AD586
NEGATIVE REFERENCE VOLTAGE FROM AN AD586
The AD586 can be used to provide a precision –5.000 V output
as shown in Figure 11. The V
IN
pin is tied to at least a +6 V
supply, the output pin is grounded, and the AD586 ground pin
is connected through a resistor, R
S
, to a –15 V supply. The –5 V
output is now taken from the ground pin (Pin 4) instead of
V
OUT.
It is essential to arrange the output load and the supply
resistor R
S
so that the net current through the AD586 is be-
tween 2.5 mA and 10.0 mA. The temperature characteristics
and long-term stability of the device will be essentially the same
as that of a unit used in the standard +5 V output configuration.
Figure 13. AD586 as a 5 V Reference for a CMOS
Dual DAC
STACKED PRECISION REFERENCES FOR
MULTIPLE VOLTAGES
Figure 11. AD586 as a Negative 5 V Reference
USING THE AD586 WITH CONVERTERS
The AD586 is an ideal reference for a wide variety of 8-, 12-,
14- and 16-bit A/D and D/A converters. Several representative
examples follow.
5 V REFERENCE WITH MULTIPLYING CMOS D/A OR
A/D CONVERTERS
Often, a design requires several reference voltages. Three
AD586s can be stacked, as shown in Figure 14, to produce
+5.000 V, +10.000 V, and +15.000 V outputs. This scheme
can be extended to any number of AD586s as long as the
maximum load current is not exceeded. This design pro-
vides the additional advantage of improved line regulation
on the +5.0 V output. Changes in V
IN
of +18 V to +50 V
produces an output change that is below the noise level of
the references.
The AD586 is ideal for applications with 10- and 12-bit multi-
plying CMOS D/A converters. In the standard hookup, as
shown in Figure 12, 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 on the individual product data
sheets.
Figure 14. Multiple AD586s Stacked for Precision 5 V,
10 V and 15 V Outputs
Figure 12. Low-Power 12-Bit CMOS DAC Application
The AD586 can also be used as a precision reference for mul-
tiple DACs. Figure 13 shows the AD586, the AD7628 dual
DAC and the AD712 dual op amp hooked up for single supply
operation 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.
REV. C
–7–
AD [ ANALOG DEVICES ]
