ADR512WARTZ-R7 [ADI]
1.2 V Precision Low Noise Shunt Voltage Reference;
| 型号： | ADR512WARTZ-R7 |
| 厂家： | 
ADI |
| 描述： | 1.2 V Precision Low Noise Shunt Voltage Reference 光电二极管 |
| 文件： | 总12页 (文件大小：300K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
1.2 V Precision Low Noise
Shunt Voltage Reference
ADR512W
FEATURES
PIN CONFIGURATION
Precision 1.200 V voltage reference
Ultracompact 3-lead SOT-23 package
No external capacitor required
ADR512W
V+
1
3
TRIM/NC
Low output noise: 4 µV p-p (0.1 Hz to 10 Hz)
Initial accuracy: 0.67% maximum
Temperature coefficient: 60 ppm/°C maximum
Operating current range: 100 µA to 10 mA
Output impedance: 0.3 Ω maximum
Temperature range: −40°C to +85°C
Qualified for automotive applications
TOP VIEW
(Not to Scale)
V–
2
NC = NO CONNECT. DO NOT
CONNECT TO THIS PIN.
Figure 1. 3-Lead SOT-23
APPLICATIONS
Automotive systems
Precision data acquisition systems
Microcontroller reference voltage
GENERAL DESCRIPTION
Designed for space critical applications, the ADR512W is a low
voltage (1.200 V), precision shunt-mode voltage reference in the
ultracompact SOT-23 package. The ADR512W features low
temperature drift (60 ppm/°C), high accuracy ( 0.67%), and
ultralow noise (4 µV p-p) performance.
minimum operating current increases from a scant 100 µA to a
maximum of 10 mA.
A TRIM terminal is available on the ADR512W to provide
adjustment of the output voltage over 0.5% without affecting
the temperature coefficient of the device. This feature provides
users with the flexibility to trim out any system errors.
The ADR512W’s advanced design eliminates the need for an
external capacitor, yet it is stable with any capacitive load. The
V
S
I
+ I
Q
R
L
BIAS
I
L
V
= 1.2V
OUT
C
OUT
AD512W
I
Q
(OPTIONAL)
V
– V
OUT
S
I
R
=
BIAS
+ I
L
Q
Figure 2. Typical Operating Circuit
Rev. 0
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
rightsof third parties that may result fromits use. Specifications subject to change without notice. No
license is granted by implication or otherwise under any patent or patent rights of Analog Devices.
Trademarks andregisteredtrademarks are the property of their respective owners.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
Fax: 781.461.3113
www.analog.com
©2011 Analog Devices, Inc. All rights reserved.
ADR512W
TABLE OF CONTENTS
Features .............................................................................................. 1
Typical Performance Characteristics ..............................................5
Terminology.......................................................................................7
Applications Information .................................................................8
Adjustable Precision Voltage Source ..........................................8
Output Voltage Trim.....................................................................8
Using the ADR512W with Precision Data Converters ............8
Precise Negative Voltage Reference ............................................8
Outline Dimensions....................................................................... 10
Ordering Guide .......................................................................... 10
Automotive Products................................................................. 10
Applications....................................................................................... 1
Pin Configuration............................................................................. 1
General Description ......................................................................... 1
Revision History ............................................................................... 2
Specifications..................................................................................... 3
Electrical Characteristics............................................................. 3
Absolute Maximum Ratings............................................................ 4
Thermal Resistance ...................................................................... 4
ESD Caution.................................................................................. 4
REVISION HISTORY
5/11—Revision 0: Initial Version
Rev. 0 | Page 2 of 12
ADR512W
SPECIFICATIONS
ELECTRICAL CHARACTERISTICS
IIN = 100 µA to 10 mA at TA = 25°C, unless otherwise noted.
Table 1.
Parameter
Output Voltage1
Initial Accuracy
Temperature Coefficient A Grade
Output Voltage Change vs. IIN
Dynamic Output Impedence
Minimum Operating Current
Voltage Noise
Turn-On Settling Time2
Output Voltage Hysteresis
Symbol
VO
VOERR
TCVO
ΔVR
(ΔVR/ΔIR)
IIN
eN p-p
tR
Test Conditions/Comments
Min
Typ
Max
1.208
+8.0
60
3
0.3
Unit
V
mV
ppm/°C
mV
Ω
µA
µV p-p
µs
1.192
−8.0
1.2
−40°C < TA < +85°C
IIN = 0.1 mA to 10 mA
IIN = 1 mA 100 µA
−40°C < TA < +85°C
f = 0.1 Hz to 10 Hz
100
4
10
50
To within 0.1% of output
VO_HYS
ppm
1 The forward diode voltage characteristic at −1 mA is typically 0.65 V.
2 Measured without a load capacitor.
Rev. 0 | Page 3 of 12
ADR512W
ABSOLUTE MAXIMUM RATINGS
Table 2.
THERMAL RESISTANCE
θJA is specified for the worst-case conditions, that is, a device
soldered in a circuit board for surface-mount packages.
Parameter
Rating
25 mA
20 mA
Reverse Current
Forward Current
Table 3. Thermal Resistance
Package Type1
Storage Temperature Range
RT Package
Operating Temperature Range
Junction Temperature Range
RT Package
2
θJA
θJC
Unit
−65°C to +150°C
−40°C to +85°C
3-SOT-23 (RT)
230
146
°C/W
1Package power dissipation = (TJMAX − TA)/θJA.
2θJA is specified for worst-case conditions; that is., θJA is specified for the device
soldered.
−65°C to +150°C
300°C
ESD CAUTION
Lead Temperature Range (Soldering, 60 Sec)
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.
Rev. 0 | Page 4 of 12
ADR512W
TYPICAL PERFORMANCE CHARACTERISTICS
1.204
1.203
1.202
1.201
1.200
V
= 2V/DIV
IN
1.199
1.198
1.197
1.196
V
= 1V/DIV
OUT
TIME (400µs/DIV)
–40
–15
10
35
60
85
TEMPERATURE (°C)
Figure 3. Typical VOUT vs. Temperature
Figure 6. Turn-Off Time
V
= 2V/DIV
IN
V
= 2V/DIV
IN
V
OUT
= 1V/DIV
V
= 1V/DIV
OUT
TIME (100µs/DIV)
TIME (200µs/DIV)
Figure 4. Turn-On Time
Figure 7. Turn-Off Time with a 1 μF Input Capacitor
ΔI = 100µA
IN
V
= 2V/DIV
IN
V
OUT
= 1V/DIV
V
= 20mV/DIV
OUT
TIME (100µs/DIV)
TIME (2µs/DIV)
Figure 5. Turn-On Time with a 1 μF Input Capacitor
Figure 8. Output Response to a 100 μA Input Current Change
Rev. 0 | Page 5 of 12
ADR512W
ΔI = 100µA
IN
2µV/DIV
V
= 20mV/DIV
OUT
TIME (2µs/DIV)
TIME (400ms/DIV)
Figure 9. Output Response to a 100 μA Input Current Change with a
1 μF Capacitor
Figure 10. 0.1 Hz to 10 Hz Noise
Rev. 0 | Page 6 of 12
ADR512W
TERMINOLOGY
Temperature Coefficient
Thermal Hysteresis
Temperature coefficient is the change in output voltage with
respect to operating temperature changes, normalized by the
output voltage at 25°C. This parameter is expressed in ppm/°C
and can be determined with the following equation:
Thermal hysteresis is defined as the change in output voltage
after the device is cycled through temperature from +25°C to
−40°C to +85°C and back to +25°C. This is a typical value from
a sample of parts put through such a cycle.
VO
(
T2
)
− VO
(
T1
)
ppm
VO _ HYS =VO (25°C) −VO _TC
×106
(1)
TCVO
=
°C
VO
(
25°C
)
×
(
T2 − T1
)
(2)
VO
(
25°C
)
−VO _TC
VO _ HYS
[
ppm
]
=
×106
VO 25°C
(
)
where:
VO(25°C) = VO at 25°C.
where:
VO(25°C) = VO at 25°C.
O_TC = VO at 25°C after temperature cycles from +25°C to
−40°C to +85°C and back to +25°C.
VO(T1) = VO at Temperature 1.
VO(T2) = VO at Temperature 2.
V
Rev. 0 | Page 7 of 12
ADR512W
APPLICATIONS INFORMATION
The ADR512W is a 1.2 V precision shunt voltage reference. It is
designed to operate without an external output capacitor
between the positive and negative terminals for stability. An
external capacitor can be used for additional filtering of the
supply.
OUTPUT VOLTAGE TRIM
Using a mechanical or digital potentiometer, the output voltage
of the ADR512W can be trimmed ±0.5%. The circuit in Figure 12
illustrates how the output voltage can be trimmed using a 10 k
potentiometer.
Ω
As with all shunt voltage references, an external bias resistor
(RBIAS) is required between the supply voltage and the
ADR512W (see Figure 2). RBIAS sets the current that is required
to pass through the load (IL) and the ADR512W (IQ). The load
and the supply voltage can vary, thus RBIAS is chosen as follows:
V
CC
R
BIAS
V
OUT
POT
50kΩ
ADR512W
R1
100kΩ
•
RBIAS must be small enough to supply the minimum IQ
current to the ADR512W even when the supply voltage is
at its minimum and the load current is at its maximum
value.
Figure 12. Output Voltage Trim
USING THE ADR512W WITH PRECISION DATA
CONVERTERS
•
RBIAS also must be large enough so that IQ does not exceed
10 mA when the supply voltage is at its maximum and the
load current is at its minimum.
The compact ADR512W package and the device’s low
minimum operating current requirement make it ideal for use
in battery powered portable instruments, such as the AD7533
CMOS multiplying DAC, that use precision data converters.
Given these conditions, RBIAS is determined by the supply
voltage (VS), the load and operating current (IL and IQ) of the
ADR512W, and the ADR512W’s output voltage.
Figure 13 shows the ADR512W serving as an external reference
to the AD7533, a CMOS multiplying DAC. Such a DAC
requires a negative voltage input to provide a positive output
range. In this application, the ADR512W supplies a −1.2 V
reference to the REF input of the AD7533.
R
BIAS = (VS − VOUT)/(IL + IQ)
(3)
ADJUSTABLE PRECISION VOLTAGE SOURCE
The ADR512W, combined with a precision low input bias op
amp such as the AD8610, can be used to output a precise
adjustable voltage. Figure 11 illustrates the implementation of this
application using the ADR512W.
0
9
MSB
LSB
+
–
ADR512W
V
DD
1
AD7533
15
The output of the op amp, VOUT, is determined by the gain of the
circuit, which is completely dependent on resistors R2 and R1.
1
3
G
N
R2
2
1
R2
VOUT =1 +
(4)
–V
R1
DD
+
V
= 0V TO 1.2V
An additional capacitor in parallel with R2 can be added to
filter out high frequency noise. The value of C2 is dependent on
the value of R2.
OUT
–
Figure 13. The ADR512W as a Reference for a 10-Bit CMOS DAC (AD7533)
V
CC
PRECISE NEGATIVE VOLTAGE REFERENCE
R
BIAS
The ADR512W is suitable for use in applications where a
precise negative voltage reference is desired, including the
application detailed in Figure 13.
1.2V
AD8610
R2
V
= 1.2V
OUT
(1 + R2/R1)
ADR512W
Figure 14 shows the ADR512W configured to provide a −1.2 V
output.
R1
C2 (OPTIONAL)
Figure 11. Adjustable Precision Voltage Source
Rev. 0 | Page 8 of 12
ADR512W
R1 in Figure 14 should be chosen so that 100 μA to 10 mA is
provided to properly bias the ADR512W.
+
–
ADR512W
VDD
–1.2V
R1 =
(5)
I
R2
The resistor, R1, should be chosen so that power dissipation is
at a minimum. An ideal resistor value can be determined
through manipulation of Equation 5.
–V
DD
Figure 14. Precise −1.2 V Reference Configuration
Because the ADR512W characteristics resemble those of a
Zener diode, the cathode shown in Figure 14 is 1.2 V higher
with respect to the anode (V+ with respect to V− on the
ADR512W package). Because the cathode of the ADR512W is
tied to ground, the anode must be −1.2 V.
Rev. 0 | Page 9 of 12
ADR512W
OUTLINE DIMENSIONS
3.04
2.90
2.80
1.40
1.30
1.20
3
2.64
2.10
1
2
0.60
0.45
1.03
0.89
2.05
1.78
1.02
0.54
REF
0.95
0.88
GAUGE
PLANE
1.12
0.89
0.100
0.013
0.180
0.085
0.51
0.37
SEATING
PLANE
0.25
0.60 MAX
0.30 MIN
COMPLIANT TO JEDEC STANDARDS TO-236-AB
Figure 15. 3-Lead Small Outline Transistor Package [SOT-23-3]
(RT-3)
Dimensions shown in millimeters
ORDERING GUIDE
Initial Accuracy
Output
Voltage
(VO)
Temperature
Coefficient
(ppm/°C)
Number of
Parts per
Reel
Package
Description
Package
Option
Temperature
Range
1,2
Model
ADR512WARTZ-R7
(mV)
(%)
0.7
Branding
1.2
8.0
60
3-Lead SOT-23-3
RT-3
R1R
3,000
−40°C to +85°C
1 Z = RoHS Compliant Part.
2 W = Qualified for Automotive Applications.
AUTOMOTIVE PRODUCTS
The ADR512W model is available with controlled manufacturing to support the quality and reliability requirements of automotive
applications. Note that this automotive model may have specifications that differ from the commercial models; therefore, designers
should review the Specifications section of this data sheet carefully. Only the automotive grade product shown is available for use in
automotive applications. Contact your local Analog Devices account representative for specific product ordering information and to
obtain the specific Automotive Reliability reports for this model.
Rev. 0 | Page 10 of 12
ADR512W
NOTES
Rev. 0 | Page 11 of 12
ADR512W
NOTES
©2011 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
D09938-0-5/11(0)
Rev. 0 | Page 12 of 12
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