AD5664 Analog Devices, AD5664 Datasheet - Page 16

• Manufacturer Part Number: AD5664
• Manufacturer: Analog Devices

Specifications of AD5664

• Resolution (bits): 16bit
• Dac Update Rate: 223kSPS
• Dac Settling Time: 4µs
• Max Pos Supply (v): +5.5V
• Single-supply: Yes
• Dac Type: Voltage Out
• Dac Input Format: Ser,SPI

AD5624/AD5664
INPUT SHIFT REGISTER
The input shift register is 24 bits wide The first two bits are
don’t care bits. The next three bits are the Command bits, C2 to
C0 (see Table 7), followed by the 3-bit DAC address, A2 to A0
(see Table 8), and then the 16-, 12-bit data-word. The data-word
comprises the 16-, 12- bit input code followed by 0 or 4 don’t
care bits for the AD5664 and AD5624 respectively (see Figure
31 and Figure 32). These data bits are transferred to the DAC
register on the 24
Table 7. Command Definition
C2
0
0
0
0
1
1
1
1
Table 8. Address Command
A2
0
0
0
0
1
SCLK
SYNC
DIN
C1
0
0
1
1
0
0
1
1
A1
0
0
1
1
1
DB23 (MSB)
DB23 (MSB)
SYNC HIGH BEFORE 24
C0
0
1
0
1
0
1
0
1
X
X
DB23
th
INVALID WRITE SEQUENCE:
X
X
falling edge of SCLK.
Command
Write to input register n
Update DAC register n
Write to input register n, update all
(software LDAC)
Write to and update DAC channel n
Power down DAC (power-up)
Reset
Load LDAC register
Reserved
COMMAND BITS
COMMAND BITS
C2
C2
A0
0
1
0
1
1
C1
C1
TH
C0
C0
FALLING EDGE
ADDRESS (n)
DAC A
DAC B
DAC C
DAC D
All DACs
ADDRESS BITS
ADDRESS BITS
A2
A2
DB0
A1
A1
A0
A0
Figure 31. AD5664 Input Shift Register Contents
Figure 32. AD5624 Input Shift Register Contents
D15
D11
D14
D10
Figure 33. SYNC Interrupt Facility
D13
D9
Rev. 0 | Page 16 of 24
D12
D8
D11
D7
DATA BITS
D10
D6
SYNC INTERRUPT
In a normal write sequence, the SYNC line is kept low for at least
24 falling edges of SCLK, and the DAC is updated on the 24
falling edge. However, if SYNC is brought high before the 24
falling edge, then this acts as an interrupt to the write sequence.
The input shift register is reset and the write sequence is seen as
invalid. Neither an update of the DAC register contents nor a
change in the operating mode occurs (see Figure 33).
POWER-ON RESET
The AD5624/AD5664 family contains a power-on reset circuit
that controls the output voltage during power-up. The AD5624/
AD5664 DAC outputs power up to 0 V and the output remains
there until a valid write sequence is made to the DAC. This is
useful in applications where it is important to know the state of
the output of the DAC while it is in the process of powering up.
D9
D5
VALID WRITE SEQUENCE, OUTPUT UPDATES
D8
D4
DATA BITS
DB23
ON THE 24
D7
D3
D6
D2
TH
D5
D1
FALLING EDGE
D4
D0
D3
X
DB0
D2
X
D1
DB0 (LSB)
DB0 (LSB)
X
D0
X
th
th