Datasheet

AD9709
Rev. B | Page 18 of 32
80
70
60
50
40
30
20
10
022015105
I
AVDD
(mA)
I
OUTFS
(mA)
00606-032
SLEEP MODE OPERATION
The AD9709 has a power-down function that turns off the
output current and reduces the supply current to less than
8.5 mA over the specified supply range of 3.3 V to 5 V and
temperature range. This mode can be activated by applying a
Logic Level 1 to the SLEEP pin. The SLEEP pin logic threshold
is equal to 0.5 × AVDD. This digital input also contains an active
pull-down circuit that ensures the AD9709 remains enabled if
this input is left disconnected. The AD9709 requires less than
50 ns to power down and approximately 5 µs to power back up.
POWER DISSIPATION
The power dissipation, P
D
, of the AD9709 is dependent on several
factors, including
5
.5
Figure 33. I
AVDD
vs. I
OUTFS
• the power supply voltages (AVDD and DVDD1/DVDD2)
35
30
25
20
15
10
5
0
000.40.30.20.1
I
DVDD
(mA)
RATIO ( f
OUT
/ f
CLK
)
125MSPS
100MSPS
65MSPS
25MSPS
5MSPS
0
0606-033
• the full-scale current output (I
OUTFS
)
• the update rate (f
CLK
)
• the reconstructed digital input waveform
The power dissipation is directly proportional to the analog
supply current, I
AVD D
, and the digital supply current, I
DVDD
. I
AV DD
is directly proportional to I
OUTFS
, as shown in Figure 33, and is
insensitive to f
CLK
.
Conversely, I
DVDD
is dependent on the digital input waveform,
f
CLK
, and digital supply (DVDD1/DVDD2). Figure 34 and
Figure 35 show I
DVDD
as a function of full-scale sine wave output
ratios (f
OUT
/f
CLK
) for various update rates with DVDD1 =
DVDD2 = 5 V and DVDD1 = DVDD2 = 3.3 V, respectively.
Note how I
DVDD
is reduced by more than a factor of 2 when
DVDD1/DVDD2 is reduced from 5 V to 3.3 V.
Figure 34. I
DVDD
vs. Ratio @ DVDD1 = DVDD2 = 5 V
18
16
14
12
10
8
6
4
2
0
000.40.30.20.1
I
DVDD
(mA)
RATIO ( f
OUT
/ f
CLK
)
.5
125MSPS
100MSPS
65MSPS
25MSPS
5MSPS
0
0606-034
Figure 35. I
DVDD
vs. Ratio @ DVDD1 = DVDD2 = 3.3 V