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Micropower, High Accuracy Voltage References
ADR3412/ADR3420/ADR3425/ADR3430/ADR3433/ADR3440/ADR3450
FEATURES
Initial accuracy: 0.1% (maximum) Maximum temperature coefficient: 8 ppm/C Operating temperature range: -40C to +125C Output current: +10 mA source/-3 mA sink Low quiescent current: 100 A (maximum) Low dropout voltage: 250 mV at 2 mA Output noise (0.1 Hz to 10 Hz): <10 V p-p at 1.2 V (typical) 6-lead SOT-23
PIN CONFIGURATION
GND FORCE 1
6
VOUT FORCE VOUT SENSE
08440-001
ADR34xx
GND SENSE 2
5
TOP VIEW ENABLE 3 (Not to Scale) 4 VIN
Figure 1. 6-Lead SOT-23
APPLICATIONS
Precision data acquisition systems Industrial instrumentation Medical devices Battery-powered devices
GENERAL DESCRIPTION
The ADR3412/ADR3420/ADR3425/ADR3430/ADR3433/ ADR3440/ADR3450 are low cost, low power, high precision CMOS voltage references, featuring 0.1% initial accuracy, low operating current, and low output noise in a small SOT-23 package. For high accuracy, output voltage and temperature coefficient are trimmed digitally during final assembly using Analog Devices, Inc., patented DigiTrim(R) technology. Stability and system reliability are further improved by the low output voltage hysteresis of the device and low long-term output voltage drift. Furthermore, the low operating current of the device (100 A maximum) facilitates usage in low power devices, and its low output noise helps maintain signal integrity in critical signal processing systems. These CMOS are available in a wide range of output voltages, all of which are specified over the industrial temperature range of -40C to +125C. Table 1. Selection Guide
Model ADR3412 ADR3420 ADR3425 ADR3430 ADR3433 ADR3440 ADR3450 Output Voltage (V) 1.200 2.048 2.500 3.000 3.300 4.096 5.000 Input Voltage Range (V) 2.3 to 5.5 2.3 to 5.5 2.7 to 5.5 3.2 to 5.5 3.5 to 5.5 4.3 to 5.5 5.2 to 5.5
Table 2. Voltage Reference Choices from Analog Devices
VOUT (V) 0.5/1.0 1.2 2.048 2.5 Low Cost/ Low Power ADR3412 ADR280 ADR360 ADR3420 ADR3425 AD1582 ADR361 ADR3430 AD1583 ADR363 ADR366 ADR3433 ADR3440 AD1584 ADR364 ADR3450 AD1585 ADR365 Ultralow Power Low Noise ADR130 High Voltage, High Performance
REF191 ADR291 REF192 REF193
ADR430 ADR440 ADR431 ADR441 ADR433 ADR443
ADR03 AD780 ADR06 AD780
3.0
3.3 4.096
REF196 ADR292 REF198 ADR293 REF195 ADR434 ADR444 ADR435 ADR445
5.0
ADR02 AD586 ADR01 AD587
10.0
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.
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ADR3412/ADR3420/ADR3425/ADR3430/ADR3433/ADR3440/ADR3450 TABLE OF CONTENTS
Features .............................................................................................. 1 Applications ....................................................................................... 1 Pin Configuration ............................................................................. 1 General Description ......................................................................... 1 Revision History ............................................................................... 2 Specifications..................................................................................... 3 ADR3412 Electrical Characteristics .......................................... 3 ADR3420 Electrical Characteristics .......................................... 4 ADR3425 Electrical Characteristics .......................................... 5 ADR3430 Electrical Characteristics .......................................... 6 ADR3433 Electrical Characteristics .......................................... 7 ADR3440 Electrical Characteristics .......................................... 8 ADR3450 Electrical Characteristics .......................................... 9 Absolute Maximum Ratings and Minimum Operating Condition ......................................................................................... 10 Thermal Resistance .................................................................... 10 ESD Caution................................................................................ 10 Pin Configuration and Function Descriptions........................... 11 Typical Performance Characteristics ........................................... 12 Terminology .................................................................................... 18 Theory of Operation ...................................................................... 19 Power Dissipation....................................................................... 19 Applications Information .............................................................. 20 Basic Voltage Reference Connection ....................................... 20 Input and Output Capacitors .................................................... 20 4-Wire Kelvin Connections ...................................................... 20 VIN Slew Rate Considerations ................................................... 20 Shutdown/Enable Feature ......................................................... 20 Sample Applications ................................................................... 21 Outline Dimensions ....................................................................... 22 Ordering Guide .......................................................................... 22
REVISION HISTORY
6/10--Rev. A to Rev. B Added ADR3412, ADR3420, ADR3433 ..................... Throughout Changes to Table 1 and Table 2 ....................................................... 1 Added ADR3412 Electrical Characteristics Section and Table 3 ......................................................................................... 3 Added ADR3420 Electrical Characteristics Section and Table 4 ......................................................................................... 4 Added ADR3433 Electrical Characteristics Section and Table 7, Renumbered Subsequent Tables ...................................... 7 Replaced Figure 5 Through Figure 7 ........................................... 12 Replaced Figure 11 Through Figure 13 ....................................... 13 4/10--Rev. 0 to Rev. A Added ADR3430 and ADR3440 ....................................... Universal Changes to Table 1, Table 2, and Figure 1 ..................................... 1 Changes to Table 3 ............................................................................ 3 Added ADR3430 Electrical Characteristics Section .....................4 Added Table 4; Renumbered Sequentially .....................................4 Added ADR3440 Electrical Characteristics Section and Table 5 .................................................................................................5 Changes to Table 6.............................................................................6 Changes to Figure 2 ...........................................................................8 Changes to Figure 4 and Figure 5 ....................................................9 Changes to Figure 11...................................................................... 10 Changes to Figure 36 and Figure 37 Caption ............................. 14 Changes to Figure 39 and Theory of Operation Section .......... 16 Changes to Figure 40 and Figure 41............................................. 17 Changes to Negative Reference Section, Boosted Output Current Reference Section, Figure 43, and Figure 44 ................ 18 Changes to Ordering Guide .......................................................... 19 3/10--Revision 0: Initial Version
Rev. B | Page 2 of 24
ADR3412/ADR3420/ADR3425/ADR3430/ADR3433/ADR3440/ADR3450 SPECIFICATIONS
ADR3412 ELECTRICAL CHARACTERISTICS
VIN = 2.3 V to 5.5 V, TA = 25C, ILOAD = 0 mA, unless otherwise noted. Table 3.
Parameter OUTPUT VOLTAGE INITIAL ACCURACY TEMPERATURE COEFFICIENT LINE REGULATION LOAD REGULATION Sourcing Sinking OUTPUT CURRENT CAPACITY Sourcing Sinking QUIESCENT CURRENT Normal Operation Shutdown DROPOUT VOLTAGE 1 ENABLE PIN Shutdown Voltage ENABLE Voltage ENABLE Pin Leakage Current OUTPUT VOLTAGE NOISE OUTPUT VOLTAGE NOISE DENSITY OUTPUT VOLTAGE HYSTERESIS 2 RIPPLE REJECTION RATIO LONG-TERM STABILITY TURN-ON SETTLING TIME
1 2
Symbol VOUT VOERR TCVOUT VO/VIN VO/IL
Conditions
Min 1.1988
Typ 1.2000
-40C TA +125C VIN = 2.3 V to 5.5 V VIN = 2.3 V to 5.5 V, -40C TA +125C IL = 0 mA to 10 mA, VIN = 2.8 V, -40C TA +125C IL = 0 mA to -3 mA, VIN = 2.8 V, -40C TA +125C
7
Max 1.2012 0.1 1.2 8 50 160 30 50
Unit V % mV ppm/C ppm/V ppm/V ppm/mA ppm/mA
14 7
IL VIN = 2.8 V to 5.5 V VIN = 2.8 V to 5.5 V IQ ENABLE > VIN x 0.85 ENABLE = VIN, -40C TA +125C ENABLE < 0.7 V IL = 0 mA, -40C TA +125C IL = 2 mA, -40C TA +125C 0 VIN x 0.85 ENABLE = VIN, -40C TA +125C f = 0.1 Hz to 10 Hz f = 10 Hz to 10 kHz f = 1 kHz TA = +25C to -40C to +125C to +25C fIN = 60 Hz 1000 hours at 50C CIN = 0.1 F, CL = 0.1 F, RLoad = 1 k 0.85 8 28 0.6 70 -60 30 100 85 100 5 1.1 1.15 0.7 VIN 3 A A A V V V V A V p-p V rms V/Hz ppm dB ppm s 10 -3 mA mA
VDO
1 1
VL VH IEN en p-p en VOUT_HYS RRR VOUT_LTD tR
Refers to the minimum difference between VIN and VOUT such that VOUT maintains a minimum accuracy of 0.1%. See the Terminology section. See the Terminology section. The part is placed through the temperature cycle in the order of temperatures shown.
Rev. B | Page 3 of 24
ADR3412/ADR3420/ADR3425/ADR3430/ADR3433/ADR3440/ADR3450
ADR3420 ELECTRICAL CHARACTERISTICS
VIN = 2.3 V to 5.5 V, TA = 25C, ILOAD = 0 mA, unless otherwise noted. Table 4.
Parameter OUTPUT VOLTAGE INITIAL ACCURACY TEMPERATURE COEFFICIENT LINE REGULATION LOAD REGULATION Sourcing Sinking OUTPUT CURRENT CAPACITY Sourcing Sinking QUIESCENT CURRENT Normal Operation Shutdown DROPOUT VOLTAGE 1 ENABLE PIN Shutdown Voltage ENABLE Voltage ENABLE Pin Leakage Current OUTPUT VOLTAGE NOISE OUTPUT VOLTAGE NOISE DENSITY OUTPUT VOLTAGE HYSTERESIS 2 RIPPLE REJECTION RATIO LONG-TERM STABILITY TURN-ON SETTLING TIME
1 2
Symbol VOUT VOERR TCVOUT VO/VIN VO/IL
Conditions
Min 2.0459
Typ 2.0480
-40C TA +125C VIN = 2.3 V to 5.5 V VIN = 2.3 V to 5.5 V, -40C TA +125C IL = 0 mA to 10 mA, VIN = 2.8 V, -40C TA +125C IL = 0 mA to -3 mA, VIN = 2.8 V, -40C TA +125C
7
Max 2.0500 0.1 2.048 8 50 160 30 50
Unit V % mV ppm/C ppm/V ppm/V ppm/mA ppm/mA
12 7
IL VIN = 2.8 V to 5.5 V VIN = 2.8 V to 5.5 V IQ ENABLE > VIN x 0.85 ENABLE = VIN, -40C TA +125C ENABLE < 0.7 V IL = 0 mA, -40C TA +125C IL = 2 mA, -40C TA +125C 0 VIN x 0.85 ENABLE = VIN, -40C TA +125C f = 0.1 Hz to 10 Hz f = 10 Hz to 10 kHz f = 1 kHz TA = +25C to -40C to +125C to +25C fIN = 60 Hz 1000 hours at 50C CIN = 0.1 F, CL = 0.1 F, RLoad = 1 k 0.85 15 38 0.9 70 -60 30 400 85 100 5 250 300 0.7 VIN 3 A A A mV mV V V A V p-p V rms V/Hz ppm dB ppm s 10 -3 mA mA
VDO
100 150
VL VH IEN en p-p en VOUT_HYS RRR VOUT_LTD tR
Refers to the minimum difference between VIN and VOUT such that VOUT maintains a minimum accuracy of 0.1%. See the Terminology section. See the Terminology section. The part is placed through the temperature cycle in the order of temperatures shown.
Rev. B | Page 4 of 24
ADR3412/ADR3420/ADR3425/ADR3430/ADR3433/ADR3440/ADR3450
ADR3425 ELECTRICAL CHARACTERISTICS
VIN = 2.7 V to 5.5 V, IL = 0 mA, TA = 25C, unless otherwise noted. Table 5.
Parameter OUTPUT VOLTAGE INITIAL ACCURACY TEMPERATURE COEFFICIENT LINE REGULATION LOAD REGULATION Sourcing Sinking OUTPUT CURRENT CAPACITY Sourcing Sinking QUIESCENT CURRENT Normal Operation Shutdown DROPOUT VOLTAGE 1 ENABLE PIN Shutdown Voltage ENABLE Voltage ENABLE Pin Leakage Current OUTPUT VOLTAGE NOISE OUTPUT VOLTAGE NOISE DENSITY OUTPUT VOLTAGE HYSTERESIS 2 RIPPLE REJECTION RATIO LONG-TERM STABILITY TURN-ON SETTLING TIME
1 2
Symbol VOUT VOERR TCVOUT VO/VIN VO/IL
Conditions
Min 2.4975
Typ 2.500
-40C TA +125C VIN = 2.7 V to 5.5 V VIN = 2.7 V to 5.5 V, -40C TA +125C IL = 0 mA to 10 mA, VIN = 3.0 V, -40C TA +125C IL = 0 mA to -3 mA, VIN = 3.0 V, -40C TA +125C
2.5 5
Max 2.5025 0.1 2.5 8 50 120 30 50
Unit V % mV ppm/C ppm/V ppm/V ppm/mA ppm/mA
10 10
IL VIN = 3.0 V to 5.5 V VIN = 3.0 V to 5.5 V IQ ENABLE VIN x 0.85 ENABLE = VIN, -40C TA +125C ENABLE 0.7 V IL = 0 mA, TA = -40C TA +125C IL = 2 mA, TA = -40C TA +125C 0 VIN x 0.85 ENABLE = VIN, TA = -40C TA +125C f = 0.1 Hz to 10 Hz f = 10 Hz to 10 kHz f = 1 kHz TA = +25C to -40C to +125C to +25C fIN = 60 Hz 1000 hours at 50C CIN = 0.1 F, CL = 0.1 F, RLoad = 1 k 1 18 42 1 70 -60 30 600 85 100 5 200 250 0.7 VIN 3 A A A mV mV V V A V p-p V rms V/Hz ppm dB ppm s 10 -3 mA mA
VDO
50 75
VL VH IEN en p-p en VOUT_HYS RRR VOUT_LTD tR
Refers to the minimum difference between VIN and VOUT such that VOUT maintains a minimum accuracy of 0.1%. See the Terminology section. See the Terminology section. The part is placed through the temperature cycle in the order of temperatures shown.
Rev. B | Page 5 of 24
ADR3412/ADR3420/ADR3425/ADR3430/ADR3433/ADR3440/ADR3450
ADR3430 ELECTRICAL CHARACTERISTICS
VIN = 3.2 V to 5.5 V, IL = 0 mA, TA = 25C, unless otherwise noted. Table 6.
Parameter OUTPUT VOLTAGE INITIAL ACCURACY TEMPERATURE COEFFICIENT LINE REGULATION LOAD REGULATION Sourcing Sinking OUTPUT CURRENT CAPACITY Sourcing Sinking QUIESCENT CURRENT Normal Operation Shutdown DROPOUT VOLTAGE 1 ENABLE PIN Shutdown Voltage ENABLE Voltage ENABLE Pin Leakage Current OUTPUT VOLTAGE NOISE OUTPUT VOLTAGE NOISE DENSITY OUTPUT VOLTAGE HYSTERESIS 2 RIPPLE REJECTION RATIO LONG-TERM STABILITY TURN-ON SETTLING TIME
1 2
Symbol VOUT VOERR TCVOUT VO/VIN VO/IL
Conditions
Min 2.9970
Typ 3.0000
-40C TA +125C VIN = 3.2 V to 5.5 V VIN = 3.2 V to 5.5 V, -40C TA +125C IL = 0 mA to 10 mA, VIN = 3.5 V, -40C TA +125C IL = 0 mA to -3 mA, VIN = 3.5 V, -40C TA +125C
2.5 5
Max 3.0030 0.1 3.0 8 50 120 30 50
Unit V % mV ppm/C ppm/V ppm/V ppm/mA ppm/mA
9 10
IL VIN = 3.5 V to 5.5 V VIN = 3.5 V to 5.5 V IQ ENABLE VIN x 0.85 ENABLE = VIN, -40C TA +125C ENABLE 0.7 V IL = 0 mA, TA = -40C TA +125C IL = 2 mA, TA = -40C TA +125C 0 VIN x 0.85 ENABLE = VIN, TA = -40C TA +125C f = 0.1 Hz to 10 Hz f = 10 Hz to 10 kHz f = 1 kHz TA = +25C to -40C to +125C to +25C fIN = 60 Hz 1000 hours at 50C CIN = 0.1 F, CL = 0.1 F, RLoad = 1 k 0.85 22 45 1.1 70 -60 30 700 85 100 5 200 250 0.7 VIN 3 A A A mV mV V V A V p-p V rms V/Hz ppm dB ppm s 10 -3 mA mA
VDO
50 75
VL VH IEN en p-p en VOUT_HYS RRR VOUT_LTD tR
Refers to the minimum difference between VIN and VOUT such that VOUT maintains a minimum accuracy of 0.1%. See the Terminology section. See the Terminology section. The part is placed through the temperature cycle in the order of temperatures shown.
Rev. B | Page 6 of 24
ADR3412/ADR3420/ADR3425/ADR3430/ADR3433/ADR3440/ADR3450
ADR3433 ELECTRICAL CHARACTERISTICS
VIN = 3.5 V to 5.5 V, IL = 0 mA, TA = 25C, unless otherwise noted. Table 7.
Parameter OUTPUT VOLTAGE INITIAL ACCURACY TEMPERATURE COEFFICIENT LINE REGULATION LOAD REGULATION Sourcing Sinking OUTPUT CURRENT CAPACITY Sourcing Sinking QUIESCENT CURRENT Normal Operation Shutdown DROPOUT VOLTAGE 1 ENABLE PIN Shutdown Voltage ENABLE Voltage ENABLE Pin Leakage Current OUTPUT VOLTAGE NOISE OUTPUT VOLTAGE NOISE DENSITY OUTPUT VOLTAGE HYSTERESIS 2 RIPPLE REJECTION RATIO LONG-TERM STABILITY TURN-ON SETTLING TIME
1 2
Symbol VOUT VOERR TCVOUT VO/VIN VO/IL
Conditions
Min 3.2967
Typ 3.30
-40C TA +125C VIN = 3.5 V to 5.5 V VIN = 3.5 V to 5.5 V, -40C TA +125C IL = 0 mA to 10 mA, VIN = 3.8 V, -40C TA +125C IL = 0 mA to -3 mA, VIN = 3.8 V, -40C TA +125C
5
Max 3.3033 0.1 3.3 8 50 120 30 50
Unit V % mV ppm/C ppm/V ppm/V ppm/mA ppm/mA
9 10
IL VIN = 3.8 V to 5.5 V VIN = 3.8 V to 5.5 V IQ ENABLE > VIN x 0.85 ENABLE = VIN, -40C TA +125C ENABLE < 0.7 V IL = 0 mA, -40C TA +125C IL = 2 mA, -40C TA +125C 0 VIN x 0.85 ENABLE = VIN, -40C TA +125C f = 0.1 Hz to 10 Hz f = 10 Hz to 10 kHz f = 1 kHz TA = +25C to -40C to +125C to +25C fIN = 60 Hz 1000 hours at 50C CIN = 0.1 F, CL = 0.1 F, RLoad = 1 k 0.85 25 46 1.2 70 -60 30 750 85 100 5 200 250 0.7 VIN 3 A A A mV mV V V A V p-p V rms V/Hz ppm dB ppm s 10 -3 mA mA
VDO
50 75
VL VH IEN en p-p en VOUT_HYS RRR VOUT_LTD tR
Refers to the minimum difference between VIN and VOUT such that VOUT maintains a minimum accuracy of 0.1%. See the Terminology section. See the Terminology section. The part is placed through the temperature cycle in the order of temperatures shown.
Rev. B | Page 7 of 24
ADR3412/ADR3420/ADR3425/ADR3430/ADR3433/ADR3440/ADR3450
ADR3440 ELECTRICAL CHARACTERISTICS
VIN = 4.3 V to 5.5 V, IL = 0 mA, TA = 25C, unless otherwise noted. Table 8.
Parameter OUTPUT VOLTAGE INITIAL ACCURACY TEMPERATURE COEFFICIENT LINE REGULATION LOAD REGULATION Sourcing Sinking OUTPUT CURRENT CAPACITY Sourcing Sinking QUIESCENT CURRENT Normal Operation Shutdown DROPOUT VOLTAGE 1 ENABLE PIN Shutdown Voltage ENABLE Voltage ENABLE Pin Leakage Current OUTPUT VOLTAGE NOISE OUTPUT VOLTAGE NOISE DENSITY OUTPUT VOLTAGE HYSTERESIS 2 RIPPLE REJECTION RATIO LONG-TERM STABILITY TURN-ON SETTLING TIME
1 2
Symbol VOUT VOERR TCVOUT VO/VIN VO/IL
Conditions
Min 4.0919
Typ 4.0960
-40C TA +125C VIN = 4.3 V to 5.5 V VIN = 4.3 V to 5.5 V, -40C TA +125C IL = 0 mA to 10 mA, VIN = 4.6 V, -40C TA +125C IL = 0 mA to -3 mA, VIN = 4.6 V, -40C TA +125C
2.5 3
Max 4.1000 0.1 4.096 8 50 120 30 50
Unit V % mV ppm/C ppm/V ppm/V ppm/mA ppm/mA
6 15
IL VIN = 4.6 V to 5.5 V VIN = 4.6 V to 5.5 V IQ ENABLE VIN x 0.85 ENABLE = VIN, -40C TA +125C ENABLE 0.7 V IL = 0 mA, TA = -40C TA +125C IL = 2 mA, TA = -40C TA +125C 0 VIN x 0.85 ENABLE = VIN, TA = -40C TA +125C f = 0.1 Hz to 10 Hz f = 10 Hz to 10 kHz f = 1 kHz TA = +25C to -40C to +125C to +25C fIN = 60 Hz 1000 hours at 50C CIN = 0.1 F, CL = 0.1 F, RLoad = 1 k 29 53 1.4 70 -60 30 800 85 100 5 200 250 0.7 VIN 3 A A A mV mV V V A V p-p V rms V/Hz ppm dB ppm s 10 -3 mA mA
VDO
50 75
VL VH IEN en p-p en VOUT_HYS RRR VOUT_LTD tR
Refers to the minimum difference between VIN and VOUT such that VOUT maintains a minimum accuracy of 0.1%. See the Terminology section. See the Terminology section. The part is placed through the temperature cycle in the order of temperatures shown.
Rev. B | Page 8 of 24
ADR3412/ADR3420/ADR3425/ADR3430/ADR3433/ADR3440/ADR3450
ADR3450 ELECTRICAL CHARACTERISTICS
VIN = 5.2 V to 5.5 V, IL = 0 mA, TA = 25C, unless otherwise noted. Table 9.
Parameter OUTPUT VOLTAGE INITIAL ACCURACY TEMPERATURE COEFFICIENT LINE REGULATION LOAD REGULATION Sourcing Sinking OUTPUT CURRENT CAPACITY Sourcing Sinking QUIESCENT CURRENT Normal Operation Shutdown DROPOUT VOLTAGE 1 ENABLE PIN Shutdown Voltage ENABLE Voltage ENABLE Pin Leakage Current OUTPUT VOLTAGE NOISE OUTPUT VOLTAGE NOISE DENSITY OUTPUT VOLTAGE HYSTERESIS 2 RIPPLE REJECTION RATIO LONG-TERM STABILITY TURN-ON SETTLING TIME
1 2
Symbol VOUT VOERR TCVOUT VO/VIN VO/IL
Conditions
Min 4.9950
Typ 5.0000
-40C TA +125C VIN = 5.2 V to 5.5 V VIN = 5.2 V to 5.5 V, -40C TA +125C IL = 0 mA to 10 mA, VIN = 5.5 V, -40C TA +125C IL = 0 mA to -3 mA, VIN = 5.5 V, -40C TA +125C
2.5 3
Max 5.0050 0.1 5.0 8 50 120 30 50
Unit V % mV ppm/C ppm/V ppm/V ppm/mA ppm/mA
3 19
IL VIN = 5.5 V VIN = 5.5 V IQ ENABLE VIN x 0.85 ENABLE = VIN, -40C TA +125C ENABLE 0.7 V IL = 0 mA, TA = -40C TA +125C IL = 2 mA, TA = -40C TA +125C 0 VIN x 0.85 ENABLE = VIN, TA = -40C TA +125C f = 0.1 Hz to 10 Hz f = 10 Hz to 10 kHz f = 1 kHz TA = +25C to -40C to +125C to +25C fIN = 60 Hz 1000 hours at 50C CIN = 0.1 F, CL = 0.1 F, RLoad = 1 k 1 35 60 1.5 70 -58 30 900 85 100 5 200 250 0.7 VIN 3 A A A mV mV V V A V p-p V rms V/Hz ppm dB ppm s 10 -3 mA mA
VDO
50 75
VL VH IEN en p-p en VOUT_HYS RRR VOUT_LTD tR
Refers to the minimum difference between VIN and VOUT such that VOUT maintains a minimum accuracy of 0.1%. See the Terminology section. See the Terminology section. The part is placed through the temperature cycle in the order of temperatures shown.
Rev. B | Page 9 of 24
ADR3412/ADR3420/ADR3425/ADR3430/ADR3433/ADR3440/ADR3450
ABSOLUTE MAXIMUM RATINGS AND MINIMUM OPERATING CONDITION
TA = 25C, unless otherwise noted. Table 10.
Parameter Supply Voltage ENABLE to GND SENSE Voltage VIN Minimum Slew Rate Operating Temperature Range Storage Temperature Range Junction Temperature Range Rating 6V VIN 0.1 V/ms -40C to +125C -65C to +125C -65C to +150C
THERMAL RESISTANCE
JA is specified for the worst-case conditions, that is, a device soldered in a circuit board for surface-mount packages. Table 11. Thermal Resistance
Package Type 6-Lead SOT-23 (RJ-6) JA 230 JC 92 Unit C/W
ESD CAUTION
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. B | Page 10 of 24
ADR3412/ADR3420/ADR3425/ADR3430/ADR3433/ADR3440/ADR3450 PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
GND FORCE 1
6
ADR34xx
GND SENSE 2
5
VOUT FORCE VOUT SENSE
08440-002
TOP VIEW ENABLE 3 (Not to Scale) 4 VIN
Figure 2. Pin Configuration
Table 12. Pin Function Descriptions
Pin No. 1 2 3 4 5 6
1
Mnemonic GND FORCE GND SENSE ENABLE VIN VOUT SENSE VOUT FORCE
Description Ground Force Connection. 1 Ground Voltage Sense Connection. Connect directly to the point of lowest potential in the application.1 Enable Connection. Enables or disables the device. Input Voltage Connection. Reference Voltage Output Sensing Connection. Connect directly to the voltage input of the load devices.1 Reference Voltage Output.1
See the Applications Information section for more information on force/sense connections.
Rev. B | Page 11 of 24
ADR3412/ADR3420/ADR3425/ADR3430/ADR3433/ADR3440/ADR3450 TYPICAL PERFORMANCE CHARACTERISTICS
TA = 25C, unless otherwise noted.
2.5010 2.5008 2.5006
OUTPUT VOLTAGE (V)
OUTPUT VOLTAGE (V)
5.0025
VIN = 5.5V
5.0020 5.0015 5.0010 5.0005 5.0000 4.9995 4.9990 4.9985 4.9980
VIN = 5.5V
2.5004 2.5002 2.5000 2.4998 2.4996 2.4994 2.4992
-25 -10 5 20 35 50 65 80 95 110 125
08440-003
-25
-10
5
20
35
50
65
80
95
110
125
TEMPERATURE (C)
TEMPERATURE (C)
Figure 3. ADR3425 Output Voltage vs. Temperature
40 35 30 NUMBER OF DEVICES NUMBER OF DEVICES 25 20 15 10 5
08440-005
Figure 6. ADR3450 Output Voltage vs. Temperature
45 40 35 30 25 20 15 10 5 0
0
0
1
2
3
4
5
6
7
8
9
10 MORE
TEMPERATURE COEFFICIENT (ppm/C)
Figure 4. ADR3425 Temperature Coefficient Distribution
24 22 20
LOAD REGULATION (ppm/mA)
Figure 7. ADR3450 Temperature Coefficient Distribution
35
18 16 14 12 10 8 6 4
LOAD REGULATION (ppm/mA)
ADR3412 ADR3420 ADR3425 ADR3430 ADR3433 ADR3440 ADR3450
IL = 0mA TO +10mA SOURCING
30
25
ADR3412 ADR3420 ADR3425 ADR3430 ADR3433 ADR3440 ADR3450
IL = 0mA TO -3mA SINKING
20
15
10
08440-054
2 0 -40 -25 -10 5 20 50 65 35 TEMPERATURE (C) 80 95 110
08440-053
125
5 -40
-25
-10
5
20 35 50 65 TEMPERATURE (C)
80
95
110
125
Figure 5. Load Regulation vs. Temperature (Sourcing)
Figure 8. Load Regulation vs. Temperature (Sinking)
Rev. B | Page 12 of 24
08440-006
0
1
2 3 4 5 6 7 8 9 TEMPERATURE COEFFICIENT (ppm/C)
10
11
08440-004
2.4990 -40
4.9975 -40
ADR3412/ADR3420/ADR3425/ADR3430/ADR3433/ADR3440/ADR3450
1.20 1.15 1.10 1.05 1.00 0.95 0.90
08440-056
400 350 -40C +25C +125C
DIFFERENTIAL VOLTAGE (mV)
2 3 4 5 6 7 8 9 10
DIFFERENTIAL VOLTAGE (V)
300 250 200 150 100 50 0 -3
TA = -40C TA = +25C TA = +125C
0.85 0.80 -3
-2
-1
0
1
2
3
4
5
6
7
8
9
10
LOAD CURRENT (mA)
LOAD CURRENT (mA)
Figure 9. ADR3412 Dropout Voltage vs. Load Current
450 400
Figure 12. ADR3425 Dropout Voltage vs. Load Current
350 300 -40C +25C +125C
DIFFERENTIAL VOLTAGE (mV)
DIFFERENTIAL VOLTAGE (mV)
350 300 250 200 150 100 50 0 -50 -3 -2 -1 0 1 2 3 4 5 6 7 8 9
08440-057
TA = -40C TA = +25C TA = +125C
250 200 150 100 50 0 -3
-2
-1
0
1
2
3
4
5
6
7
8
9
10
LOAD CURRENT (mA)
LOAD CURRENT (mA)
Figure 10. ADR3420 Dropout Voltage vs. Load Current
140
FREQUENCY GEN = 1Hz
LINE REGULATION (ppm/V)
Figure 13. ADR3450 Dropout Voltage vs. Load Current
ADR3412 ADR3420 ADR3425 ADR3430 ADR3433 ADR3440 ADR3450
120 100 80 60 40 20
VIN = 2V/DIV CIN = COUT = 0.1F RL = 1k
2
VOUT = 500mV/DIV
08440-055
1
CH1 500mV
CH2 2.00V
M100s
A CH2
2.36V
-10
5
20
35
50
65
80
95
110
125
TEMPERATURE (C)
Figure 11. ADR3412 Start-Up (Turn-On Settle) Time
Figure 14. Line Regulation vs. Temperature
Rev. B | Page 13 of 24
08440-052
0 -40 -25
08440-016
10
08440-015
-2
-1
0
1
ADR3412/ADR3420/ADR3425/ADR3430/ADR3433/ADR3440/ADR3450
0
RIPPLE REJECTION RATIO (dB VOUT/VIN)
-10 -20 -30 -40 -50 -60 -70 -80 -90 10
CL = 1.1F CIN = 0.1F
1
10V/DIV
TIME = 1s/DIV CH1 pk-pk = 18V CH1 RMS = 3.14V
08440-028
100
1k FREQUENCY (Hz)
10k
100k
Figure 15. ADR3425 Output Voltage Noise (0.1 Hz to 10 Hz)
Figure 18. ADR3425 Ripple Rejection Ratio vs. Frequency
CIN = CL = 0.1F RL =
1
VIN = 2V/DIV
1
100V/DIV
TIME = 200s/DIV
08440-029
TIME = 1s/DIV CH1 pk-pk = 300V CH1 RMS = 42.0V
VOUT = 1V/DIV
Figure 16. ADR3425 Output Voltage Noise (10 Hz to 10 kHz)
12
Figure 19. ADR3425 Start-Up Response
10 NOISE DENSITY (Vp-p /Hz)
ENABLE
8
VENABLE = 1V/DIV VIN = 3.0v CIN = CL = 0.1F RL =
6
1
4
VOUT = 1V/DIV TIME = 200s/DIV
08440-031
2
2
1
10
100
1k
10k
FREQUENCY (Hz)
Figure 17. ADR3425 Output Noise Spectral Density
08440-023
0 0.1
Figure 20. ADR3425 Restart Response from Shutdown
Rev. B | Page 14 of 24
08440-030
2
08440-025
ADR3412/ADR3420/ADR3425/ADR3430/ADR3433/ADR3440/ADR3450
0
RIPPLE REJECTION RATIO (dB VOUT/VIN)
-10 -20 -30 -40 -50 -60 -70 -80 -90 10
CL = 1.1F CIN = 0.1F
1
10V/DIV
100
1k FREQUENCY (Hz)
10k
100k
Figure 21. ADR3450 Output Voltage Noise (0.1 Hz to 10 Hz)
Figure 24. ADR3450 Ripple Rejection Ratio vs. Frequency
VIN 2V/DIV
1
1
CIN = 0F CL = 0.1F RL =
100V/DIV
08440-033
VOUT 2V/DIV
2
TIME = 200s/DIV
08440-034
CH1 pk-pk = 446V
CH1 RMS = 60.3V
Figure 22. ADR3450 Output Voltage Noise (10 Hz to 10 kHz)
12
Figure 25. ADR3450 Start-Up Response
10 NOISE DENSITY (Vp-p/Hz)
ENABLE VENABLE = 2V/DIV VIN = 5.5V CIN = CL = 0.1F RL =
8
1
6
VOUT = 2V/DIV
4
2
TIME = 200s/DIV
08440-035
2
1
10
100
1k
10k
FREQUENCY (Hz)
Figure 23. ADR3450 Output Noise Spectral Density
08440-024
0 0.1
Figure 26. ADR3450 Restart Response from Shutdown
Rev. B | Page 15 of 24
08440-026
CH1 pk-pk = 33.4V
CH1 RMS = 5.68V
08440-032
ADR3412/ADR3420/ADR3425/ADR3430/ADR3433/ADR3440/ADR3450
ENABLE 1V/DIV CIN = CL = 0.1F VIN = 3V RL = 1k
1
ENABLE 2V/DIV
CIN = CL = 0.1F VIN = 5V RL = 1k
1
TIME = 200s/DIV
TIME = 200s/DIV
Figure 27. ADR3425 Shutdown Response
Figure 30. ADR3450 Shutdown Response
VIN = 100mV/DIV
3.2V 2.7V 500mV/DIV CIN = CL = 0.1F
1
5.5V
CIN = CL = 0.1F
5.2V
2
VOUT = 10mV/DIV
2
VOUT = 5mV/DIV
08440-037
08440-039
08440-036
2
VOUT = 1V/DIV
2
VOUT = 2V/DIV
TIME = 1ms/DIV
1
TIME = 1ms/DIV
Figure 28. ADR3425 Line Transient Response
IL
Figure 31. ADR3450 Line Transient Response
+10mA SINKING -3mA
SOURCING IL SINKING SINKING -3mA CIN = 0.1F CL = 0.1F RL = 250 +10mA
SOURCING
SINKING
CIN = 0.1F CL = 0.1F RL = 500 5.0V
2.5V VOUT = 20mV/DIV
08440-038
VOUT = 20mV/DIV
TIME = 1ms/DIV
TIME = 1ms/DIV
Figure 29. ADR3425 Load Transient Response
Figure 32. ADR3450 Load Transient Response
Rev. B | Page 16 of 24
08440-041
08440-040
ADR3412/ADR3420/ADR3425/ADR3430/ADR3433/ADR3440/ADR3450
100 90 80 VIN = 5.5 V
7 6 5 4 3 2 1 0
-0.050 -0.045 -0.040 -0.035 -0.030 -0.025 -0.020 -0.015 -0.010 -0.005 0 0.005 0.010 0.015 0.020 0.025 0.030 0.035 0.040 0.045 0.050 0.055
08440-043 08440-045
SUPPLY CURRENT (A)
70 60 50 40 30 20 10 0 -40 -25 -10 5 20 35 50 65 80 95 110
08440-042
125
TEMPERATURE (C)
NUMBER OF DEVICES
RELATIVE SHIFT IN VOUT (%)
Figure 33. Supply Current vs. Temperature
2.0 1.8 1.6
-40C +25C +125C
Figure 36. Output Voltage Drift Distribution After Reflow (SHR Drift)
8 TA = +25C +150C -50C +25C 7 6
NUMBER OF DEVICES
SUPPLY CURRENT (mA)
1.4 1.2 1.0 0.8 0.6 0.4 0.2 0
5 4 3 2
08440-044
1 0
-110 -10 0 10 20 30 -90 -80 -70 -60 -50 -40 -30 -150 -140 -130 -120 -100 -20 40
0
10
20
30
40
50
60
70
80
90
100
ENABLE VOLTAGE (% of VIN)
08440-008
OUTPUT VOLTAGE HYSTERESIS (ppm)
Figure 34. Supply Current vs. ENABLE Pin Voltage
10 CL = 0.1F CL = 1.1F
Figure 37. ADR3450 Thermally Induced Output Voltage Hysteresis Distribution
80
LONG-TERM OUTPUT VOLTAGE DRIFT (ppm)
60 40 20 0 -20 -40 -60 -80
OUTPUT IMPEDANCE ()
1
0.1
0.1
1
10
100
1k
10k
08440-027
0.01 0.01
0
200
400
600
800
1000
FREQUENCY (Hz)
ELAPSED TIME (Hours)
Figure 35. ADR3450 Output Impedance vs. Frequency
Figure 38. ADR3450 Typical Long-Term Output Voltage Drift (Four Devices, 1000 Hours)
Rev. B | Page 17 of 24
ADR3412/ADR3420/ADR3425/ADR3430/ADR3433/ADR3440/ADR3450 TERMINOLOGY
Dropout Voltage (VDO) Dropout voltage, sometimes referred to as supply voltage headroom or supply-output voltage differential, is defined as the minimum voltage differential between the input and output such that the output voltage is maintained to within 0.1% accuracy. VDO = (VIN - VOUT)min | IL = constant Because the dropout voltage depends upon the current passing through the device, it is always specified for a given load current. In series-mode devices, dropout voltage typically increases proportionally to load current (see Figure 8 and Figure 14). Temperature Coefficient (TCVOUT) The temperature coefficient relates the change in output voltage to the change in ambient temperature of the device, as normalized by the output voltage at 25C. This parameter is expressed in ppm/C and can be determined by the following equation:
VOUT _ HYS = VOUT (25C ) - VOUT _ TC [V] VOUT _ HYS = VOUT (25C ) - VOUT _ TC VOUT (25C ) x 10 6 [ppm]
where: VOUT(25C) is the output voltage at 25C. VOUT_TC is the output voltage after temperature cycling.
Long-Term Stability (VOUT_LTD) Long-term stability refers to the shift in output voltage at 50C after 1000 hours of operation in a 50C environment. Ambient temperature is kept at 50C to ensure that the temperature chamber does not switch randomly between heating and cooling, which can cause instability over the 1000 hour measurement. This is also expressed as either a shift in voltage or a difference in ppm from the nominal output.
VOUT _ LTD = VOUT (t 1 ) - VOUT (t 0 ) [V]
VOUT _ LTD =
VOUT (t 1 ) - VOUT (t 0 ) VOUT (t 0 )
TCVOUT =
max{VOUT (T1 , T2 , T3 )} - min{VOUT (T1 , T2 , T3 )} VOUT (T2 ) x (T3 - T1 )
x
x 10 6 [ppm]
10 6 [ ppm / C] (1) where: VOUT(T) is the output voltage at Temperature T. T1 = -40C. T2 = +25C. T3 = +125C. This three-point method ensures that TCVOUT accurately portrays the maximum difference between any of the three temperatures at which the output voltage of the part is measured. The TCVOUT for the ADR3412/ADR3425/ADR3430/ADR3433/ ADR3440/ADR3450 is guaranteed via statistical means. This is accomplished by recording output voltage data for a large number of units over temperature, computing TCVOUT for each individual device via Equation 1, then defining the maximum TCVOUT limits as the mean TCVOUT for all devices extended by six standard deviations (6).
Thermally Induced Output Voltage Hysteresis (VOUT_HYS) Thermally induced output voltage hysteresis represents the change in output voltage after the device is exposed to a specified temperature cycle. This is expressed as either a shift in voltage or a difference in ppm from the nominal output.
where: VOUT(t0) is the VOUT at 50C at Time 0. VOUT(t1) is the VOUT at 50C after 1000 hours of operation at 50C.
Line Regulation Line regulation refers to the change in output voltage in response to a given change in input voltage and is expressed in percent per volt, ppm per volt, or V per volt change in input voltage. This parameter accounts for the effects of self-heating. Load Regulation Load regulation refers to the change in output voltage in response to a given change in load current and is expressed in V per mA, ppm per mA, or ohms of dc output resistance. This parameter accounts for the effects of self-heating. Solder Heat Resistance (SHR) Drift SHR drift refers to the permanent shift in output voltage induced by exposure to reflow soldering, expressed in units of ppm. This is caused by changes in the stress exhibited upon the die by the package materials when exposed to high temperatures. This effect is more pronounced in lead-free soldering processes due to higher reflow temperatures.
Rev. B | Page 18 of 24
ADR3412/ADR3420/ADR3425/ADR3430/ADR3433/ADR3440/ADR3450 THEORY OF OPERATION
VIN
LONG-TERM STABILITY
One of the key parameters of the ADR34xx references is longterm stability. Regardless of output voltage, internal testing during development showed a typical drift of approximately 30 ppm after 1000 hours of continuous, nonloaded operation in a 50C environment. It is important to understand that long-term stability is not guaranteed by design and that the output from the device may shift beyond the typical 30 ppm specification at any time, especially during the first 200 hours of operation. For systems that require highly stable output voltages over long periods of time, the designer should consider burning in the devices prior to use to minimize the amount of output drift exhibited by the reference over time. See the AN-713 Application Note, The Effect of Long-Term Drift on Voltage References, at www.analog.com for more information regarding the effects of long-term drift and how it can be minimized.
ENABLE
BAND GAP VOLTAGE REFERENCE
VBG VOUT FORCE VOUT SENSE RFB1 GND FORCE RFB2
08440-046
GND SENSE
Figure 39. Block Diagram
The ADR3412/ADR3425/ADR3430/ADR3433/ADR3440/ ADR3450 use a patented voltage reference architecture to achieve high accuracy, low temperature coefficient (TC), and low noise in a CMOS process. Like all band gap references, the references combine two voltages of opposite TCs to create an output voltage that is nearly independent of ambient temperature. However, unlike traditional band gap voltage references, the temperature-independent voltage of the references are arranged to be the base-emitter voltage, VBE, of a bipolar transistor at room temperature rather than the VBE extrapolated to 0 K (the VBE of bipolar transistor at 0 K is approximately VG0, the band gap voltage of silicon). A corresponding positive-TC voltage is then added to the VBE voltage to compensate for its negative TC. The key benefit of this technique is that the trimming of the initial accuracy and TC can be performed without interfering with one another, thereby increasing overall accuracy across temperature. Curvature correction techniques further reduce the temperature variation. The band gap voltage (VBG) is then buffered and amplified to produce stable output voltages of 2.5 V and 5.0 V. The output buffer can source up to 10 mA and sink up to -3 mA of load current. The ADR34xx family leverages Analog Devices patented DigiTrim technology to achieve high initial accuracy and low TC, and precision layout techniques lead to very low long-term drift and thermal hysteresis.
POWER DISSIPATION
The ADR34xx voltage references are capable of sourcing up to 10 mA of load current at room temperature across the rated input voltage range. However, when used in applications subject to high ambient temperatures, the input voltage and load current should be carefully monitored to ensure that the device does not exceeded its maximum power dissipation rating. The maximum power dissipation of the device can be calculated via the following equation:
PD = TJ - TA JA [W ]
where: PD is the device power dissipation. TJ is the device junction temperature. TA is the ambient temperature. JA is the package (junction-to-air) thermal resistance. Because of this relationship, acceptable load current in high temperature conditions may be less than the maximum currentsourcing capability of the device. In no case should the part be operated outside of its maximum power rating because doing so can result in premature failure or permanent damage to the device.
Rev. B | Page 19 of 24
ADR3412/ADR3420/ADR3425/ADR3430/ADR3433/ADR3440/ADR3450 APPLICATIONS INFORMATION
BASIC VOLTAGE REFERENCE CONNECTION
VIN 2.7V TO 5.5V
4 3
VIN ENABLE
VOUT FORCE 6 VOUT SENSE 5
VOUT 2.5V
1F
0.1F
ADR34xx
GND SENSE 2 GND FORCE 1
0.1F
08440-047
voltages can be sensed accurately. These voltages are fed back into the internal amplifier and used to automatically correct for the voltage drop across the current-carrying output and ground lines, resulting in a highly accurate output voltage across the load. To achieve the best performance, the sense connections should be connected directly to the point in the load where the output voltage should be the most accurate. See Figure 41 for an example application.
OUTPUT CAPACITOR(S) SHOULD BE MOUNTED AS CLOSE TO VOUT FORCE PIN AS POSSIBLE. 0.1F VIN
4V IN 3 ENABLE
Figure 40. Basic Reference Connection
The circuit shown in Figure 40 illustrates the basic configuration for the ADR34xx references. Bypass capacitors should be connected according to the following guidelines.
VOUT FORCE 6 VOUT SENSE 5 LOAD SENSE CONNECTIONS SHOULD CONNECT AS CLOSE TO LOAD DEVICE AS POSSIBLE.
INPUT AND OUTPUT CAPACITORS
A 1 F to 10 F electrolytic or ceramic capacitor can be connected to the input to improve transient response in applications where the supply voltage may fluctuate. An additional 0.1 F ceramic capacitor should be connected in parallel to reduce high frequency supply noise. A ceramic capacitor of at least a 0.1 F must be connected to the output to improve stability and help filter out high frequency noise. An additional 1 F to 10 F electrolytic or ceramic capacitor can be added in parallel to improve transient performance in response to sudden changes in load current; however, the designer should keep in mind that doing so increases the turn-on time of the device. Best performance and stability is attained with low ESR (for example, less than 1 ), low inductance ceramic chip-type output capacitors (X5R, X7R, or similar). If using an electrolytic capacitor on the output, a 0.1 F ceramic capacitor should be placed in parallel to reduce overall ESR on the output.
1F 0.1F
ADR34xx
GND SENSE 2 GND FORCE 1
Figure 41. Application Showing Kelvin Connection
It is always advantageous to use Kelvin connections whenever possible. However, in applications where the IR drop is negligible or an extra set of traces cannot be routed to the load, the force and sense pins for both VOUT and GND can simply be tied together, and the device can be used in the same fashion as a normal 3-terminal reference (as shown in Figure 40).
VIN SLEW RATE CONSIDERATIONS
In applications with slow-rising input voltage signals, the reference exhibits overshoot or other transient anomalies that appear on the output. These phenomena also appear during shutdown as the internal circuitry loses power. To avoid such conditions, ensure that the input voltage waveform has both a rising and falling slew rate of at least 0.1 V/ms.
4-WIRE KELVIN CONNECTIONS
Current flowing through a PCB trace produces an IR voltage drop, and with longer traces, this drop can reach several millivolts or more, introducing a considerable error into the output voltage of the reference. A 1 inch long, 5 millimeter wide trace of 1 ounce copper has a resistance of approximately 100 m at room temperature; at a load current of 10 mA, this can introduce a full millivolt of error. In an ideal board layout, the reference should be mounted as close to the load as possible to minimize the length of the output traces, and, therefore, the error introduced by voltage drop. However, in applications where this is not possible or convenient, force and sense connections (sometimes referred to as Kelvin sensing connections) are provided as a means of minimizing the IR drop and improving accuracy. Kelvin connections work by providing a set of high impedance voltage-sensing lines to the output and ground nodes. Because very little current flows through these connections, the IR drop across their traces is negligible, and the output and ground
SHUTDOWN/ENABLE FEATURE
The ADR34xx references can be switched to a low power shutdown mode when a voltage of 0.7 V or lower is input to the ENABLE pin. Likewise, the reference becomes operational for ENABLE voltages of 0.85 x VIN or higher. During shutdown, the supply current drops to less than 5 A, useful in applications that are sensitive to power consumption. If using the shutdown feature, ensure that the ENABLE pin voltage does not fall between 0.7 V and 0.85 x VIN because this causes a large increase in the supply current of the device and may keep the reference from starting up correctly (see Figure 34). If not using the shutdown feature, however, the ENABLE pin can simply be tied to the VIN pin, and the reference remains operational continuously.
Rev. B | Page 20 of 24
08440-048
ADR3412/ADR3420/ADR3425/ADR3430/ADR3433/ADR3440/ADR3450
SAMPLE APPLICATIONS
Negative Reference
Figure 42 shows how to connect the ADR3450 and a standard CMOS op amp, such as the AD8663, to provide a negative reference voltage. This configuration provides two main advantages: first, it only requires two devices and, therefore, does not require excessive board space; second, and more importantly, it does not require any external resistors, meaning that the performance of this circuit does not rely on choosing expensive parts with low temperature coefficients to ensure accuracy.
+VDD 1F 0.1F
VIN
4V IN
VOUT FORCE 6 R1 10k 0.1F R2 10k
+5V
3 ENABLE V 5 OUT SENSE
1F
0.1F
ADR3450
GND SENSE 2 GND FORCE 1
+15V
ADA4000-1
R3 5k
-5V
-15V
Figure 43. ADR3450 Bipolar Output Reference
4 3
VIN
VOUT FORCE
6
AD8663
-5V 0.1F -VDD 0.1F
08440-049
Boosted Output Current Reference
Figure 44 shows a configuration for obtaining higher current drive capability from the ADR34xx references without sacrificing accuracy. The op amp regulates the current flow through the MOSFET until VOUT equals the output voltage of the reference; current is then drawn directly from VIN instead of from the reference itself, allowing increased current drive capability.
VIN
ENABLE VOUT SENSE 5
ADR3450
GND SENSE 2 GND FORCE 1
Figure 42. ADR3450 Negative Reference
In this configuration, the VOUT pins of the reference sit at virtual ground, and the negative reference voltage and load current are taken directly from the output of the operational amplifier. Note that in applications where the negative supply voltage is close to the reference output voltage, a dual-supply, low offset, rail-torail output amplifier must be used to ensure an accurate output voltage. The operational amplifier must also be able to source or sink an appropriate amount of current for the application.
U6
4 3
+16V R1 100 2N7002
VIN ENABLE
VOUT FORCE 6 VOUT SENSE 5 0.1F
AD8663
VOUT CL 0.1F
1F 0.1F
ADR34xx
Bipolar Output Reference
Figure 43 shows a bipolar reference configuration. By connecting the output of the ADR3450 to the inverting terminal of an operational amplifier, it is possible to obtain both positive and negative reference voltages. R1 and R2 must be matched as closely as possible to ensure minimal difference between the negative and positive outputs. Resistors with low temperature coefficients must also be used if the circuit is used in environments with large temperature swings; otherwise, a voltage difference develops between the two outputs as the ambient temperature changes.
GND SENSE 2 GND FORCE 1
RL 200
Figure 44. Boosted Output Current Reference
Because the current-sourcing capability of this circuit depends only on the ID rating of the MOSFET, the output drive capability can be adjusted to the application simply by choosing an appropriate MOSFET. In all cases, the VOUT SENSE pin should be tied directly to the load device to maintain maximum output voltage accuracy.
Rev. B | Page 21 of 24
08440-051
08440-050
ADR3412/ADR3420/ADR3425/ADR3430/ADR3433/ADR3440/ADR3450 OUTLINE DIMENSIONS
3.00 2.90 2.80
1.70 1.60 1.50 PIN 1 INDICATOR
6
5
4
3.00 2.80 2.60
1
2
3
0.95 BSC 1.90 BSC
1.30 1.15 0.90
1.45 MAX 0.95 MIN
0.20 MAX 0.08 MIN 10 4 0 0.55 0.45 0.35
121608-A
0.15 MAX 0.05 MIN
0.50 MAX 0.30 MIN
SEATING PLANE
0.60 BSC
COMPLIANT TO JEDEC STANDARDS MO-178-AB
Figure 45. 6-Lead Small Outline Transistor Package (SOT-23) (RJ-6) Dimensions shown in millimeters
ORDERING GUIDE
Model 1 ADR3412ARJZ-R2 ADR3412ARJZ-R7 ADR3420ARJZ-R2 ADR3420ARJZ-R7 ADR3425ARJZ-R2 ADR3425ARJZ-R7 ADR3430ARJZ-R2 ADR3430ARJZ-R7 ADR3433ARJZ-R2 ADR3433ARJZ-R7 ADR3440ARJZ-R2 ADR3440ARJZ-R7 ADR3450ARJZ-R2 ADR3450ARJZ-R7
1
Output Voltage (V) 1.200 1.200 2.048 2.048 2.500 2.500 3.000 3.000 3.300 3.300 4.096 4.096 5.000 5.000
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
Package Description 6-Lead SOT-23 6-Lead SOT-23 6-Lead SOT-23 6-Lead SOT-23 6-Lead SOT-23 6-Lead SOT-23 6-Lead SOT-23 6-Lead SOT-23 6-Lead SOT-23 6-Lead SOT-23 6-Lead SOT-23 6-Lead SOT-23 6-Lead SOT-23 6-Lead SOT-23
Package Option RJ-6 RJ-6 RJ-6 RJ-6 RJ-6 RJ-6 RJ-6 RJ-6 RJ-6 RJ-6 RJ-6 RJ-6 RJ-6 RJ-6
Ordering Quantity 250 3,000 250 3,000 250 3,000 250 3,000 250 3,000 250 3,000 250 3,000
Branding R2R R2R R2V R2V R2X R2X R2Z R2Z R31 R31 R33 R33 R34 R34
Z = RoHS Compliant Part.
Rev. B | Page 22 of 24
ADR3412/ADR3420/ADR3425/ADR3430/ADR3433/ADR3440/ADR3450 NOTES
Rev. B | Page 23 of 24
ADR3412/ADR3420/ADR3425/ADR3430/ADR3433/ADR3440/ADR3450 NOTES
(c)2010 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D08440-0-6/10(B)
Rev. B | Page 24 of 24

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