5962-8982401PA Datasheet, PDF (11/16 Pages) Analog Devices – High Precision 5 V Reference

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.
+15V
2
V_IN
AD586
V_OUT 6
TRIM 5
GND
4
R2
+15V
68Ω
18
V_DD
19 V_REF
20
R_FB
OUT 1 1
10kΩ
AD7545K ^{AGND 2}
DGND
3
DB11 TO DB0
C1 ^+15V
33pF ^0.1µF
2
7
AD711K 6
V_OUT
3
4
0 V TO –5V
0.1µF
–15V
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.
+15V
2
V_IN
V_OUT 6
AD586
GND
4
+15V
V_REFA
4
17 3
RFB A
DAC A
OUT A ₂
DATA
INPUTS
14 _DB0
AD7628
7 DB7
4
V_REFB
DAC B
AGND
1
RFB B
19
OUT B
20
DGND
5
AD712
V_OUT A =
0 TO –5V
V_OUT B =
0 TO –5V
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 VIN of 18 V to 50 V produce output changes
that are below the noise level of the references.
AD586
22V TO 46V
2
V_IN
AD586 ^{VOUT 6}
TRIM 5
GND
4
2
V_IN
AD586 ^{VOUT 6}
TRIM 5
GND
4
2
V_IN
AD586 ^{VOUT 6}
TRIM 5
GND
4
10kΩ
15V
10kΩ
10V
10kΩ
5V
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 RC 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 VIN.
+V_IN
2
V_IN
AD586
GND
4
V_OUT 6
R_C
(500Ω MIN)
I_L
=
5V
R_C
+
I_BIAS
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.
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