Bit 2
SACD BCLK to
MCLK Phase
0 : Rising edge
1 : Falling edge
D0
AD1955
Bit 1: 0
SPI Register
Address
00
Bit 1: 0
SPI Register
Address
01