AD587TQ Analog Devices, AD587TQ Datasheet - Page 7

• Manufacturer Part Number: AD587TQ
• Description: High Precision 10 V Reference
• Manufacturer: Analog Devices

REV. D
NEGATIVE REFERENCE VOLTAGE FROM AN AD587
The AD587 can be used to provide a precision –10.000 V output
as shown in Figure 11. The V
supply, the output pin is grounded, and the AD587 ground pin
is connected through a resistor, R
–10 V output is now taken from the ground pin (Pin 4) instead
of V
ply resistor R
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 +10 V output configuration.
USING THE AD587 WITH CONVERTERS
The AD587 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.
10 V REFERENCE WITH MULTIPLYING CMOS D/A OR
A/D CONVERTERS
The AD587 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 AD587 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 –10 V output range. Bipolar output applications and other
operating details can be found on the individual product data
sheets.
Figure 12. Low Power 12-Bit CMOS DAC Application
OUT
Figure 11. AD587 as a Negative 10 V Reference
. It is essential to arrange the output load and the sup-
S
so that the net current through the AD587 is be-
1nF
+3.5V
AD587
–15V
GND
V
2
IN
4
R
+26V
S
V
IN
OUT
pin is tied to at least a +3.5 V
2.5mA <
S
, to a –15 V supply. The
6
I
L
R
5V
S
–I
–10V
L
<10mA
–7–
The AD587 can also be used as a precision reference for mul-
tiple DACs. Figure 13 shows the AD587, the AD7628 dual
DAC and the AD712 dual op amp hooked up for single supply
operation to produce 0 V to –10 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.
PRECISION CURRENT SOURCE
The design of the AD587 allows it to be easily configured as a
current source. By choosing the control resistor R
you can vary the load current from the quiescent current (2 mA
typically) to approximately 10 mA.
Figure 13. AD587 as a 10 V Reference for a CMOS Dual
DAC
Figure 14. Precision Current Source
AD587
+V
GND
V
2
IN
4
IN
V
OUT
6
500
MIN
R
C
I
L
=
10V
R
C
+ I
C
AD587
BIAS
in Figure 14,