Page 1
High Precision
a
FEATURES
Laser Trimmed to High Accuracy:
10.000 V ⴞ5 mV (L and U Grades)
Trimmed Temperature Coefficient:
5 ppm/ⴗC max, (L and U Grades)
Noise Reduction Capability
Low Quiescent Current: 4 mA max
Output Trim Capability
MIL-STD-883 Compliant Versions Available
PRODUCT DESCRIPTION
The AD587 represents a major advance in the state-of-the-art in
monolithic voltage references. Using a proprietary ion-implanted
buried Zener diode and laser wafer trimming of high stability
thin-film resistors, the AD587 provides outstanding performance at low cost.
The AD587 offers much higher performance than most other
10 V references. Because the AD587 uses an industry standard
pinout, many systems can be upgraded instantly with the
AD587. The buried Zener approach to reference design provides lower noise and drift than bandgap voltage references. The
AD587 offers a noise reduction pin which can be used to further
reduce the noise level generated by the buried Zener.
The AD587 is recommended for use as a reference for 8-, 10-,
12-, 14- or 16-bit D/A converters which require an external
precision reference. The device is also ideal for successive
approximation or integrating A/D converters with up to 14 bits
of accuracy and, in general, can offer better performance than
the standard on-chip references.
The AD587J, K and L are specified for operation from 0°C to
+70°C, and the AD587S, T and U are specified for –55°C to
+125°C operation. All grades are available in 8-pin cerdip. The
J and K versions are also available in an 8-pin Small Outline IC
(SOIC) package for surface mount applications, while the J, K,
and L grades also come in an 8-pin plastic package.
10 V Reference
AD587
FUNCTIONAL BLOCK DIAGRAM
IN
2
NOISE
REDUCTION
8
R
S
R
I
4
GND
A1
R
R
T
AD587
V
6
OUT
F
5
TRIM
+V
NOTE:
PINS 1,3, AND 7 ARE INTERNAL TEST POINTS.
NO CONNECTIONS TO THESE POINTS.
PRODUCT HIGHLIGHTS
1. Laser trimming of both initial accuracy and temperature
coefficients results in very low errors over temperature without the use of external components. The AD587L has a
maximum deviation from 10.000 V of ±8.5 mV between 0°C
and +70°C, and the AD587U guarantees ±14 mV maximum
total error between –55°C and +125°C.
2. For applications requiring higher precision, an optional fine
trim connection is provided.
3. Any system using an industry standard pinout 10 volt reference can be upgraded instantly with the AD587.
4. Output noise of the AD587 is very low, typically 4 µV p-p. A
noise reduction pin is provided for additional noise filtering
using an external capacitor.
5. The AD587 is available in versions compliant with MILSTD-883. Refer to the Analog Devices Military Products
Databook or current AD587/883B data sheet for detailed
specifications.
REV. D
Information furnished by Analog Devices is believed to be accurate and
reliable. However, no responsibility is assumed by Analog Devices for its
use, nor for any infringements of patents or other rights of third parties
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781/329-4700 World Wide Web Site: http://www.analog.com
Fax: 781/326-8703 © Analog Devices, Inc., 2000
Page 2
AD587–SPECIFICATIONS
(TA = +25ⴗC, VIN = +15 V unless otherwise noted)
Model AD587J/S AD587K/T AD587L/U
OUTPUT VOLTAGE 9.990 10.010 9.995 10.005 9.995 10.005 V
OUTPUT VOLTAGE DRIFT
0°C to +70°C 20 10 5 ppm/°C
–55°C to +125°C 20105
GAIN ADJUSTMENT +3 +3 +3 %
LINE REGULATION
13.5 V ≤ + VIN ≤ 36 V
T
to T
MIN
MAX
LOAD REGULATION
Sourcing 0 < I
T
to T
MIN
Sourcing –10 < I
T
to T
MIN
QUIESCENT CURRENT 2 4 2 4 2 4 mA
POWER DISSIPATION 30 30 30 mW
OUTPUT NOISE
0.1 Hz to 10 Hz 4 4 4 µV p-p
Spectral Density, 100 Hz 100 100 100 nV/√Hz
LONG-TERM STABILITY 15 15 15 ±ppm/1000 Hr.
SHORT-CIRCUIT CURRENT-TO-GROUND 30 70 30 70 30 70 mA
SHORT-CIRCUIT CURRENT-TO-V
TEMPERATURE RANGE
Specified Performance (J, K, L) 0 +70 0 +70 0 +70 °C
Operating Performance (J, K, L)
Specified Performance (S, T, U) –55 +125 –55 +125 –55 +125
Operating Performance (S, T, U)
NOTES
1
Spec is guaranteed for all packages and grades. Cerdip packaged parts are 100% production test.
2
Load Regulation (Sinking) specification for SOIC (R) package is ±200 µV/mA.
3
The operating temperature ranged is defined as the temperatures extremes at which the device will still function. Parts may deviate from their specified performance
outside their specified temperature range.
Specifications subject to change without notice.
OUT
MAX
MAX
< 10 mA
OUT
1
1
< 0 mA
1
2
IN
3
3
Min Typ Max Min Typ Max Min Typ Max Units
–1 –1 –1
100 100 100 ±µV/V
100 100 100 ±µV/mA
100 100 100
30 70 30 70 30 70 mA
–40 +85 –40 +85 –40 +85
–55 +125 –55 +125 –55 +125
ORDERING GUIDE
Initial Temperature Temperature Package
Error Coefficient Range Options
Model
1
AD587JQ 10 mV 20 ppm/°C0°C to +70°C Q-8
AD587JR 10 mV 20 ppm/°C0°C to +70°C SO-8
AD587JN 10 mV 20 ppm/°C0°C to +70°C N-8
AD587KQ 5 mV 10 ppm/°C0°C to +70°C Q-8
AD587KR 5 mV 10 ppm/°C0°C to +70°C SO-8
AD587KN 5 mV 10 ppm/°C0°C to +70°C N-8
AD587LQ 5 mV 5 ppm/°C0°C to +70°C Q-8
AD587LN 5 mV 5 ppm/°C0°C to +70°C N-8
AD587SQ 10 mV 20 ppm/°C –55°C to +125°C Q-8
AD587TQ 10 mV 10 ppm/°C –55°C to +125°C Q-8
AD587UQ 5 mV 5 ppm/°C –55°C to +125°C Q-8
AD587JCHIPS 10 mV 20 ppm/°C0°C to +70°C
NOTES
1
For details on grade and package offerings screened in accordance with MIL-STD-883, refer to the
Analog Devices Military Products Databook or current AD587/883B data sheet.
2
N = Plastic DIP; Q = Cerdip; SO = SOIC.
2
REV. D–2–
Page 3
AD587
ABSOLUTE MAXIMUM RATINGS*
VIN to Ground . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 V
Power Dissipation (+25°C) . . . . . . . . . . . . . . . . . . . . . 500 mW
Storage Temperature . . . . . . . . . . . . . . . . . . . –65°C to +150°C
Lead Temperature (Soldering, 10 sec) . . . . . . . . . . . . +300°C
Package Thermal Resistance
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22°C/W
θ
JC
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110°C/W
θ
JA
Output Protection: Output safe for indefinite short to ground and
momentary short to V
*Stresses above those listed under Absolute Maximum Ratings may cause perma-
nent damage to the device. This is a stress rating only; functional operation of the
device at these or any other conditions above those indicated in the operational
sections of this specification is not implied. Exposure to absolute maximum rating
conditions for extended periods may affect device reliability.
.
IN
The following specifications are tested at the die level for AD587JCHIPS. These die are probed at +25°C only.
(T
DIE SPECIFICATIONS
= +25°C, V
A
AD587JCHIPS
Parameter Min Typ Max Units
Output Voltage 9.990 10.010 V
Gain Adjustment –1 3 %
Line Regulation
13.5 V < + VIN < 36 V 100 ±µV/V
= +15 V unless otherwise noted)
IN
PIN CONFIGURATION
NOISE
1
TP*
+V
TP*
GND
*TP DENOTES FACTORY TEST POINT.
NO CONNECTIONS SHOULD BE MADE
TO THESE PINS.
IN
AD587
2
TOP VIEW
3
(Not to Scale)
4
8
REDUCTION
7
TP*
6
V
OUT
TRIM
5
DIE LAYOUT
Load Regulation
Sourcing 0 < I
Sinking –10 < I
< 10 mA 100 µV/mA
OUT
< 0 mA 100 µV/mA
OUT
Quiescent Current 2 4 mA
Short-Circuit Current-to-Ground 70 mA
Short-Circuit Currrent-to-V
OUT
NOTES
1
Both V
2
Sense and force grounds must be tied together.
Die Thickness: The standard thickness of Analog Devices Bipolar dice is 24 mils ± 2 mils.
Die Dimensions: The dimensions given have a tolerance of ± 2 mils.
Backing: The standard backside surface is silicon (not plated). Analog Devices does not recommend
gold-backed dice for most applications.
Edges: A diamond saw is used to separate wafers into dice thus providing perpendicular edges halfway through the die.
In contrast to scribed dice, this technique provides a more uniform die shape and size . The perpendicular edges facilitate handling (such as tweezer pick-up) while the uniform shape and size simplifies
substrate design and die attach.
Top Surface: The standard top surface of the die is covered by a layer of glassivation . All areas are
covered except bonding pads and scribe lines.
Surface Metalization: The metalization to Analog Devices bipolar dice is aluminum. Minimum
thickness is 10,000Å.
Bonding Pads: All bonding pads have a minimum size of 4 mils by 4 mils. The passivation windows
have 3.5 mils by 3.5 mils minimum.
pads should be connected to the output.
OUT
70 mA
Die Size: 0.081 × 0.060 Inches
REV. D –3–
Page 4
AD587
THEORY OF OPERATION
The AD587 consists of a proprietary buried Zener diode reference, an amplifier to buffer the output and several high stability
thin-film resistors as shown in the block diagram in Figure 1.
This design results in a high precision monolithic 10 V output
reference with initial offset of 5 mV or less. The temperature
compensation circuitry provides the device with a temperature
coefficient of under 5 ppm/°C.
IN
2
NOISE
REDUCTION
8
R
S
R
I
4
GND
A1
R
R
T
AD587
V
6
OUT
F
5
TRIM
+V
NOTE:
PINS 1,3, AND 7 ARE INTERNAL TEST POINTS.
NO CONNECTIONS TO THESE POINTS.
Figure 1. AD587 Functional Block Diagram
A capacitor can be added at the NOISE REDUCTION pin (Pin
8) to form a low-pass filter with R
to reduce the noise contribu-
S
tion of the Zener to the circuit.
APPLYING THE AD587
The AD587 is simple to use in virtually all precision reference
applications. When power is applied to Pin 2, and Pin 4 is
grounded, Pin 6 provides a 10 V output. No external components are required; the degree of desired absolute accuracy is
achieved simply by selecting the required device grade. The
AD587 requires less than 4 mA quiescent current from an operating supply of +15 V.
Fine trimming may be desired to set the output level to exactly
10.000 V (calibrated to a main system reference). System calibration may also require a reference voltage that is slightly different from 10.000 V, for example, 10.24 V for binary applications.
In either case, the optional trim circuit shown in Figure 2 can
offset the output by as much as 300 mV, if desired, with minimal effect on other device characteristics.
NOISE PERFORMANCE AND REDUCTION
The noise generated by the AD587 is typically less than 4 µV
p-p over the 0.1 Hz to 10 Hz band. Noise in a 1 MHz bandwidth is approximately 200 µV p-p. The dominant source of
this noise is the buried Zener which contributes approximately
100 nV/√Hz. In comparison, the op amp’s contribution is negli-
gible. Figure 3 shows the 0.1 Hz to 10 Hz noise of a typical
AD587. The noise measurement is made with a bandpass filter
made of a 1-pole high-pass filter with a corner frequency at
0.1 Hz and a 2-pole low-pass filter with a corner frequency at
12.6 Hz to create a filter with a 9.922 Hz bandwidth.
Figure 3. 0.1 Hz to 10 Hz Noise
If further noise reduction is desired, an external capacitor may
be added between the NOISE REDUCTION pin and ground as
shown in Figure 2. This capacitor, combined with the 4 kΩ R
S
and the Zener resistances, form a low-pass filter on the output
of the Zener cell. A 1 µF capacitor will have a 3 dB point at
40 Hz, and it will reduce the high frequency (to 1 MHz) noise
to about 160 µV p-p. Figure 4 shows the 1 MHz noise of a typi-
cal AD587 both with and without a 1 µF capacitor.
+V
IN
2
V
OPTIONAL
NOISE
REDUCTION
CAPACITOR
C
1µF
8
N
IN
NOISE
REDUCTION
AD587
GND
4
TRIM
V
6
O
5
OUTPUT
10kΩ
Figure 2. Optional Fine Trim Configuration
Figure 4. Effect of 1 µF Noise Reduction Capacitor on
Broadband Noise
TURN-ON TIME
Upon application of power (cold start), the time required for the
output voltage to reach its final value within a specified error
band is defined as the turn-on settling time. Two components
normally associated with this are: the time for the active circuits
to settle, and the time for the thermal gradients on the chip to
stabilize. Figure 5 shows the turn-on characteristics of the
AD587. It shows the settling to be about 60 µs to 0.01%. Note
the absence of any thermal tails when the horizontal scale is expanded to 1 ms/cm in Figure 5b.
REV. D–4–
Page 5
AD587
Output turn-on time is modified when an external noise reduction capacitor is used. When present, this capacitor acts as an
additional load to the internal Zener diode’s current source, resulting in a somewhat longer turn-on time. In the case of a 1 µF
capacitor, the initial turn-on time is approximately 400 ms to
0.01% (see Figure 5c).
a. Electrical Turn-On
DYNAMIC PERFORMANCE
The output buffer amplifier is designed to provide the AD587
with static and dynamic load regulation superior to less complete references.
Many A/D and D/A converters present transient current loads
to the reference, and poor reference response can degrade the
converter’s performance.
Figure 6 displays the characteristics of the AD587 output amplifier driving a 0 mA to 10 mA load.
V
7.0V
AD587
V
L
1kΩ
10V
0V
OUT
Figure 6a. Transient Load Test Circuit
b. Extended Time Scale
µ
c. Turn-On with 1
F C
N
Figure 5. Turn-On Characteristics
REV. D –5–
Figure 6b. Large-Scale Transient Response
Figure 6c. Fine Scale Settling for Transient Load
Page 6
AD587
In some applications, a varying load may be both resistive and
capacitive in nature, or the load may be connected to the
AD587 by a long capacitive cable.
Figure 7 displays the output amplifier characteristics driving a
1000 pF, 0 mA to 10 mA load.
V
7.0V
AD587
C
L
1000pF
V
L
1kΩ
10V
0V
OUT
Figure 7a. Capacitive Load Transient /Response Test Circuit
Some confusion exists in the area of defining and specifying reference voltage error over temperature. Historically, references
have been characterized using a maximum deviation per degree
Centrigrade; i.e., ppm/°C. However, because of nonlinearities in
temperature characteristics which originated in standard Zener
references (such as “S” type characteristics), most manufacturers have begun to use a maximum limit error band approach to
specify devices. This technique involves the measurement of the
output at three or more different temperatures to specify an output voltage error band.
Figure 9 shows the typical output voltage drift for the AD587L
and illustrates the test methodology. The box in Figure 9 is
bounded on the sides by thc operating temperature extremes,
and on the top and the bottom by the maximum and minimum
output voltages measured over the operating temperature range.
The slope of the diagonal drawn from the lower left to the upper
right corner of the box determines the performance grade of the
device.
Figure 7b. Output Response with Capacitive Load
LOAD REGULATION
The AD587 has excellent load regulation characteristics. Figure
8 shows that varying the load several mA changes the output by
only a few µV.
Figure 8. Typical Load Regulation Characteristics
TEMPERATURE PERFORMANCE
The AD587 is designed for precision reference applications
where temperature performance is critical. Extensive temperature testing ensures that the device’s high level of performance is
maintained over the operating temperature range.
Figure 9. Typical AD587L Temperature Drift
Each AD587J, K, L grade unit is tested at 0°C, +25°C and
+70°C. Each AD587S, T, and U grade unit is tested at –55°C,
+25°C and +125°C. This approach ensures that the variations
of output voltage that occur as the temperature changes within
the specified range will be contained within a box whose diagonal has a slope equal to the maximum specified drift. The position of the box on the vertical scale will change from device to
device as initial error and the shape of the curve vary. The maximum height of the box for the appropriate temperature range
and device grade is shown in Figure 10. Duplication of these
results requires a combination of high accuracy and stable
temperature control in a test system. Evaluation of the AD587
will produce a curve similar to that in Figure 9, but output
readings may vary depending on the test methods and equipment utilized.
Figure 10. Maximum Output Change in mV
REV. D–6–
Page 7
AD587
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
pin is tied to at least a +3.5 V
IN
supply, the output pin is grounded, and the AD587 ground pin
is connected through a resistor, R
, to a –15 V supply. The
S
–10 V output is now taken from the ground pin (Pin 4) instead
of V
ply resistor R
. It is essential to arrange the output load and the sup-
OUT
so that the net current through the AD587 is be-
S
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.
+3.5V → +26V
2
V
IN
V
6
OUT
AD587
GND
1nF
4
R
–15V
S
← I
L
5V
2.5mA < –I
R
S
–10V
L
<10mA
Figure 11. AD587 as a Negative 10 V Reference
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.
The AD587 can also be used as a precision reference for multiple 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.
Figure 13. AD587 as a 10 V Reference for a CMOS Dual
DAC
PRECISION CURRENT SOURCE
The design of the AD587 allows it to be easily configured as a
current source. By choosing the control resistor R
in Figure 14,
C
you can vary the load current from the quiescent current (2 mA
typically) to approximately 10 mA.
+V
IN
10 V REFERENCE WITH MULTIPLYING CMOS D/A OR A/D CONVERTERS
The AD587 is ideal for applications with 10- and 12-bit multiplying 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
2
V
AD587
GND
IN
V
6
OUT
4
R
500Ω
MIN
C
10V
IL = + I
R
C
BIAS
Figure 14. Precision Current Source
REV. D –7–
Page 8
AD587
PRECISION HIGH CURRENT SUPPLY
For higher currents, the AD587 can easily be connected to a
power PNP or power Darlington PNP device. The circuit in
Figure 15 can deliver up to 4 amps to the load. The 0.1 µF
Figure 15a. Precision High-Current Current Source
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.
C1136a–0–2/00 (rev. D)
Figure 15b. Precision High-Current Voltage Source
Mini-DIP (N-8) Package
OUTLINE DIMENSIONS
Dimensions shown in inches and (mm).
Cerdip (Q-8) Package
Small Outline (R-8) Package
PRINTED IN U.S.A.
REV. D–8–
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