EVAL-AD5821AEBZ Analog Devices Inc, EVAL-AD5821AEBZ Datasheet - Page 12

• Manufacturer Part Number: EVAL-AD5821AEBZ
• Description: Evaluation Board I.c.
• Manufacturer: Analog Devices Inc

Specifications of EVAL-AD5821AEBZ

• Number Of Dac's: 1
• Number Of Bits: 10
• Outputs And Type: 1, Single Ended
• Sampling Rate (per Second): 400k
• Data Interface: I²C
• Settling Time: 250µs
• Dac Type: Current
• Voltage Supply Source: Single
• Operating Temperature: -30°C ~ 80°C
• Utilized Ic / Part: AD5821A
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

AD5821A
Table 6. Data Format
Serial Data-
Words
Serial Data
Bits
Input
Register
Function
1
POWER SUPPLY BYPASSING AND GROUNDING
When accuracy is important in an application, it is beneficial
to consider power supply and ground return layout on the PCB.
The PCB for the AD5821A should have separate analog and digital
power supply sections. Where shared AGND and DGND is
necessary, the connection of grounds should be made at only
one point, as close as possible to the AD5821A.
Pay special attention to the layout of the AGND return path and,
and trace it between the voice coil motor and I
any series resistance. Figure 24 shows the output current sink
of the AD5821A and illustrates the importance of reducing the
effective series impedance of AGND and the trace resistance
between the motor and I
Inductor L
is effectively a dc current that results in a voltage drop, V
when the AD5821A is sinking current. The effect of any series
inductance is minimal.
SDA
SCL
SDA
SCL
XSHUTDOWN = soft power-down; X = unused/don’t care; and D9 to D0 = AC data.
START BY
START BY
MASTER
MASTER
C
1
0
1
0
and Resistor R
Bit
15
SD7
R15
XSHUTDOWN
0
0
ADDRESS BYTE
ADDRESS BYTE
0
0
SERIAL BUS
SERIAL BUS
FRAME 1
FRAME 1
1
SINK
1
C
. The current through the voice coil
. The voice coil is modeled using
1
1
1
Bit
14
SD6
R14
X
X
X
X
X
Bit
13
SD5
R13
D9
R/W
R/W
High Byte
AD5821A
AD5821A
ACK BY
ACK BY
SINK
9
9
Bit
12
SD4
R12
D8
PD
PD
to minimize
1
1
Bit
11
SD3
R11
D7
X
X
COIL
Figure 22. Write Operation
Figure 23. Read Operation
D9
D9
MOST SIGNIFICANT
MOST SIGNIFICANT
,
Rev. 0 | Page 12 of 16
Bit
10
SD2
R10
D6
DATA BYTE
DATA BYTE
D8
FRAME 2
D8
FRAME 2
D7
D7
Bit
9
SD1
R9
D5
D6
D6
X
D5
D5
Bit
8
SD0
R8
D4
SHUTDOWN
D4
D4
DGND
Figure 24. Effect of PCB Trace Resistance and Inductance
AD5821A
ACK BY
AD5821A
SDA
ACK BY
SCL
Bit
7
SD7
R7
D3
1
1
DGND
D3
V
D3
DD
Bit
6
SD6
R6
D2
D2
D2
Bit
5
SD5
R5
D1
D1
R
D1
AD5821A
LEAST SIGNIFICANT
LEAST SIGNIFICANT
R
D0
D0
DATA BYTE
DATA BYTE
SENSE
FRAME 3
FRAME 3
SD4
Bit
4
R4
D0
Low Byte
R
L
G
X
G
X
Q1
AGND
VOICE
X
X
Bit
3
SD3
R3
X
COIL
GROUND
RETURN
X
X
V
R
I
R
SINK
BATTERY
L
Bit
2
SD2
R2
X
C
T
C
V
AD5821A
X
AD5821A
ACK BY
X
ACK BY
DROP
TRACE
RESISTANCE
9
9
Bit
1
SD1
R1
X
V
COIL
STOP BY
MASTER
STOP BY
MASTER
Bit
0
SD0
R0
X