ETC AD1584BRT

a
2.5 V to 5.0 V Micropower, Precision
Series Mode Voltage References
AD1582/AD1583/AD1584/AD1585
FUNCTIONAL BLOCK DIAGRAM
FEATURES
Series Reference (2.5 V, 3 V, 4.096 V, 5 V)
Initial Accuracy: ⴞ0.1% max
Temperature Drift: ⴞ50 ppm/ⴗC max
Low Quiescent Current: 65 ␮A max
Current Output Capability: ⴞ5 mA
Wide Supply Range: VIN = VOUT + 200 mV to 12 V
Wideband Noise (10 Hz–10 kHz): 50 ␮V rms
Operating Temperature Range: –40ⴗC to +85ⴗC
Compact, Surface-Mount, SOT-23 Package
VOUT 1
3 VIN
GND 2
AD1582/3/4/5
TOP VIEW
GENERAL DESCRIPTION
TARGET APPLICATIONS
The AD1582, AD1583, AD1584 and AD1585 are a family of
low cost, low power, low dropout, precision bandgap references.
These designs are available as three-terminal (series) devices and
are packaged in the compact SOT-23, 3-pin, surface mount
package. The versatility of these references makes them ideal for
use in battery powered 3 V or 5 V systems where there may be
wide variations in supply voltage and a need to minimize power
dissipation.
1. Portable, Battery Powered Equipment. Notebook Computers, Cellular Phones, Pagers, PDAs, GPSs and DMMs.
These series mode devices (AD1582/AD1583/AD1584/AD1585)
will source or sink up to 5 mA of load current and operate
efficiently with only 200 mV of required headroom. This family
will draw a maximum 65 µA of quiescent current with only a
1.0 µA/V variation with supply voltage. The advantage of these
designs over conventional shunt devices is extraordinary. Valuable
supply current is no longer wasted through an input series
resistor and maximum power efficiency is achieved at all input
voltage levels.
The AD1582, AD1583, AD1584 and AD1585 are available in
two grades, A and B, both of which are provided in the smallest
available package on the market, the SOT-23. Both grades are
specified over the industrial temperature range of –40°C to
+85°C.
3. Smart Industrial Transmitters.
4. PCMCIA Cards.
5. Automotive.
6. Hard Disk Drives.
7. 3 V/5 V 8-Bit–12-Bit Data Converters.
900
800
700
600
ISUPPLY – ␮A
The superior accuracy and temperature stability of the AD1582/
AD1583/AD1584/AD1585 is made possible by the precise
matching and thermal tracking of on-chip components. Patented
temperature drift curvature correction design techniques have
been used to minimize the nonlinearities in the voltage output
temperature characteristic.
2. Computer Workstations. Suitable for use with a wide range
of video RAMDACs.
SHUNT REFERENCE*
500
400
300
200
100
0
2.7
AD1582 SERIES REFERENCE
VSUPPLY – V
5
*3.076k⍀ SOURCE RESISTOR
Figure 1. Supply Current (µ A) vs. Supply Voltage (V)
REV. A
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
AD1582/AD1583/AD1584/AD1585
AD1582–SPECIFICATIONS (@ T = T
A
MIN–TMAX,
Model
OUTPUT VOLTAGE (@ +25°C)
VIN = 5 V, unless otherwise noted)
Min
AD1582A
Typ
Max
Min
2.48
2.50
2.52
2.498
1
OUTPUT VOLTAGE TEMPERATURE DRIFT
MINIMUM SUPPLY HEADROOM (VIN–VOUT)
With IOUT = 1 mA
AD1582B
Typ
2.500
100
200
Max
Units
2.502
V
50
ppm/°C
200
mV
LOAD REGULATION
0 mA < IOUT < 5 mA
–5 mA < IOUT < 0 mA
200
250
200
250
µV/mA
µV/mA
LOAD REGULATION
–100 µA < IOUT < 100 µA
2
2
mV/mA
LINE REGULATION
VOUT +200 mV < VIN < 12 V
IOUT = 0 mA
25
25
µV/V
RIPPLE REJECTION (∆VOUT/∆VIN)
VIN = 5 V ± 100 mV (f = 120 Hz)2
80
80
dB
QUIESCENT CURRENT
65
65
µA
SHORT CIRCUIT CURRENT TO GROUND
15
15
mA
NOISE VOLTAGE (@ +25°C)
0.1 Hz to 10 Hz
10 Hz to 10 kHz
70
50
TURN-ON SETTLING TIME TO 0.1%3
µV p-p
µV rms
70
50
100
100
µs
LONG-TERM STABILITY
1000 Hours @ +25°C4
100
100
ppm/1000 hrs.
OUTPUT VOLTAGE HYSTERESIS5
115
115
ppm
TEMPERATURE RANGE
Specified Performance (A, B)
Operating Performance (A, B)6
–40
–55
+85
+125
–40
–55
+85
+125
°C
°C
NOTES
1
Maximum output voltage drift is guaranteed for all grades.
2
Ripple Rejection over a wide frequency spectrum is shown in Figure 15.
3
Measured with a capacitance load of 0.2 µF.
4
Long-term stability at +125°C = 1600 ppm/1000 hours.
5
Hysteresis is defined as the change in the 25°C output voltage, caused by bringing the device to +85°C, taking a 25°C measurement and then bringing it to –40°C, followed
by another 25°C measurement. Refer to Figure 12.
6
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
the specified temperature range.
Specifications subject to change without notice.
–2–
REV. A
AD1582/AD1583/AD1584/AD1585
AD1583–SPECIFICATIONS (@ T = T
A
MIN–TMAX,
Model
OUTPUT VOLTAGE (@ +25°C)
VIN = 5 V, unless otherwise noted)
Min
AD1583A
Typ
Max
Min
2.97
3.00
3.03
2.997
OUTPUT VOLTAGE TEMPERATURE DRIFT1
MINIMUM SUPPLY HEADROOM (VIN–VOUT)
With IOUT = 1 mA
AD1583B
Typ
3.000
100
200
Max
Units
3.003
V
50
ppm/°C
200
mV
LOAD REGULATION
0 mA < IOUT < 5 mA
–5 mA < IOUT < 0 mA
250
400
250
400
µV/mA
µV/mA
LOAD REGULATION
–100 µA < IOUT < 100 µA
2.4
2.4
mV/mA
LINE REGULATION
VOUT +200 mV < VIN < 12 V
IOUT = 0 mA
25
25
µV/V
RIPPLE REJECTION (∆VOUT/∆VIN)
VIN = 5 V ± 100 mV (f = 120 Hz)2
80
80
dB
QUIESCENT CURRENT
65
65
µA
SHORT CIRCUIT CURRENT TO GROUND
15
15
mA
NOISE VOLTAGE (@ +25°C)
0.1 Hz to 10 Hz
10 Hz to 10 kHz
85
60
TURN-ON SETTLING TIME TO 0.1%3
µV p-p
µV rms
85
60
120
120
µs
LONG-TERM STABILITY
1000 Hours @ +25°C
100
100
ppm/1000 hrs.
OUTPUT VOLTAGE HYSTERESIS4
115
115
ppm
TEMPERATURE RANGE
Specified Performance (A, B)
Operating Performance (A, B)5
–40
–55
+85
+125
–40
–55
+85
+125
°C
°C
NOTES
1
Maximum output voltage drift is guaranteed for all grades.
2
Ripple Rejection over a wide frequency spectrum is shown in Figure 15.
3
Measured with a capacitance load of 0.2 µF.
4
Hysteresis is defined as the change in the 25°C output voltage, caused by bringing the device to +85°C, taking a 25°C measurement and then bringing it to –40°C, followed
by another 25°C measurement. Refer to Figure 12.
5
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
the specified temperature range.
Specifications subject to change without notice.
REV. A
–3–
AD1582/AD1583/AD1584/AD1585
AD1584–SPECIFICATIONS (@ T = T
A
MIN–TMAX,
Model
Min
OUTPUT VOLTAGE (@ +25°C)
VIN = 5 V, unless otherwise noted)
AD1584A
Typ
4.056
4.096
1
OUTPUT VOLTAGE TEMPERATURE DRIFT
MINIMUM SUPPLY HEADROOM (VIN–VOUT)
With IOUT = 1 mA
AD1584B
Typ
Max
Min
4.136
4.092
4.096
100
200
Max
Units
4.100
V
50
ppm/°C
200
mV
LOAD REGULATION
0 mA < IOUT < 5 mA
–5 mA < IOUT < 0 mA
320
320
320
320
µV/mA
µV/mA
LOAD REGULATION
–100 µA < IOUT < 100 µA
3.2
3.2
mV/mA
LINE REGULATION
VOUT +200 mV < VIN < 12 V
IOUT = 0 mA
25
25
µV/V
RIPPLE REJECTION (∆VOUT/∆VIN)
VIN = 5 V ± 100 mV (f = 120 Hz)2
80
80
dB
QUIESCENT CURRENT
65
65
µA
SHORT CIRCUIT CURRENT TO GROUND
15
15
mA
NOISE VOLTAGE (@ +25°C)
0.1 Hz to 10 Hz
10 Hz to 10 kHz
110
90
TURN-ON SETTLING TIME TO 0.1%3
µV p-p
µV rms
110
90
140
140
µs
LONG-TERM STABILITY
1000 Hours @ +25°C
100
100
ppm/1000 hrs.
OUTPUT VOLTAGE HYSTERESIS4
115
115
ppm
TEMPERATURE RANGE
Specified Performance (A, B)
Operating Performance (A, B)5
–40
–55
+85
+125
–40
–55
+85
+125
°C
°C
NOTES
1
Maximum output voltage drift is guaranteed for all grades.
2
Ripple Rejection over a wide frequency spectrum is shown in Figure 15.
3
Measured with a capacitance load of 0.2 µF.
4
Hysteresis is defined as the change in the 25°C output voltage, caused by bringing the device to +85°C, taking a 25°C measurement and then bringing it to –40°C, followed
by another 25°C measurement. Refer to Figure 12.
5
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
the specified temperature range.
Specifications subject to change without notice.
–4–
REV. A
AD1582/AD1583/AD1584/AD1585
AD1585–SPECIFICATIONS (@ T = T
A
MIN–TMAX,
Model
OUTPUT VOLTAGE (@ +25°C)
VIN = 6 V, unless otherwise noted)
Min
AD1585A
Typ
Max
Min
4.95
5.00
5.05
4.995
1
OUTPUT VOLTAGE TEMPERATURE DRIFT
MINIMUM SUPPLY HEADROOM (VIN–VOUT)
With IOUT = 1 mA
AD1585B
Typ
5.000
100
200
Max
Units
5.005
V
50
ppm/°C
200
mV
LOAD REGULATION
0 mA < IOUT < 5 mA
–5 mA < IOUT < 0 mA
400
400
400
400
µV/mA
µV/mA
LOAD REGULATION
–100 µA < IOUT < 100 µA
4
4
mV/mA
LINE REGULATION
VOUT +200 mV < VIN < 12 V
IOUT = 0 mA
25
25
µV/V
RIPPLE REJECTION (∆VOUT/∆VIN)
VIN = 6 V ± 100 mV (f = 120 Hz)2
80
80
dB
QUIESCENT CURRENT
65
65
µA
SHORT CIRCUIT CURRENT TO GROUND
15
15
mA
NOISE VOLTAGE (@ +25°C)
0.1 Hz to 10 Hz
10 Hz to 10 kHz
140
100
TURN-ON SETTLING TIME TO 0.1%3
µV p-p
µV rms
140
100
175
175
µs
LONG-TERM STABILITY
1000 Hours @ +25°C
100
100
ppm/1000 hrs.
OUTPUT VOLTAGE HYSTERESIS4
115
115
ppm
TEMPERATURE RANGE
Specified Performance (A, B)
Operating Performance (A, B)5
–40
–55
+85
+125
–40
–55
+85
+125
°C
°C
NOTES
1
Maximum output voltage drift is guaranteed for all grades.
2
Ripple Rejection over a wide frequency spectrum is shown in Figure 15.
3
Measured with a capacitance load of 0.2 µF.
4
Hysteresis is defined as the change in the 25°C output voltage, caused by bringing the device to +85°C, taking a 25°C measurement and then bringing it to –40°C, followed
by another 25°C measurement. Refer to Figure 12.
5
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
the specified temperature range.
Specifications subject to change without notice.
REV. A
–5–
AD1582/AD1583/AD1584/AD1585
ABSOLUTE MAXIMUM RATINGS 1
PACKAGE BRANDING INFORMATION
VIN to Ground . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 V
Internal Power Dissipation2
SOT-23 (RT) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 400 mW
Storage Temperature Range . . . . . . . . . . . . –65°C to +125°C
Operating Temperature Range
AD1582/AD1583/AD1584/AD1585RT . . . –40°C to +85°C
Lead Temperature, Soldering
Vapor Phase (60 sec) . . . . . . . . . . . . . . . . . . . . . . . . +215°C
Infrared (15 sec) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +220°C
Four marking fields identify the device generic, grade and date
of processing. The first field is the product identifier. A “2/3/4/5”
identifies the generic as the AD1582/3/4/5. The second field
indicates the device grade; “A” or “B.” In the third field a
numeral or letter indicates the calendar year; “7” for 1997. . . ,
“A” for 2001. . . The fourth field uses letters A-Z to represent a
two week window within the calendar year, starting with “A” for
the first two weeks of January.
NOTES
1
Stresses above those listed under Absolute Maximum Ratings may cause
permanent 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 section of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect device reliability.
2
Specification is for device in free air at 25°C: SOT-23 Package: θJA = 300°C/W.
ORDERING GUIDE
Model1
Initial Output
Error
Temperature
Coefficient
AD1582/AD1583/AD1584/AD1585ART
AD1582/AD1583/AD1584/AD1585ARTRL2
AD1582/AD1583/AD1584/AD1585ARTRL73
AD1582/AD1583/AD1584/AD1585BRT
AD1582/AD1583/AD1584/AD1585BRTRL2
AD1582/AD1583/AD1584/AD1585BRTRL73
1.0%
1.0%
1.0%
0.1%
0.1%
0.1%
100 ppm/°C
100 ppm/°C
100 ppm/°C
50 ppm/°C
50 ppm/°C
50 ppm/°C
NOTES
1
Package Option for all Models; RT = Surface Mount, SOT-23.
2
Provided on a 13-inch reel containing 10,000 pieces.
3
Provided on a 7-inch reel containing 3,000 pieces.
CAUTION
ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily
accumulate on the human body and test equipment and can discharge without detection.
Although the AD1582/AD1583/AD1584/AD1585 feature 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.
–6–
REV. A
Typical Performance Characteristics– AD1582/AD1583/AD1584/AD1585
0.40
22
20
0.35
18
0.30
1585
0.25
14
mV/mA
# OF PARTS
16
12
10
0.20
1582
0.15
8
6
0.10
4
0.05
2
0
–60 –50 –40 –30 –20 –10 0
ppm/ⴗC
10
20
30
40
0
50
0
Figure 2. Typical Output Voltage Temperature Drift
Distribution
4
6
VIN – Volts
8
10
12
Figure 5. Load Regulation vs. VIN
50
0
45
–10
40
–20
35
–30
30
␮V/V
# OF PARTS
2
25
–40
1582
–50
20
–60
15
1585
–70
10
–80
5
0
–100%
–0.60%
–0.20%
0.20%
VOUT – ERROR
0.60%
–90
–5
1.00%
Figure 3. Typical Output Voltage Error Distribution
–4
–3
–2
–1
0
1
IOUT – mA
2
3
4
5
Figure 6. Line Regulation vs. ILOAD
1E+04
2.510
2.508
2.506
IOUT = 1mA
nV/ Hz
VOUT
2.504
2.502
2.500
IOUT = 0
1E+03
2.498
2.496
2.494
2.492
–60
–40
–20
0
20
40
60
TEMPERATURE – ⴗC
80
100
1E+02
1E+01
120
Figure 4. Typical Temperature Drift Characteristic Curves
REV. A
1E+02
1E+03
FREQUENCY – Hz
1E+04
Figure 7. Noise Spectral Density
–7–
1E+05
AD1582/AD1583/AD1584/AD1585
THEORY OF OPERATION
The AD1582/AD1583/AD1584/AD1585 family uses the
“bandgap” concept to produce stable, low temperature coefficient voltage references suitable for high accuracy data acquisition components and systems. This family of precision references
makes use of the underlying temperature characteristics of a
silicon transistor’s base-emitter voltage in the forward biased
operating region. Under this condition, all such transistors have
a –2 mV/°C temperature coefficient (TC) and a VBE that, when
extrapolated to absolute zero, 0°K, (with collector current proportional to absolute temperature) approximates the silicon bandgap
voltage. By summing a voltage that has an equal and opposite
temperature coefficient of +2 mV/°C with the VBE of a forwardbiased transistor, a zero TC reference can be developed. In the
AD1582/AD1583/AD1584/AD1585 simplified circuit diagram
shown in Figure 8, such a compensating voltage, V1, is derived
by driving two transistors at different current densities and
amplifying the resultant VBE difference (∆VBE—which has a
positive TC). The sum (VBG) of VBE and V1 is then buffered
and amplified to produce stable reference voltage outputs of
2.5 V, 3 V, 4.096 V, and 5 V.
R3
+
VOUT
–
The AD1582/AD1583/AD1584/AD1585 family of references is
designed for applications where temperature performance is
important. Extensive temperature testing and characterization
ensures that the device’s performance is maintained over the
specified temperature range.
Some confusion exists, however, in the area of defining and
specifying reference voltage error over temperature. Historically,
references have been characterized using a maximum deviation
per degree centigrade, i.e., 50 ppm/°C. However, because of the
inconsistent nonlinearities in standard zener references (such as
“S” type characteristics), most manufacturers use a maximum
limit error band approach to characterize their references. Using
this technique, the voltage reference output voltage error band is
specified by taking output voltage measurements at three or
more different temperatures.
The error band guaranteed with the AD1582/AD1583/AD1584/
AD1585 family is the maximum deviation from the initial value
at +25°C; this method is of more use to a designer than the one
which simply guarantees the maximum error band over the
entire temperature change. Thus, for a given grade of the
AD1582/AD1583/AD1584/AD1585, the designer can easily
determine the maximum total error by summing initial accuracy
and temperature variation (e.g., for the AD1582BRT, the initial
tolerance is ± 2 mV, the temperature error band is ± 8 mV, thus
the reference is guaranteed to be 2.5 V ± 10 mV from –40°C to
+85°C).
R5
VBG
R1
R6
+
V1
–
2
VIN
4.7␮F
TEMPERATURE PERFORMANCE
VOUT
+
VBE R2
–
3
1␮F
Figure 9. Typical Connection Diagram
VIN
R4
1
GND
Figure 8. Simplified Schematic
APPLYING THE AD1582/AD1583/AD1584/AD1585
Figure 10 shows the typical output voltage drift for the AD1582
and illustrates the methodology. The box in Figure 10 is bounded
on the x-axis by operating temperature extremes, and on the yaxis by the maximum and minimum output voltages observed
over the operating temperature range. The slope of the diagonal
drawn from the initial output value at +25°C to the output
values at +85°C and –40°C determines the performance grade
of the device.
The AD1582/AD1583/AD1584/AD1585 is a family of series
references that can be utilized for many applications. To achieve
optimum performance with these references, only two external
components are required. Figure 9 shows the AD1582 configured for operation under all loading conditions. With a simple
4.7 µF capacitor attached to the input and a 1 µF capacitor
applied to the output, the devices will achieve specified performance for all input voltage and output current requirements.
For best transient response, add a 0.1 µF capacitor in parallel with
the 4.7 µF. While a 1 µF output capacitor will provide stable
performance for all loading conditions, the AD1582 can operate
under low (–100 µA < I OUT < 100 µA) current conditions with
just a 0.2 µF output capacitor. The 4.7 µF capacitor on the input
can be reduced to 1 µF in this condition.
Duplication of these results requires a test system that is highly
accurate with stable temperature control. Evaluation of the
AD1582 will produce curves similar to those in Figures 4 and
10, but output readings may vary depending upon the test
methods and test equipment utilized.
Unlike conventional shunt reference designs, the AD1582/
AD1583/AD1584/AD1585 family provides stable output
voltages at constant operating current levels. When properly
decoupled, as shown in Figure 9, these devices can be applied to
any circuit and provide superior low power solutions.
–8–
REV. A
AD1582/AD1583/AD1584/AD1585
hysteresis, the AD1582/AD1583/AD1584/AD1585 family
is designed to minimize this characteristic. This phenomenon can be quantified by measuring the change in the
+25°C output voltage after temperature excursions from
+85°C to +25°C, and –40°C to +25°C. Figure 12 displays
the distribution of the AD1582 output voltage hysteresis.
2.510
2.509
2.508
VOUT – Volts
2.507
2.506
2.505
80
2.504
70
2.503
60
2.501
–60
–40
–20
0
20
40
60
TEMPERATURE – ⴗC
80
100
# OF PARTS
2.502
120
Figure 10. Output Voltage vs. Temperature
50
40
30
20
VOLTAGE OUTPUT NONLINEARITY VS. TEMPERATURE
When using a voltage reference with data converters, it is
important to understand the impact that temperature drift can
have on the converter’s performance. The nonlinearity of the
reference output drift represents additional error that cannot
easily be calibrated out of the overall system. To better understand the impact such a drift can have on a data converter, refer
to Figure 11 where the measured drift characteristic is normalized to the end point average drift. The residual drift error of the
AD1582 of approximately 200 ppm demonstrates that this
family of references is compatible with systems that require
12-bit accurate temperature performance.
250
200
10
0
–700
50
ppm
300
550
SUPPLY CURRENT VS. TEMPERATURE
The quiescent current for the AD1582/AD1583/AD1584/
AD1585 family of references will vary slightly over temperature and input supply range. Figure 13 demonstrates the
typical performance for the AD1582 reference when varying
both temperature and supply voltage. As is evident from the
graph, the AD1582 supply current increases only 1.0 µA/V,
making this device extremely attractive for use in applications where there may be wide variations in supply voltage
and a need to minimize power dissipation.
100
100
80
50
TA = 85ⴗC
0
–50
–50
TA = 25ⴗC
IQ – ␮A
60
40
–25
0
25
50
TEMPERATURE – ⴗC
75
100
TA = –40ⴗC
20
Figure 11. Residual Drift Error
OUTPUT VOLTAGE HYSTERESIS
0
High performance industrial equipment manufacturers may
require the AD1582/AD1583/AD1584/AD1585 family to
maintain a consistent output voltage error at +25°C after the
references are operated over the full temperature range. While
all references exhibit a characteristic known as output voltage
REV. A
–200
Figure 12. Output Voltage Hysteresis Distribution
150
VOUT ⌬ – ppm
–450
3
4
5
6
7
8
VIN – Volts
9
10
11
Figure 13. Typical Supply Current over Temperature
–9–
AD1582/AD1583/AD1584/AD1585
AC PERFORMANCE
100
To successfully apply the AD1582/AD1583/AD1584/AD1585
family of references, it is important to understand the effects of
dynamic output impedance and power supply rejection. In
Figure 14a, a voltage divider is formed by the AD1582’s output
impedance and the external source impedance. Figure 14b
shows the effect of varying the load capacitor on the reference
output. Power supply rejection ratio (PSRR) should be determined when characterizing the ac performance of a series
voltage reference. Figure 15a shows a test circuit used to
measure PSRR, and Figure 15b demonstrates the AD1582’s
ability to attenuate line voltage ripple.
VLOAD DC
70
PSRR – dB
1582
X1
ⴞ100␮A
1585
40
20
10
1.E+01
1.E+02
1.E+03
1.E+04
FREQUENCY – Hz
NOISE PERFORMANCE AND REDUCTION
1␮F
1␮F CAP
10
1585
1582
1
The noise generated by the AD1582 is typically less then
70 µV p-p over the 0.1 Hz to 10 Hz frequency band. Figure 16
shows the 0.1 Hz to 10 Hz noise of a typical AD1582. The noise
measurement is made with a high gain bandpass filter. Noise in
a 10 Hz to 10 kHz region is approximately 50 µV rms. Figure 17
shows the broadband noise of a typical AD1582. If further noise
reduction is desired, a 1-pole low-pass filter may be added
between the output pin and ground. A time constant of 0.2 ms
will have a –3 dB point at roughly 800 Hz, and will reduce the
high frequency noise to about 16 µV rms. It should be noted,
however, that while additional filtering on the output may improve
the noise performance of the AD1582/AD1583/AD1584/AD1585
family, the added output impedance could degrade the ac
performance of the references.
10 ␮V
1E+03
1E+04
FREQUENCY – Hz
1.E+06
Figure 15b. Ripple Rejection vs. Frequency
100
1E+02
1.E+05
5␮F
Figure 14a. Output Impedance Test Circuit
OHM
50
0
1.E+00
DUT
10k⍀
60
30
5V
10k⍀
0.1
1E+01
80
2k⍀
10k⍀
2X VOUT
ⴞ2V
90
1E+05
1E+06
1s
100
90
Figure 14b. Output Impedance vs. Frequency
10V
10k⍀
ⴞ200mV
10k⍀
10
0%
5V ⴞ100mV
X1
0.22␮F
DUT
VOUT
0.22␮F
Figure 16. 0.1–10 Hz Voltage Noise
Figure 15a. Ripple Rejection Test Circuit
100␮V
10ms
100
90
10
0%
Figure 17. 10 Hz to 10 kHz Wideband Noise
–10–
REV. A
AD1582/AD1583/AD1584/AD1585
TURN-ON TIME
DYNAMIC PERFORMANCE
Many low power instrument manufacturers are becoming
increasingly concerned with the turn-on characteristics of the
components being used in their systems. Fast turn-on components often enable the end user to save power by keeping power
off when it is not needed. Turn-on settling time is defined as the
time required, after the application of power (cold start), for the
output voltage to reach its final value within a specified error.
The two major factors affecting this are the active circuit settling
time and the time required for the thermal gradients on the chip
to stabilize. Figure 18a shows the turn-on settling and transient
response test circuit. Figure 18b displays the turn-on characteristic of the AD1582. This characteristic is generated from coldstart operation and represents the true turn-on waveform after
power up. Figure 18c shows the fine settling characteristics of
the AD1582. Typically, the reference settles to within 0.1% of
its final value in about 100 µs.
Many A/D and D/A converters present transient current loads
to the reference, and poor reference response can degrade the
converter’s performance. The AD1582/3/4/5 family of references has been designed to provide superior static and dynamic
line and load regulation. Since these series references are
capable of both sourcing and sinking large current loads, they
exhibit excellent settling characteristics.
The device can momentarily draw excessive supply current
when VSUPPLY is slightly below the minimum specified level.
Power supply resistance must be low enough to ensure reliable
turn-on. Fast power supply edges minimize this effect.
Figure 19 displays the line transient response for the AD1582.
The circuit utilized to perform such a measurement is displayed
in Figure 18a, where the input supply voltage is toggled from
5 V to 10 V and the input and output capacitors are each 0.22 µF.
Figures 20 and 21 show the load transient settling characteristics for the AD1582 when load current steps of 0 mA to 5 mA
and 0 mA to –1 mA are applied. The input supply voltage
remains constant at 5 V, the input decoupling and output load
capacitors are 4.7 µF and 1 µF respectively, and the output current
is toggled. For both positive and negative current loads, the
reference responses settle very quickly and exhibit initial voltage
spikes less than 10 mV.
10k⍀
5V OR 10V
0V OR 5V
0V OR 10V
X1
0V TO 10V
0.22␮F
10k⍀
DUT
5V
50␮s
200mV
50␮s
100
90
VOUT
0.22␮F
Figure 18a. Turn-On/Transient Response Test Circuit
10
0%
5V
20␮s
Figure 19. Line Transient Response
100
90
5V
20␮s
100
90
10
0%
1V
20␮s
Figure 18b. Turn-On Characteristics
10
0%
5mV
5V
20␮s
20␮s
Figure 20. Load Transient Response (0 mA to 5 mA Load)
100
90
5V
20␮s
100
90
10
0%
1mV
20␮s
Figure 18c. Turn-On Settling
10
0%
5mV
20␮s
Figure 21. Load Transient Response
(0 mA to –1 mA Load)
REV. A
–11–
AD1582/AD1583/AD1584/AD1585
OUTLINE DIMENSIONS
Dimensions shown in inches and (mm).
Surface Mount Package
SOT-23
3
0.055 (1.397)
0.0470 (1.194)
1
2
C2976–0–3/00 (rev. A)
0.1200 (3.048)
0.1102 (2.799)
0.1040 (2.642)
0.0827 (2.101)
PIN 1
0.0236 (0.599)
0.0177 (0.450)
0.0413 (1.049)
0.0374 (0.950)
0.0807 (2.050)
0.0701 (1.781)
0.0059 (0.150)
0.0034 (0.086)
0.0440 (1.118)
0.0320 (0.813)
0.0040 (0.102)
0.0005 (0.013)
SEATING
PLANE
0.0210 (0.533)
0.0146 (0.371)
0.0100 (0.254)
0.0050 (0.127)
0.027 (0.686)
REF
TAPE AND REEL DIMENSIONS
Dimensions shown in millimeters.
1.8 ⴞ 0.1
14.4 MAX
0.30
ⴞ 0.05
4.0 ⴞ 0.10
1.5 MIN
2.0 ⴞ 0.05
1.75
ⴞ 0.10
3.5
ⴞ 0.05
8.0
ⴞ 0.30
180 (7")
OR
330 (13")
20.2
MIN
13.0
ⴞ 0.2
50 (7" REEL) MIN
OR
100 (13" REEL) MIN
0.75
MIN
3.1 ⴞ 0.1
DIRECTION OF UNREELING
2.7
ⴞ 0.1
1.0 MIN
+ 1.5
8.4 – 0.0
PRINTED IN U.S.A.
+0.05
1.5 –0.00
–12–
REV. A