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Ultralow Noise XFET(R) Voltage References with Current Sink and Source Capability
ADR430/ADR431/ADR433/ADR434/ADR435/ADR439
FEATURES
Low noise (0.1 Hz to 10 Hz): 3.5 V p-p @ 2.5 V output No external capacitor required Low temperature coefficient A Grade: 10 ppm/C max B Grade: 3 ppm/C max Load regulation: 15 ppm/mA Line regulation: 20 ppm/V Wide operating range ADR430: 4.1 V to 18 V ADR431: 4.5 V to 18 V ADR433: 5.0 V to 18 V ADR434: 6.1 V to 18 V ADR435: 7.0 V to 18 V ADR439: 6.5 V to 18 V High output current: +30 mA/-20 mA Wide temperature range: -40C to +125C
PIN CONFIGURATIONS
TP 1 VIN 2 NC 3 NC TOP VIEW 6 VOUT (Not to Scale) GND 4 5 TRIM
7
ADR43x
8
TP
NC = NO CONNECT
Figure 1. 8-Lead MSOP (RM Suffix)
TP 1 VIN 2
NC = NO CONNECT
APPLICATIONS
Precision data acquisition systems High resolution data converters Medical instruments Industrial process control systems Optical control circuits Precision instruments
Figure 2. 8-Lead SOIC (R Suffix)
GENERAL DESCRIPTION
The ADR43x series is a family of XFET voltage references featuring low noise, high accuracy, and low temperature drift performance. Using ADI's patented temperature drift curvature correction and XFET (eXtra implanted junction FET) technology, the ADR43x's voltage change versus temperature nonlinearity is minimized. The XFET references operate at lower current (800 A) and supply headroom (2 V) than buried-Zener references. BuriedZener references require more than 5 V headroom for operations. The ADR43x XFET references are the only low noise solutions for 5 V systems. The ADR43x series has the capability to source up to 30 mA and sink up to 20 mA of output current. It also comes with a TRIM terminal to adjust the output voltage over a 0.5% range without compromising performance. The ADR43x is available in the 8-lead mini SOIC and 8-lead SOIC packages. All versions are specified over the extended industrial temperature range (-40C to +125C). Table 1. Selection Guide
Model ADR430B ADR430A ADR431B ADR431A ADR433B ADR433A ADR434B ADR434A ADR435B ADR435A ADR439B ADR439A VOUT (V) 2.048 2.048 2.500 2.500 3.000 3.000 4.096 4.096 5.000 5.000 4.500 4.500 Accuracy (mV) 1 3 1 3 1.4 4 1.5 5 2 6 2 5.4 Temperature Coefficient (ppm/C) 3 10 3 10 3 10 3 10 3 10 3 10
Rev. B
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 that may result from its 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 and registered trademarks 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 www.analog.com Fax: 781.326.8703 (c) 2004 Analog Devices, Inc. All rights reserved.
04500-0-041
NC TOP VIEW NC 3 (Not to Scale) 6 VOUT 5 TRIM GND 4
7
ADR43x
8
TP
04500-0-001
ADR430/ADR431/ADR433/ADR434/ADR435/ADR439
TABLE OF CONTENTS
Specifications..................................................................................... 3 ADR430 Electrical Characteristics............................................. 3 ADR431 Electrical Characteristics............................................. 4 ADR433 Electrical Characteristics............................................. 5 ADR434 Electrical Characteristics............................................. 6 ADR435 Electrical Characteristics............................................. 7 ADR439 Electrical Characteristics............................................. 8 Absolute Maximum Ratings............................................................ 9 Package Type ................................................................................. 9 ESD Caution.................................................................................. 9 Typical Performance Characteristics ........................................... 10 Theory of Operation ...................................................................... 15 Basic Voltage Reference Connections...................................... 15 Noise Performance ..................................................................... 15 Turn-On Time ............................................................................ 15 Applications..................................................................................... 16 Output Adjustment .................................................................... 16 Reference for Converters in Optical Network Control Circuits......................................................................................... 16 Negative Precision Reference without Precision Resistors ... 16 High Voltage Floating Current Source .................................... 17 Kelvin Connections.................................................................... 17 Dual Polarity References ........................................................... 17 Programmable Current Source ................................................ 18 Programmable DAC Reference Voltage .................................. 18 Precision Voltage Reference for Data Converters.................. 19 Precision Boosted Output Regulator ....................................... 19 Outline Dimensions ....................................................................... 20 Ordering Guide .......................................................................... 21
REVISION HISTORY
9/04--Data Sheet Changed from Rev. A to Rev. B Added New Grade ..............................................................Universal Changes to Specifications ................................................................ 3 Replaced Figure 3, Figure 4, Figure 5........................................... 10 Updated Ordering Guide............................................................... 21 6/04--Data Sheet Changed from Rev. 0 to Rev. A Changes to Format .............................................................Universal Changes to the Ordering Guide.................................................... 20 12/03--Revision 0: Initial Version
Rev. B | Page 2 of 24
ADR430/ADR431/ADR433/ADR434/ADR435/ADR439
SPECIFICATIONS
ADR430 ELECTRICAL CHARACTERISTICS
VIN = 4.1 V to 18 V, ILOAD = 0 mA, TA = 25C, unless otherwise noted. Table 2.
Parameter Output Voltage B Grade A Grade Initial Accuracy B Grade B Grade A Grade A Grade Temperature Coefficient SOIC-8 (B Grade) SOIC-8 (A Grade) MSOP-8 Line Regulation Load Regulation Symbol VO VO VOERR VOERR VOERR VOERR TCVO TCVO TCVO VO/VIN VO/ILOAD -40C < TA < +125C -40C < TA < +125C -40C < TA < +125C VIN = 4.1 V to 18 V -40C < TA < +125C ILOAD = 0 mA to 10 mA, VIN = 5.0 V -40C < TA < +125C ILOAD = -10 mA to 0 mA, VIN = 5.0 V -40C < TA < +125C No load, -40C < TA < +125C 0.1 Hz to 10.0 Hz 1 kHz CIN = 0 1,000 h fIN = 10 kHz 4.1 2 1 2 2 5 Conditions Min 2.047 2.045 Typ 2.048 2.048 Max 2.049 2.051 1 0.05 3 0.15 3 10 10 20 15 15 800 Unit V V mV % mV % ppm/C ppm/C ppm/V ppm/mA ppm/mA A V p-p nVHz s ppm ppm dB mA V V
Quiescent Current Voltage Noise Voltage Noise Density Turn-On Settling Time Long-Term Stability1 Output Voltage Hysteresis Ripple Rejection Ratio Short Circuit to GND Supply Voltage Operating Range Supply Voltage Headroom
IIN eN p-p eN tR VO VO_HYS RRR ISC VIN VIN - VO
560 3.5 60 10 40 20 -70 40
18
1
The long-term stability specification is noncumulative. The drift in subsequent 1,000 hour periods is significantly lower than in the first 1,000 hour period.
Rev. B | Page 3 of 24
ADR430/ADR431/ADR433/ADR434/ADR435/ADR439
ADR431 ELECTRICAL CHARACTERISTICS
VIN = 4.5 V to 18 V, ILOAD = 0 mA, TA = 25C, unless otherwise noted. Table 3.
Parameter Output Voltage B Grade A Grade Initial Accuracy B Grade B Grade A Grade A Grade Temperature Coefficient SOIC-8 (B Grade) SOIC-8 (A Grade) MSOP-8 Line Regulation Load Regulation Symbol VO VO VOERR VOERR VOERR VOERR TCVO TCVO TCVO VO/VIN VO/ILOAD -40C < TA < +125C -40C < TA < +125C -40C < TA < +125C VIN = 4.5 V to 18 V -40C < TA < +125C ILOAD = 0 mA to 10 mA, VIN = 5.0 V -40C < TA < +125C ILOAD = -10 mA to 0 mA, VIN = 5.0 V -40C < TA < +125C No load, -40C < TA < +125C 0.1 Hz to 10.0 Hz 1 kHz CIN = 0 1,000 h fIN = 10 kHz 4.5 2 15 15 800 ppm/mA ppm/mA A V p-p nVHz s ppm ppm dB mA V V 1 2 2 5 Conditions Min 2.499 2.497 Typ 2.500 2.500 Max 2.501 2.503 1 0.04 3 0.13 3 10 10 20 Unit V V mV % mV % ppm/C ppm/C ppm/C ppm/V
Quiescent Current Voltage Noise Voltage Noise Density Turn-On Settling Time Long-Term Stability1 Output Voltage Hysteresis Ripple Rejection Ratio Short Circuit to GND Supply Voltage Operating Range Supply Voltage Headroom
IIN eN p-p eN tR VO VO_HYS RRR ISC VIN VIN - VO
580 3.5 80 10 40 20 -70 40
18
1
The long-term stability specification is noncumulative. The drift in subsequent 1,000 hour periods is significantly lower than in the first 1,000 hour period.
Rev. B | Page 4 of 24
ADR430/ADR431/ADR433/ADR434/ADR435/ADR439
ADR433 ELECTRICAL CHARACTERISTICS
VIN = 5 V to 18 V, ILOAD = 0 mA , TA = 25C, unless otherwise noted. Table 4.
Parameter Output Voltage B Grade A Grade Initial Accuracy B Grade B Grade A Grade A Grade Temperature Coefficient SOIC-8 (B Grade) SOIC-8 (A Grade) MSOP-8 Line Regulation Load Regulation Symbol VO VO VOERR VOERR VOERR VOERR TCVO -40C < TA < +125C -40C < TA < +125C -40C < TA < +125C VIN = 5 V to 18 V -40C < TA < +125C ILOAD = 0 mA to 10 mA, VIN = 6 V -40C < TA < +125C ILOAD = -10 mA to 0 mA, VIN = 6 V -40C < TA < +125C No load, -40C < TA < +125C 0.1 Hz to 10.0 Hz 1 kHz CIN = 0 1,000 h fIN = 10 kHz 5 2 1 2 2 5 Conditions Min 2.9985 2.996 Typ 3.000 3.000 Max 3.0015 3.004 1.5 0.05 4 0.13 3 10 10 20 15 15 800 Unit V V mV % mV % ppm/C ppm/C ppm/C ppm/V ppm/mA ppm/mA A V p-p nVHz s ppm ppm dB mA V V
VO/VIN VO/ILOAD
Quiescent Current Voltage Noise Voltage Noise Density Turn-On Settling Time Long-Term Stability1 Output Voltage Hysteresis Ripple Rejection Ratio Short Circuit to GND Supply Voltage Operating Range Supply Voltage Headroom
IIN eN p-p eN tR VO VO_HYS RRR ISC VIN VIN - VO
590 3.75 90 10 40 20 -70 40
18
1
The long-term stability specification is noncumulative. The drift in subsequent 1,000 hour periods is significantly lower than in the first 1,000 hour period.
Rev. B | Page 5 of 24
ADR430/ADR431/ADR433/ADR434/ADR435/ADR439
ADR434 ELECTRICAL CHARACTERISTICS
VIN = 6.1 V to 18 V, ILOAD = 0 mA, TA = 25C, unless otherwise noted. Table 5.
Parameter Output Voltage B Grade A Grade Initial Accuracy B Grade B Grade A Grade A Grade Temperature Coefficient SOIC-8 (B Grade) SOIC-8 (A Grade) MSOP-8 Line Regulation Load Regulation Symbol VO VO VOERR VOERR VOERR VOERR TCVO -40C < TA < +125C -40C < TA < +125C -40C < TA < +125C VIN = 6.1 V to 18 V -40C < TA < +125C ILOAD = 0 mA to 10 mA, VIN = 7 V -40C < TA < +125C ILOAD = -10 mA to 0 mA, VIN = 7 V -40C < TA < +125C No load, -40C < TA < +125C 0.1 Hz to 10.0 Hz 1 kHz CIN = 0 1,000 h fIN = 10 kHz 6.1 2 1 2 2 5 Conditions Min 4.0945 4.091 Typ 4.096 4.096 Max 4.0975 4.101 1.5 0.04 5 0.13 3 10 10 20 15 15 800 Unit V V mV % mV % ppm/C ppm/C ppm/C ppm/V ppm/mA ppm/mA A V p-p nVHz s ppm ppm dB mA V V
VO/VIN VO/ILOAD
Quiescent Current Voltage Noise Voltage Noise Density Turn-On Settling Time Long-Term Stability1 Output Voltage Hysteresis Ripple Rejection Ratio Short Circuit to GND Supply Voltage Operating Range Supply Voltage Headroom
IIN eN p-p eN tR VO VO_HYS RRR ISC VIN VIN - VO
595 6.25 100 10 40 20 -70 40
18
1
The long-term stability specification is noncumulative. The drift in subsequent 1,000 hour periods is significantly lower than in the first 1,000 hour period.
Rev. B | Page 6 of 24
ADR430/ADR431/ADR433/ADR434/ADR435/ADR439
ADR435 ELECTRICAL CHARACTERISTICS
VIN = 7 V to 18 V, ILOAD = 0 mA, TA = 25C, unless otherwise noted. Table 6.
Parameter Output Voltage B Grade A Grade Initial Accuracy B Grade B Grade A Grade A Grade Temperature Coefficient SOIC-8 (B Grade) SOIC-8 (A Grade) MSOP-8 Line Regulation Load Regulation Symbol VO VO VOERR VOERR VOERR VOERR TCVO -40C < TA < +125C -40C < TA < +125C -40C < TA < +125C VIN = 7 V to 18 V -40C < TA < +125C ILOAD = 0 mA to 10 mA, VIN = 8 V -40C < TA < +125C ILOAD = -10 mA to 0 mA, VIN = 8 V -40C < TA < +125C No load, -40C < TA < +125C 0.1 Hz to 10 Hz 1 kHz CIN = 0 1,000 h fIN = 10 kHz 7 2 1 2 2 5 Conditions Min 4.998 4.994 Typ 5.000 5.000 Max 5.002 5.006 2 0.04 6 0.12 3 10 10 20 15 15 800 Unit V V mV % mV % ppm/C ppm/C ppm/C ppm/V ppm/mA ppm/mA A V p-p nV/Hz s ppm ppm dB mA V V
VO/VIN VO/ILOAD
Quiescent Current Voltage Noise Voltage Noise Density Turn-On Settling Time Long-Term Stability1 Output Voltage Hysteresis Ripple Rejection Ratio Short Circuit to GND Supply Voltage Operating Range Supply Voltage Headroom
IIN eN p-p eN tR VO VO_HYS RRR ISC VIN VIN - VO
620 8 115 10 40 20 -70 40
18
1
The long-term stability specification is noncumulative. The drift in subsequent 1,000 hour periods is significantly lower than in the first 1,000 hour period.
Rev. B | Page 7 of 24
ADR430/ADR431/ADR433/ADR434/ADR435/ADR439
ADR439 ELECTRICAL CHARACTERISTICS
VIN = 6.5 V to 18 V, ILOAD = 0 mV, TA = 25C, unless otherwise noted. Table 7.
Parameter Output Voltage B Grade A Grade Initial Accuracy B Grade B Grade A Grade A Grade Temperature Coefficient SOIC-8 (B Grade) SOIC-8 (A Grade) MSOP-8 Line Regulation Load Regulation Symbol VO VO VOERR VOERR VOERR VOERR TCVO -40C < TA < +125C -40C < TA < +125C -40C < TA < +125C VIN = 6.5 V to 18 V -40C < TA < +125C ILOAD = 0 mA to 10 mA, VIN = 6.5 V -40C < TA < +125C ILOAD = -10 mA to 0 mA, VIN = 6.5 V -40C < TA < +125C No load, -40C < TA < +125C 0.1 Hz to 10.0 Hz 1 kHz CIN = 0 1,000 h fIN = 10 kHz 6.5 2 1 2 2 5 Conditions Min 4.498 4.4946 Typ 4.500 4.500 Max 4.502 4.5054 2 0.04 5.4 0.12 3 10 10 20 15 15 800 Unit V V mV % mV % ppm/C ppm/C ppm/C ppm/V ppm/mA ppm/mA A V p-p nV/Hz s ppm ppm dB mA V V
VO/VIN VO/ILOAD
Quiescent Current Voltage Noise Voltage Noise Density Turn-On Settling Time Long-Term Stability1 Output Voltage Hysteresis Ripple Rejection Ratio Short Circuit to GND Supply Voltage Operating Range Supply Voltage Headroom
IIN eN p-p eN tR VO VO_HYS RRR ISC VIN VIN - VO
600 7.5 110 10 40 20 -70 40
18
1
The long-term stability specification is noncumulative. The drift in subsequent 1,000 hour periods is significantly lower than in the first 1,000 hour period.
Rev. B | Page 8 of 24
ADR430/ADR431/ADR433/ADR434/ADR435/ADR439
ABSOLUTE MAXIMUM RATINGS
@ 25C, unless otherwise noted. Table 8.
Parameter Supply Voltage Output Short-Circuit Duration to GND Storage Temperature Range (R, RM Packages) Operating Temperature Range Junction Temperature Range Lead Temperature Range (Soldering, 60 s) Rating 20 V Indefinite -65C to +125C -40C to +125C -65C to +150C 300C
PACKAGE TYPE
Table 9.
Package Type 8-Lead SOIC (R) 8-Lead MSOP (RM) JA1 130 190 JC 43 Unit C/W C/W
1
JA is specified for worst-case conditions (device soldered in circuit board for surface-mount packages).
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 beyond those indicated in the operational sections of this specification is not implied. Absolute maximum ratings apply individually only, not in combination.
ESD 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 this product 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.
Rev. B | Page 9 of 24
ADR430/ADR431/ADR433/ADR434/ADR435/ADR439
TYPICAL PERFORMANCE CHARACTERISTICS
Default conditions: 5 V, CL = 5 pF, G = 2, Rg = Rf = 1 k, RL = 2 k, VO = 2 V p-p, Frequency = 1 MHz, TA = 25C.
0.8
2.5009 2.5007 2.5005 2.5003 2.5001 2.4999 2.4997 2.4995 -40
0.7
SUPPLY CURRENT (mA)
+125C
OUTPUT VOLTAGE (V)
0.6
+25C -40C
0.5
0.4
04500-0-015
-25
-10
5
20
35
50
65
80
95
110
125
4
6
8
10
12
14
16
TEMPERATURE (C)
INPUT VOLTAGE (V)
Figure 3. ADR431 VOUT vs. Temperature
4.0980
Figure 6. ADR435 Supply Current vs. Input Voltage
700
4.0975
650
SUPPLY CURRENT (A)
OUTPUT VOLTAGE (V)
4.0970
600
4.0965
550
4.0960
500
4.0955
450
04500-0-016
-25
-10
5
20
35
50
65
80
95
110
125
-25
-10
5
20
35
50
65
80
95
110
125
TEMPERATURE (C)
TEMPERATURE (C)
Figure 4. ADR434 VOUT vs. Temperature
5.0025 5.0020 5.0015 5.0010 5.0005 5.0000 4.9995 4.9990 -40
Figure 7. ADR435 Supply Current vs. Temperature
0.60 0.58 0.56 +125C
SUPPLY CURRENT (mA)
OUTPUT VOLTAGE (V)
0.54 0.52 0.50 0.48 0.46 0.44 0.42 -40C +25C
04500-0-017
-25
-10
5
20
35
50
65
80
95
110
125
6
8
10
12
14
16
18
TEMPERATURE (C)
INPUT VOLTAGE (V)
Figure 5. ADR435 VOUT vs. Temperature
Rev. B | Page 10 of 24
Figure 8. ADR431 Supply Current vs. Input Voltage
04500-0-020
0.40
04500-0-019
4.0950 -40
400 -40
04500-0-018
0.3
ADR430/ADR431/ADR433/ADR434/ADR435/ADR439
610 580
2.5
SUPPLY CURRENT (A)
550 520 490 460 430 400 -40
DIFFERENTIAL VOLTAGE (V)
2.0 -40C 1.5 +25C 1.0
+125C
0.5
04500-0-021
-25
-10
5
20
35
50
65
80
95
110
125
-5
0 LOAD CURRENT (mA)
5
10
TEMPERATURE (C)
Figure 9. ADR431 Supply Current vs. Temperature
Figure 12. ADR431 Minimum Input/Output Differential Voltage vs. Load Current
1.9 NO LOAD 1.8
15
IL = 0mA to 10mA
LOAD REGULATION (ppm/mA)
12
MINIMUM HEADROOM (V)
1.7 1.6 1.5 1.4 1.3 1.2 1.1
9
6
3
04500-0-022
-25
-10
5
20
35
50
65
80
95
110
125
-25
-10
5
20
35
50
65
80
95
110
125
TEMPERATURE (C)
TEMPERATURE (C)
Figure 10. ADR431 Load Regulation vs. Temperature
15
2.5
Figure 13. ADR431 Minimum Headroom vs. Temperature
IL = 0mA to 10mA
LOAD REGULATION (ppm/mA)
DIFFERENTIAL VOLTAGE (V)
12
2.0 -40C 1.5 +25C 1.0 +125C 0.5
9
6
3
04500-0-023
-25
-10
5
20
35
50
65
80
95
110
125
-5
0 LOAD CURRENT (mA)
5
10
TEMPERATURE (C)
Figure 11. ADR435 Load Regulation vs. Temperature
Figure 14. ADR435 Minimum Input/Output Differential Voltage vs. Load Current
Rev. B | Page 11 of 24
04500-0-026
0 -40
0 -10
04500-0-025
0 -40
1.0 -40
04500-0-024
0 -10
ADR430/ADR431/ADR433/ADR434/ADR435/ADR439
1.9 NO LOAD 1.7
CLOAD = 0.01F NO INPUT CAPACITOR VOUT = 1V/DIV
MINIMUM HEADROOM (V)
1.5
1.3
VIN = 2V/DIV
1.1
TIME = 4s/DIV
0.9 -40
-25
-10
5
20
35
50
65
80
95
110
125
TEMPERATURE (C)
04500-0-027
Figure 15. ADR435 Minimum Headroom vs. Temperature
Figure 18. ADR431 Turn-On Response, 0.01 F Load Capacitor
20 VIN = 7V TO 18V 16
VOUT = 1V/DIV
CIN = 0.01F NO LOAD
LINE REGULATION (ppm/V)
12
8
4
VIN = 2V/DIV
TIME = 4s/DIV
-25
-10
5
20
35
50
65
80
95
110
125
TEMPERATURE (C)
04500-0-028
-4 -40
Figure 16. ADR435 Line Regulation vs. Temperature
Figure 19. ADR431 Turn-Off Response
CIN = 0.01F NO LOAD VOUT = 1V/DIV
BYPASS CAPACITOR = 0F
LINE INTERRUPTION
500mV/DIV VIN
VOUT = 50mV/DIV VIN = 2V/DIV
04500-0-030
TIME = 4s/DIV
TIME = 100s/DIV
Figure 17. ADR431 Turn-On Response
Figure 20. ADR431 Line Transient Response--No Capacitors
Rev. B | Page 12 of 24
04500-0-033
04500-0-032
0
04500-0-031
ADR430/ADR431/ADR433/ADR434/ADR435/ADR439
BYPASS CAPACITOR = 0.1F LINE INTERRUPTION 500mV/DIV VIN
VOUT = 50mV/DIV 2V/DIV
04500-0-034
TIME = 100s/DIV
TIME = 1s/DIV
Figure 21. ADR431 Line Transient Response--0.1 F Bypass Capacitor
Figure 24. ADR435 0.1 Hz to 10.0 Hz Voltage Noise
1V/DIV
50V/DIV
04500-0-035
TIME = 1s/DIV
Figure 22. ADR431 0.1 Hz to 10.0 Hz Voltage Noise
Figure 25. ADR435 10 Hz to 10 kHz Voltage Noise
14 12 10 8 6 4 2 0 -120 -90
50V/DIV
04500-0-036
TIME = 1s/DIV
NUMBER OF PARTS
04500-0-038
TIME = 1s/DIV
04500-0-037
-70
-50
-30
-10
10
30
50
70
90
120
DEVIATION (PPM)
Figure 23. ADR431 10 Hz to 10 kHz Voltage Noise
Figure 26. ADR431 Typical Hysteresis
Rev. B | Page 13 of 24
04500-0-029
ADR430/ADR431/ADR433/ADR434/ADR435/ADR439
50 45 40
10 -10 -30 -50 -70 -90 -110 -130
04500-0-039
04500-0-040
OUTPUT IMPEDANCE ()
35 30 25 20 15 10 5 0 100 1k 10k FREQUENCY (Hz) ADR430 ADR435
ADR433
RIPPLE REJECTION (dB)
100k
-150 10
100
1k
10k
100k
1M
FREQUENCY (Hz)
Figure 27. Output Impedance vs. Frequency
Figure 28. Ripple Rejection Ratio
Rev. B | Page 14 of 24
ADR430/ADR431/ADR433/ADR434/ADR435/ADR439
THEORY OF OPERATION
The ADR43x series of references uses a new reference generation technique known as XFET (eXtra implanted junction FET). This technique yields a reference with low supply current, good thermal hysteresis, and exceptionally low noise. The core of the XFET reference consists of two junction field-effect transistors (JFETs), one of which has an extra channel implant to raise its pinch-off voltage. By running the two JFETs at the same drain current, the difference in pinch-off voltage can be amplified and used to form a highly stable voltage reference. The intrinsic reference voltage is around 0.5 V with a negative temperature coefficient of about -120 ppm/C. This slope is essentially constant to the dielectric constant of silicon and can be closely compensated by adding a correction term generated in the same fashion as the proportional-to-temperature (PTAT) term used to compensate band gap references. The big advantage of an XFET reference is that the correction term is some 30 times lower (therefore, requiring less correction) than for a band gap reference, resulting in much lower noise, because most of the noise of a band gap reference comes from the temperature compensation circuitry. Figure 29 shows the basic topology of the ADR43x series. The temperature correction term is provided by a current source with a value designed to be proportional to absolute temperature. The general equation is
VOUT = G x (VP - R1 x I PTAT
The ADR43x family of references is guaranteed to deliver load currents to 10 mA with an input voltage that ranges from 4.5 V to 18 V. When these devices are used in applications at higher currents, users should use the following equation to account for the temperature effects due to the power dissipation increases.
TJ = PD x JA + TA
where: TJ and TA are the junction and ambient temperatures, respectively. PD is the device power dissipation. JA is the device package thermal resistance.
(2)
BASIC VOLTAGE REFERENCE CONNECTIONS
Voltage references, in general, require a bypass capacitor connected from VOUT to GND. The circuit in Figure 30 illustrates the basic configuration for the ADR43x family of references. Other than a 0.1 F capacitor at the output to help improve noise suppression, a large output capacitor at the output is not required for circuit stability.
TP 1 VIN 10F + 0.1F
2 8
TP NIC OUTPUT TRIM 0.1F
04500-0-003
ADR43x
7
6 NIC 3 TOP VIEW (Not to Scale) 4 5
)
(1)
NIC = NO INTERNAL CONNECTION TP = TEST PIN (DO NOT CONNECT)
where: G is the gain of the reciprocal of the divider ratio. VP is the difference in pinch-off voltage between the two JFETs. IPTAT is the positive temperature coefficient correction current. ADR43x devices are created by on-chip adjustment of R2 and R3 to achieve 2.048 V or 2.500 V, respectively, at the reference output.
I1 IPTAT I1
VIN
Figure 30. Basic Voltage Reference Configuration
NOISE PERFORMANCE
The noise generated by the ADR43x family of references is typically less than 3.75 V p-p over the 0.1 Hz to 10.0 Hz band for ADR430, ADR431, and ADR433. Figure 22 shows the 0.1 Hz to 10 Hz noise of the ADR431, which is only 3.5 V p-p. The noise measurement is made with a band-pass filter made of a 2-pole high-pass filter with a corner frequency at 0.1 Hz and a 2-pole low-pass filter with a corner frequency at 10.0 Hz.
ADR43x
VOUT R2
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 17 and Figure 18 show the turn-on settling time for the ADR431.
* VP
R1 R3
04500-0-002
*EXTRA CHANNEL IMPLANT VOUT = G(VP - R1 x IPTAT)
GND
Figure 29. Simplified Schematic Device Power Dissipation Considerations
Rev. B | Page 15 of 24
ADR430/ADR431/ADR433/ADR434/ADR435/ADR439
APPLICATIONS
OUTPUT ADJUSTMENT
The ADR43x trim terminal can be used to adjust the output voltage over a 0.5% range. This feature allows the system designer to trim system errors out by setting the reference to a voltage other than the nominal. This is also helpful if the part is used in a system at temperature to trim out any error. Adjustment of the output has negligible effect on the temperature performance of the device. To avoid degrading temperature coefficients, both the trimming potentiometer and the two resistors need to be low temperature coefficient types, preferably <100 ppm/C.
INPUT
SOURCE FIBER GIMBAL + SENSOR LASER BEAM ACTIVATOR LEFT DESTINATION FIBER ACTIVATOR RIGHT
MEMS MIRROR
AMPL
PREAMP
AMPL
ADR431 CONTROL ELECTRONICS DAC ADC DAC ADR431 ADR431
04500-0-005
VIN VO
OUTPUT VO = 0.5% R1 470k
DSP GND
ADR43x
TRIM GND
Figure 32. All-Optical Router Network
RP 10k
04500-0-004
R2
10k (ADR420) 15k (ADR421)
NEGATIVE PRECISION REFERENCE WITHOUT PRECISION RESISTORS
In many current-output CMOS DAC applications where the output signal voltage must be of the same polarity as the reference voltage, it is often required to reconfigure a currentswitching DAC into a voltage-switching DAC through the use of a 1.25 V reference, an op amp, and a pair of resistors. Using a current-switching DAC directly requires an additional operational amplifier at the output to re-invert the signal. A negative voltage reference is then desirable from the standpoint that an additional operational amplifier is not required for either re-inversion (current-switching mode) or amplification (voltage-switching mode) of the DAC output voltage. In general, any positive voltage reference can be converted into a negative voltage reference through the use of an operational amplifier and a pair of matched resistors in an inverting configuration. The disadvantage to this approach is that the largest single source of error in the circuit is the relative matching of the resistors used. A negative reference can easily be generated by adding a precision op amp and configuring it as shown in Figure 33. VOUT is at virtual ground and, therefore, the negative reference can be taken directly from the output of the op amp. The op amp must be dual supply, have low offset and rail-to-rail capability, if negative supply voltage is close to the reference output.
Figure 31. Output Trim Adjustment
REFERENCE FOR CONVERTERS IN OPTICAL NETWORK CONTROL CIRCUITS
In the upcoming high capacity, all-optical router network, Figure 32 employs arrays of micromirrors to direct and route optical signals from fiber to fiber without first converting them to electrical form, which reduces the communication speed. The tiny micromechanical mirrors are positioned so that each is illuminated by a single wavelength that carries unique information and can be passed to any desired input and output fiber. The mirrors are tilted by the dual-axis actuators controlled by precision ADCs and DACs within the system. Due to the microscopic movement of the mirrors, not only is the precision of the converters important, but the noise associated with these controlling converters is also extremely critical, because total noise within the system can be multiplied by the number of converters employed. As a result, to maintain the stability of the control loop for this application, the ADR43x is necessary due to its exceptionally low noise.
Rev. B | Page 16 of 24
ADR430/ADR431/ADR433/ADR434/ADR435/ADR439
+VDD
VIN 2 RLW VIN A1 VOUT 6 GND 4
+
2 VIN 6 VOUT
VOUT SENSE RLW VOUT FORCE RL
ADR43x
GND 4 A1
-VREF
04500-0-006
A1 = OP191
Figure 35. Advantage of Kelvin Connection
DUAL POLARITY REFERENCES
Dual polarity references can easily be made with an op amp and a pair of resistors. In order not to defeat the accuracy obtained by ADR43x, it is imperative to match the resistance tolerance as well as the temperature coefficient of all the components.
VIN 1F 0.1F
2
-VDD
A1 = OP777, OP193
Figure 33. Negative Reference
HIGH VOLTAGE FLOATING CURRENT SOURCE
The circuit in Figure 34 can be used to generate a floating current source with minimal self-heating. This particular configuration can operate on high supply voltages determined by the breakdown voltage of the N-channel JFET.
+VS SST111 VISHAY
VIN
VOUT 6 R1 10k +10V TRIM 5 V+ R2 10k
04500-0-008
ADR43x
+5V
ADR435
U1 GND
4
OP1177
VIN
U2 V-
-5V
04500-0-009
ADR43x
VOUT OP90 GND RL 2.1k
-VS
R3 5k
-10V
2N3904
Figure 36. +5 V and -5 V References Using ADR435
+2.5V
04500-0-007
+10V
2
VIN U1
VOUT 6 R1 5.6k
Figure 34. High Voltage Floating Current Source
ADR435
GND
4
KELVIN CONNECTIONS
In many portable instrumentation applications where PC board cost and area go hand-in-hand, circuit interconnects are very often of dimensionally minimum width. These narrow lines can cause large voltage drops if the voltage reference is required to provide load currents to various functions. In fact, a circuit's interconnects can exhibit a typical line resistance of 0.45 m/ square (1 oz. Cu, for example). Force and sense connections, also referred to as Kelvin connections, offer a convenient method of eliminating the effects of voltage drops in circuit wires. Load currents flowing through wiring resistance produce an error (VERROR = R x IL) at the load. However, the Kelvin connection of Figure 35 overcomes the problem by including the wiring resistance within the forcing loop of the op amp. Because the op amp senses the load voltage, the op amp loop control forces the output to compensate for the wiring error and to produce the correct voltage at the load.
TRIM 5 R2 5.6k V+
OP1177
-2.5V
04500-0-010
U2 V-
-10V
Figure 37. +2.5 V and -2.5 V References Using ADR435
Rev. B | Page 17 of 24
ADR430/ADR431/ADR433/ADR434/ADR435/ADR439
PROGRAMMABLE CURRENT SOURCE
Together with a digital potentiometer and a Howland current pump, ADR435 forms the reference source for a programmable current as
R2A + R2 B R1 IL = R2 B x VW
PROGRAMMABLE DAC REFERENCE VOLTAGE
With a multichannel DAC such as a quad 12-bit voltage output DAC AD7398, one of its internal DACs and an ADR43x voltage reference can be used as a common programmable VREFX for the rest of the DACs. The circuit configuration is shown in Figure 39.
R2 0.1% VREF VIN
(3)
VREFA DAC A VOUTA R1 0.1%
and
ADR436
VW =
D xVREF 2N
(4)
VREFB DAC B
VOUTB
VOB = VREFX (DB)
where: D is the decimal equivalent of the input code. N is the number of bits. In addition, R1 and R2 must be equal to R1 and R2A + R2B, respectively. R2B in theory can be made as small as needed to achieve the necessary current within the A2 output current driving capability. In this example, OP2177 can deliver a maximum of 10 mA. Because the current pump employs both positive and negative feedback, capacitors C1 and C2 are needed to ensure that the negative feedback prevails and, therefore, avoids oscillation. This circuit also allows bidirectional current flow if the inputs VA and VB of the digital potentiometer are supplied with the dual polarity references, as shown previously.
C1 10pF VDD
2
VREFC DAC C
VOUTC
VOC = VREFX (DC)
VREFD DAC D
VOUTD
VOD = VREFX (DD)
04500-0-012
AD7398
Figure 39. Programmable DAC Reference
The relationship of VREFX to VREF depends on the digital code and the ratio of R1 and R2, and is given by
R2 VREF x 1 + R1 = 1 + D x R2 2 N R1
R1' 50k
R2' 1k VDD
VREFX
(5)
VIN
TRIM 5 U1
ADR435
GND
4
AD5232 U2 DIGITAL POTENTIOMETER A U2 B W
V+ VDD V+ C2 10pF R1 50k
OP2177
A2 V- R2B 10
VOUT 6
OP2177
A1 V-
VSS R2A 1k LOAD
04500-0-011
where: D is the decimal equivalent of input code. N is the number of bits. VREF is the applied external reference. VREFX is the reference voltage for DAC A to DAC D.
Table 10. VREFX vs. R1 and R2
R1, R2 R1 = R2 R1 = R2 R1 = R2 R1 = 3R2 R1 = 3R2 R1 = 3R2 Digital Code 0000 0000 0000 1000 0000 0000 1111 1111 1111 0000 0000 0000 1000 0000 0000 1111 1111 1111 VREF 2 VREF 1.3 VREF VREF 4 VREF 1.6 VREF VREF
VSS
+ VL -
GND
IL
Figure 38. Programmable Current Source
Rev. B | Page 18 of 24
ADR430/ADR431/ADR433/ADR434/ADR435/ADR439
PRECISION VOLTAGE REFERENCE FOR DATA CONVERTERS
The ADR43x family has a number of features that make it ideal for use with ADCs and DACs. The exceptional low noise, tight temperature coefficient, and high accuracy characteristics make the ADR43x ideal for low noise applications such as cellular base station applications. Another example of ADC for which the ADR431 is well suited is the AD7701. Figure 40 shows the ADR431 used as the precision reference for this converter. The AD7701 is a 16-bit ADC with on-chip digital filtering intended for the measurement of wide dynamic range and low frequency signals such as those representing chemical, physical, or biological processes. It contains a charge-balancing (-) ADC, a calibration microcontroller with on-chip static RAM, a clock oscillator, and a serial communications port.
+5V ANALOG SUPPLY 0.1F 10F AVDD VIN VOUT 0.1F VREF
PRECISION BOOSTED OUTPUT REGULATOR
A precision voltage output with boosted current capability can be realized with the circuit shown in Figure 41. In this circuit, U2 forces VO to be equal to VREF by regulating the turn on of N1. Therefore, the load current is furnished by VIN. In this configuration, a 50 mA load is achievable at VIN of 5 V. Moderate heat is generated on the MOSFET, and higher current can be achieved with a replacement of the larger device. In addition, for a heavy capacitive load with step input, a buffer may be added at the output to enhance the transient response.
N1 VIN 5V 2 U1 VIN VOUT TRIM GND 2N7002 6 5
+ V+
VO RL 25
AD8601
- V-
DVDD SLEEP MODE DRDV CS SCLK SDATA DATA READY READ (TRANSMIT) SERIAL CLOCK SERIAL CLOCK 0.1F
Figure 41. Precision Boosted Output Regulator
ADR431
GND
RANGES SELECT CALIBRATE ANALOG INPUT ANALOG GROUND 0.1F
BP/UP CAL AIN AGND AVSS
CLKIN CLKOUT SC1 SC2 DGND 0.1F DVSS
Figure 40. Voltage Reference for 16-Bit ADC AD7701
Rev. B | Page 19 of 24
04500-0-013
-5V ANALOG SUPPLY
0.1F
10F
04500-0-014
AD7701
4
U2
ADR431
ADR430/ADR431/ADR433/ADR434/ADR435/ADR439
OUTLINE DIMENSIONS
3.00 BSC
8
5
3.00 BSC
4
4.90 BSC
PIN 1 0.65 BSC 0.15 0.00 0.38 0.22 COPLANARITY 0.10 1.10 MAX 8 0 0.80 0.60 0.40
0.23 0.08 SEATING PLANE
COMPLIANT TO JEDEC STANDARDS MO-187AA
Figure 42. 8-Lead Mini Small Outline Package [MSOP] (RM-8) Dimensions shown in millimeters
5.00 (0.1968) 4.80 (0.1890)
8 5 4
4.00 (0.1574) 3.80 (0.1497) 1
6.20 (0.2440) 5.80 (0.2284)
1.27 (0.0500) BSC 0.25 (0.0098) 0.10 (0.0040)
1.75 (0.0688) 1.35 (0.0532)
0.50 (0.0196) x 45 0.25 (0.0099)
0.51 (0.0201) COPLANARITY SEATING 0.31 (0.0122) 0.10 PLANE
8 0.25 (0.0098) 0 1.27 (0.0500) 0.40 (0.0157) 0.17 (0.0067)
COMPLIANT TO JEDEC STANDARDS MS-012AA CONTROLLING DIMENSIONS ARE IN MILLIMETERS; INCH DIMENSIONS (IN PARENTHESES) ARE ROUNDED-OFF MILLIMETER EQUIVALENTS FOR REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN
Figure 43. 8-Lead Standard Small Outline Package [SOIC] Narrow Body (R-8) Dimensions shown in millimeters and (inches)
Rev. B | Page 20 of 24
ADR430/ADR431/ADR433/ADR434/ADR435/ADR439
ORDERING GUIDE
Initial Accuracy Model ADR430AR ADR430AR-REEL7 ADR430ARM ADR430ARM-REEL7 ADR430BR ADR430BR-REEL7 ADR431AR ADR431AR-REEL7 ADR431ARM ADR431ARM-REEL7 ADR431BR ADR431BR-REEL7 ADR433AR ADR433AR-REEL7 ADR433ARM ADR433ARM-REEL7 ADR433BR ADR433BR-REEL7 ADR434AR ADR434AR-REEL7 ADR434ARM ADR434ARM-REEL7 ADR434BR ADR434BR-REEL7 ADR435AR ADR435AR-REEL7 ADR435ARM ADR435ARM-REEL7 ADR435BR ADR435BR-REEL7 ADR439AR ADR439AR-REEL7 ADR439ARM ADR439ARM-REEL7 ADR439BR ADR439BR-REEL7 Output Voltage (VO) 2.048 2.048 2.048 2.048 2.048 2.048 2.500 2.500 2.500 2.500 2.500 2.500 3.000 3.000 3.000 3.000 3.000 3.000 4.096 4.096 4.096 4.096 4.096 4.096 5.000 5.000 5.000 5.000 5.000 5.000 4.500 4.500 4.500 4.500 4.500 4.500 mV 3 3 3 3 1 1 3 3 3 3 1 1 4 4 4 4 1.5 1.5 5 5 5 5 1.5 1.5 6 6 6 6 2 2 5.4 5.4 5.4 5.4 2 2 (%) 0.15 0.15 0.15 0.15 0.05 0.05 0.12 0.12 0.12 0.12 0.04 0.04 0.12 0.12 0.12 0.12 0.05 0.05 0.13 0.13 0.13 0.13 0.04 0.04 0.12 0.12 0.12 0.12 0.04 0.04 0.12 0.12 0.12 0.12 0.04 0.04 Temperature Coefficient Package (ppm/C) 10 10 10 10 3 3 10 10 10 10 3 3 10 10 10 10 3 3 10 10 10 10 3 3 10 10 10 10 3 3 10 10 10 10 3 3 Package Description 8-lead SOIC 8-Lead SOIC 8-Lead MSOP 8-Lead MSOP 8-lead SOIC 8-Lead SOIC 8-Lead SOIC 8-Lead SOIC 8-Lead MSOP 8-Lead MSOP 8-Lead SOIC 8-Lead SOIC 8-Lead SOIC 8-Lead SOIC 8-Lead MSOP 8-Lead MSOP 8-Lead SOIC 8-Lead SOIC 8-Lead SOIC 8-Lead SOIC 8-Lead MSOP 8-Lead MSOP 8-Lead SOIC 8-Lead SOIC 8-Lead SOIC 8-Lead SOIC 8-Lead MSOP 8-Lead MSOP 8-Lead SOIC 8-Lead SOIC 8-Lead SOIC 8-Lead SOIC 8-Lead MSOP 8-Lead MSOP 8-Lead SOIC 8-Lead SOIC Parts per Reel N/A 3,000 N/A 1,000 N/A 3,000 N/A 3,000 N/A 1,000 N/A 3,000 N/A 3,000 N/A 1,000 N/A 3,000 N/A 3,000 N/A 1,000 N/A 3,000 N/A 3,000 N/A 1,000 N/A 3,000 N/A 3,000 N/A 1,000 N/A 3,000 Temperature Range -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C
Branding
RHA RHA
RJA RJA
RKA RKA
RLA RLA
RMA RMA
RNA RNA
Rev. B | Page 21 of 24
ADR430/ADR431/ADR433/ADR434/ADR435/ADR439
NOTES
Rev. B | Page 22 of 24
ADR430/ADR431/ADR433/ADR434/ADR435/ADR439
NOTES
Rev. B | Page 23 of 24
ADR430/ADR431/ADR433/ADR434/ADR435/ADR439
NOTES
(c) 2004 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D04500-0-9/04(B)
Rev. B | Page 24 of 24

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