10-9
Standard Measurement Conditions and
Description
V
DD
= 5.0V.
V
REF
= 2.0V.
R = 200
.
16R = 3.3k
.
T
A
= 25
o
C.
V
REF
in Figure 9 is fixed to 2V
DC
without resistor dividing.
Input data in Figure 10 = all “0” and “1” of rectangular wave,
clock frequency = 50MHz for a total value of three channels.
Notes On Operation
Selecting the Output Resistance:
HI2309 is a current output type D/A converter. To create the
output voltage, connect the resistor to the current output pin.
Specifications:
Output full scale voltage V
FS
Max = 2.0 [V].
Output full scale current I
FS
Max = 10 [mA].
Calculate the output resistance from V
FS
= I
FS
x R. Connect
a resistance sixteen times the output resistance to the refer-
ence current pin I
REF
. In some cases, this value may not
exist, a similar value can be used instead.
Note that the V
FS
will be the following:
V
FS
= V
REF
x 16 R/R’.
R is the resistor to be connected to the IO and R’ is the
resistor to be connected to the I
REF
. Power consumption
can be reduced by increasing the resistance, but this will on
the contrary, increase the glitch energy and data setting
time. Set the best values according to the purpose of use.
Correlation Between Data and Clock:
For HI2309 to display the desired performance as a D/A con-
verter, the data transmitted from outside and the clock must
be synchronized properly. Adjust the setup time (t
S
) and
hold time (t
H
) as specified in “Electrical Characteristics.”
V
DD
, V
SS
:
Separate the analog and digital signals around the device to
reduce noise effects. Bypass the V
DD
pin to each GND with
a 0.1
μ
F ceramic capacitor as near as possible to the pin for
both digital and analog signals.
Latch Up:
The AV
DD
and DV
DD
pins must be able to share the same
power supply of the board. This is to prevent latch up caused
by potential difference between the two pins when the power
is turned on.
I
REF
Pin:
The I
REF
pin is very sensitive to improve the AC
Characteristics. Pay attention for capacitance component
not to attach to this pin because its output may become
unstable.
VG Pin:
It is recommended to use a 1
μ
F capacitor to improve the AC
Characteristics, though the typical capacitance value
externally connected to the V
G
Pin is 0.1
μ
F.
FIGURE 9. OUTPUT FULL SCALE VOLTAGE vs AMBIENT
TEMPERATURE
FIGURE 10. OUTPUT FREQUENCY vs CURRENT
CONSUMPTION
Typical Performance Curves
(Continued)
1.95
1.90
O
0
-25
0
25
50
75
AMBIENT TEMPERATURE (
o
C)
V = 0.02mV/
o
C
50
40
10
1
5
10
15
20
OUTPUT FREQUENCY (MHz)
C