Datasheet
DAC8512
–12–
REV. A
9
18
1
2
17
R1
100k
7
6
R2
5kΩ
P1
100kΩ
5
4
11
0.1µF
–15V
AMP05
10
R
CS
100Ω
0mA ≤ I
OUT
≤ 10mA
2.4µA/ BIT
12
0.1µF
+15V
+15V
0.1µF
4
REF02
6
2
0.1µF
R3
3k
R4
1k
8
6
2
8
DAC8512FZ
1
CS
CLR
5
3
4
LD
SCLK
SDI
7
Figure 31. A High-Compliance, Digitally Controlled
Precision Current Source
A Single-Supply, Programmable Current Source
The circuit in Figure 32 shows how the DAC8512 can be used
with an OP295 single-supply, rail-to-rail output op amp to pro-
vide a digitally programmable current sink from V
SOURCE
that
consumes less than 3.8 mA, maximum. The DAC’s output volt-
age is applied across R1 by placing the 2N2222 transistor in the
OP295’s feedback loop. For the circuit values shown, the full-
scale output current is 1 mA which is given by the following
equation:
I
OUT
=
DW × 4.095V
R1
where DW = DAC8512’s binary digital input code.
FULL-SCALE
ADJUST
A1 = 1/2 OP295
+5V
6
2
8
DAC8512FP
1
CS
CLR
5
3
4
LD
SCLK
SDI
7
3
2
A1
1
+5V
0.1µF
V
S
LOAD
2N2222
R1
4.02kΩ
P1
200Ω
Figure 32. A Single-Supply, Programmable Current
Source
The usable output voltage range of the current sink is +5 V to
+60 V. The low limit of the range is controlled by transistor
saturation, and the high limit is controlled by the collector-base
breakdown voltage of the 2N2222.
A Digitally Programmable Window Detector
A digitally programmable, upper/lower limit detector using two
DAC8512s is shown in Figure 33. The required upper and
lower limits for the test are loaded into each DAC individually
by controlling HDAC/
LDAC. If a signal at the test input is not
within the programmed limits, the output will indicate a logic
zero which will turn the red LED on.
2
1
1/6
74HC05
HDAC/LDAC
CLR
+5V
1kΩ
C1
C2
+5V
12
3
2
1
4
6
7
5
+5V
R1
604Ω
RED LED
T1
34
+5V
R2
604Ω
GREEN LED
T1
PASS/FAIL
C1, C2 = 1/4 CMP-404
1/6
74HC05
V
IN
LD
SCLK
SDI
0.1µF
+5V
2
6
8
DAC8512
1
5
3
4
7
0.1µF
+5V
2
6
8
DAC8512
1
5
3
4
7
0.1µF
Figure 33. A Digitally Programmable Window Detector