Datasheet

AD586
Rev. G | Page 11 of 16
5 V REFERENCE WITH MULTIPLYING
CMOS DACs OR ADCs
The AD586 is ideal for applications with 10- and 12-bit
multiplying CMOS DACs. In the standard hookup, as shown
in Figure 20, the AD586 is paired with the AD7545 12-bit
multiplying DAC and the AD711 high speed BiFET op amp.
The amplifier DAC configuration produces a unipolar 0 V to
−5 V output range. Bipolar output applications and other
operating details can be found in the individual product data
sheets.
AD586
GND
V
OUT
V
IN
AD711K
0.1µF
0.1µF
–15V
0V TO–5V
+15V
OUT 1
AGND
DGND
DB11TO DB0
C1
33pF
R2
68Ω
R
FB
+15V
V
DD
AD7545K
V
REF
10kΩ
V
OUT
TRIM
+15V
2018
196
5
4
2
3
1 2
7
4
6
3
2
00529-019
Figure 20. Low Power 12-Bit CMOS DAC Application
The AD586 can also be used as a precision reference for multi-
ple DACs. Figure 21 shows the AD586, the AD7628 dual DAC,
and the AD712 dual op amp hooked up for single-supply opera-
tion to produce 0 V to −5 V outputs. Because both DACs are on
the same die and share a common reference and output op
amps, the DAC outputs will exhibit similar gain TCs.
AD586
GND
AD712
OUT A
DGND
AGND
DAC A
DB0
DB7
DATA
INPUTS
OUT B
DAC B
RFB B
RFB A
V
REF
A
V
REF
B
AD7628
V
IN
V
OUT
A=
0TO–5V
V
OUT
B=
0TO–5V
V
OUT
+15V
+15V
6 4
4
7
14
2
5
317
1
19
20
2
4
00529-020
Figure 21. AD586 as a 5 V Reference for a CMOS
STACKED PRECISION REFERENCES FOR
MULTIPLE VOLTAGES
Often, a design requires several reference voltages. Three
AD586s can be stacked, as shown in Figure 22, to produce
5.000 V, 10.000 V, and 15.000 V outputs. This scheme can be
extended to any number of AD586s, provided the maximum
load current is not exceeded. This design provides the addi-
tional advantage of improved line regulation on the 5.0 V
output. Changes in V
IN
of 18 V to 50 V produce output changes
that are below the noise level of the references.
22V TO 46V
AD586
GND
V
OUT
V
IN
TRIM
10kΩ
AD586
GND
V
OUT
V
IN
TRIM
AD586
GND
V
OUT
V
IN
TRIM
10kΩ
10kΩ
15V
10V
5V
2
4
5
6
2
4
5
6
2
4
5
6
00529-021
Figure 22. Multiple AD586s Stacked for Precision 5 V, 10 V, and 15 V Outputs
PRECISION CURRENT SOURCE
The design of the AD586 allows it to be easily configured as a
current source. By choosing the control resistor R
C
in Figure 23,
the user can vary the load current from the quiescent current
(typically, 2 mA) to approximately 10 mA. The compliance volt-
age of this circuit varies from about 5 V to 21 V, depending on
the value of V
IN
.
AD586
GND
V
OUT
V
IN
5V
R
C
I
L
= + I
BIAS
+V
IN
R
C
(500Ω MIN)
2
4
6
00529-022
Figure 23. Precision Current Source
PRECISION HIGH CURRENT SUPPLY
For higher currents, the AD586 can easily be connected to a
power PNP or power Darlington PNP device. The circuit in
Figure 24 and Figure 25 can deliver up to 4 amps to the load.
The 0.1 µF capacitor is required only if the load has a significant
capacitive component. If the load is purely resistive, improved
high frequency supply rejection results can be obtained by
removing the capacitor.