AD587JNZ ,High Precision 10 V Referenceapplications requiring higher precision, an optional fine10 V references. Because the AD587 uses an ..
AD587JNZ ,High Precision 10 V ReferenceSPECIFICATIONS (T = 25C, V = 15 V, unless otherwise noted.)A IN AD587J AD5 ..
AD587JQ ,High Precision 10 V Referencespecifications.the standard on-chip references.The AD587J, K and L are specified for operation from ..
AD587JR ,High Precision 10 V ReferenceSPECIFICATIONSA INDIE LAYOUT AD587JCHIPSParameter Min Typ Max UnitsOutput Voltage 9.990 10.010 VG ..
AD587JR. ,High Precision 10 V Referencespecifications are tested at the die level for AD587JCHIPS. These die are probed at +25
5962-8982503PA-AD587JNZ
High Precision 10 V Reference
REV.F
High Precision
10 V Reference
FEATURES
Laser Trimmed to High Accuracy:
10.000 V � 5 mV (L and U Grades)
Trimmed Temperature Coefficient:
5 ppm/�C Max (L and U Grades)
Noise Reduction Capability
Low Quiescent Current: 4 mA Max
Output Trim Capability
MIL-STD-883 Compliant Versions Available
FUNCTIONAL BLOCK DIAGRAM
GENERAL DESCRIPTIONThe AD587 represents a major advance in state-of-the-art
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 band gap voltage references. The AD587
offers a noise reduction pin that 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 DACs that require an external precision reference.
The device is also ideal for successive approximation or integrat-
ing ADCs with up to 14 bits of accuracy and, in general, can
offer better performance than the standard on-chip references.
The AD587J, AD587K, and AD587L are specified for operation
from 0°C to 70°C, and the AD587U is specified for –55°C to
+125°C operation. All grades are available in 8-lead CERDIP.
The J and K versions are also available in an 8-lead SOIC package
for surface-mount applications, while the J, K, and L grades also
come in an 8-lead PDIP.
PRODUCT HIGHLIGHTSLaser 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.For applications requiring higher precision, an optional fine
trim connection is provided.Any system using an industry-standard pinout 10 V reference
can be upgraded instantly with the AD587.Output noise of the AD587 is very low, typically 4 µV p-p.noise reduction pin is provided for additional noise filtering
using an external capacitor.The AD587 is available in versions compliant with
MIL-STD-883. Refer to the Analog Devices Military Products
Databook or the current AD587/883B Data Sheet for detailed
specifications.
AD587–SPECIFICATIONS(TA = 25�C, VIN = 15 V, unless otherwise noted.)SHORT-CIRCUIT
TEMPERATURE RANGE
NOTESSpecification is guaranteed for all packages and grades. CERDIP packaged parts are 100% production tested.Load regulation (sinking) specification for SOIC (R) package is ±200 µV/mA.The operating temperature range is defined as the temperature 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.
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
�JC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22°C/W
�JA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .110°C/W
Output Protection: Output safe for indefinite short to ground
and momentary short to +VIN.
*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.
PIN CONFIGURATION
CAUTIONESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000V readily
accumulate on the human body and test equipment and can discharge without detection. Although the
AD587 features proprietary ESD protection circuitry, permanent damage may occur on devices
subjected to high energy electrostatic discharges. Therefore, proper ESD precautions are recommended
to avoid performance degradation or loss of functionality.
ORDERING GUIDENOTESN = PDIP; Q = CERDIP; R = SOIC.Z = Pb-free part.
AD587
THEORY OF OPERATIONThe AD587 consists of a proprietary buried Zener diode refer-
ence, 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.
Figure 1. Functional Block Diagram
A capacitor can be added at the NOISE REDUCTION pin
(Pin 8) to form a low-pass filter with RS to reduce the noise
contribution of the Zener to the circuit.
APPLYING THE AD587The 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 15V.
Fine trimming may be desired to set the output level to exactly
10.000 V (calibrated to a main system reference). System calibra-
tion 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 Figure2 can offset
the output by as much as 300mV with minimal effect on other
device characteristics.
Figure 2. Optional Fine Trim Configuration
NOISE PERFORMANCE AND REDUCTIONThe 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 negligible. Figure3
shows the 0.1 Hz to 10 Hz noise of a typical AD587. The noise
measurement is made with a band-pass 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
4kΩRS and the Zener resistances, forms a low-pass filter on the
output of the Zener cell. A 1 µF capacitor will have a 3 dB point
at 40Hz, and 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.
Figure 4. Effect of 1 µF Noise Reduction Capacitor
on Broadband Noise
TURN-ON TIMEUpon 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.
Output turn-on time is modified when an external noise reduc-
tion 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
b. Extended Time Scale
c. Turn-On with 1 µF CN
Figure 5. Turn-On Characteristics
DYNAMIC PERFORMANCEThe output buffer amplifier is designed to provide the AD587
with static and dynamic load regulation superior to less complete
references.
Many ADCs and DACs present transient current loads to the
reference, and poor reference response can degrade the converter’s
performance.
Figures 6b and 6c display the characteristics of the AD587 output
amplifier driving a 0 mA to 10 mA load.
Figure 6a. Transient Load Test Circuit
Figure 6b. Large-Scale Transient Response
Figure 6c. Fine Scale Setting for Transient Load
AD587In 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 7b displays the output amplifier characteristics driving a
1000 pF, 0 mA to 10 mA load.
Figure 7a. Capacitive Load Transient /Response
Test Circuit
Figure 7b. Output Response with Capacitive Load
LOAD REGULATIONThe 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 PERFORMANCEThe 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.
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
Celsius; i.e., ppm/°C. However, because of nonlinearities in
temperature characteristics that 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 the 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.
TEMPERATURE – �C80Figure 9. Typical AD587L Temperature Drift
Each AD587J, AD587K, and AD587L grade unit is tested at 0°C,
25°C, and 70°C. Each AD587U 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
acurve similar to that in Figure 9, but output readings may vary
depending on the test methods and equipment utilized.
