Ultralow Noise, LDO XFET® Voltage References with Current Sink and Source ADR440/ADR441/ADR443/ADR444/ADR445 PIN CONFIGURATIONS Ultralow noise (0.1 Hz to 10 Hz) ADR440: 1 μV p-p ADR441: 1.2 μV p-p ADR443: 1.4 μV p-p ADR444: 1.8 μV p-p ADR445: 2.25 μV p-p Superb temperature coefficient A Grade: 10 ppm/°C B Grade: 3 ppm/°C Low dropout operation: 500 mV Input range: (VOUT + 500 mV) to 18 V High output source and sink current: +10 mA and −5 mA Wide temperature range: −40°C to +125°C TP 1 VIN 2 NC 3 GND 4 ADR440/ ADR441/ ADR443/ ADR444/ ADR445 TOP VIEW (Not to Scale) 8 TP 7 NC 6 VOUT 5 TRIM NOTES 1. NC = NO CONNECT 2. TP = TEST PIN (DO NOT CONNECT) 05428-001 FEATURES TP 1 VIN 2 NC 3 APPLICATIONS GND 4 Precision data acquisition systems High resolution data converters Battery-powered instrumentations Portable medical instruments Industrial process control systems Precision instruments Optical control circuits ADR440/ ADR441/ ADR443/ ADR444/ ADR445 TOP VIEW (Not to Scale) 8 TP 7 NC 6 VOUT 5 TRIM NOTES 1. NC = NO CONNECT 2. TP = TEST PIN (DO NOT CONNECT) 05428-002 Figure 1. 8-Lead SOIC_N (R-Suffix) Figure 2. 8-Lead MSOP (RM-Suffix) GENERAL DESCRIPTION The ADR44x series is a family of XFET voltage references featuring ultralow noise, high accuracy, and low temperature drift performance. Using Analog Devices, Inc., patented temperature drift curvature correction and XFET (eXtra implanted junction FET) technology, voltage change vs. temperature nonlinearity in the ADR44x is greatly minimized. The XFET references offer better noise performance than buried Zener references, and XFET references operate off low supply voltage headroom (0.5 V). This combination of features makes the ADR44x family ideally suited for precision signal conversion applications in high-end data acquisition systems, optical networks, and medical applications. The ADR44x family has the capability to source up to 10 mA of output current and sink up to 5 mA. It also comes with a trim terminal to adjust the output voltage over a 0.5% range without compromising performance. Offered in two electrical grades, the ADR44x family is available in 8-lead MSOP and narrow SOIC packages. All versions are specified over the extended industrial temperature range of −40°C to +125°C. Table 1. Selection Guide Model ADR440A ADR440B ADR441A ADR441B ADR443A ADR443B ADR444A ADR444B ADR445A ADR445B Output Voltage (V) 2.048 2.048 2.500 2.500 3.000 3.000 4.096 4.096 5.000 5.000 Initial Accuracy, ± (mV) 3 1 3 1 4 1.2 5 1.6 6 2 Temperature Coefficient (ppm/°C) 10 3 10 3 10 3 10 3 10 3 Rev. A Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties 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: 781.461.3113 ©2006 Analog Devices, Inc. All rights reserved. ADR440/ADR441/ADR443/ADR444/ADR445 TABLE OF CONTENTS Features .............................................................................................. 1 Theory of Operation ...................................................................... 14 Applications....................................................................................... 1 Power Dissipation Considerations........................................... 14 Pin Configurations ........................................................................... 1 Basic Voltage Reference Connections ..................................... 14 General Description ......................................................................... 1 Noise Performance ..................................................................... 14 Revision History ............................................................................... 2 Turn-On Time ............................................................................ 14 Specifications..................................................................................... 3 Applications..................................................................................... 15 ADR440 Electrical Characteristics............................................. 3 Output Adjustment .................................................................... 15 ADR441 Electrical Characteristics............................................. 4 Bipolar Outputs .......................................................................... 15 ADR443 Electrical Characteristics............................................. 5 Negative Reference..................................................................... 15 ADR444 Electrical Characteristics............................................. 6 Programmable Voltage Source ................................................. 16 ADR445 Electrical Characteristics............................................. 7 Programmable Current Source ................................................ 16 Absolute Maximum Ratings............................................................ 8 High Voltage Floating Current Source .................................... 16 Thermal Resistance ...................................................................... 8 Precision Output Regulator (Boosted Reference).................. 17 ESD Caution.................................................................................. 8 Outline Dimensions ....................................................................... 18 Typical Performance Characteristics ............................................. 9 Ordering Guide .......................................................................... 19 REVISION HISTORY 9/06—Rev. 0 to Rev. A Updated Format..................................................................Universal Changes to Features.......................................................................... 1 Changes to Pin Configurations....................................................... 1 Changes to the Specifications Section ........................................... 3 Changes to Figure 4 and Figure 5................................................... 9 Inserted Figure 6 and Figure 7 ........................................................ 9 Changes to Figure 15...................................................................... 11 Changes to the Power Dissipation Considerations Section...... 14 Changes to Figure 35 and Figure 36............................................. 15 Changes to Figure 38 and Table 9................................................. 16 Updated Outline Dimensions ....................................................... 18 Changes to Ordering Guide .......................................................... 19 10/05—Revision 0: Initial Version Rev. A | Page 2 of 20 ADR440/ADR441/ADR443/ADR444/ADR445 SPECIFICATIONS ADR440 ELECTRICAL CHARACTERISTICS VIN = 3 V to 18 V, TA = 25°C, CIN = COUT = 0.1 μF, unless otherwise noted. Table 2. Parameter OUTPUT VOLTAGE A Grade B Grade INITIAL ACCURACY A Grade Symbol VO Conditions Min Typ Max Unit 2.045 2.047 2.048 2.048 2.051 2.049 V V 3 0.15 1 0.05 mV % mV % 10 3 +20 ppm/°C ppm/°C ppm/V +50 ppm/mA +50 3.75 ppm/mA mA μV p-p nV/√Hz μs ppm ppm dB mA V mV VOERR B Grade TEMPERATURE DRIFT A Grade B Grade LINE REGULATION LOAD REGULATION TCVO ΔVO/ΔVIN ΔVO/ΔILOAD ΔVO/ΔILOAD QUIESCENT CURRENT VOLTAGE NOISE VOLTAGE NOISE DENSITY TURN-ON SETTLING TIME LONG-TERM STABILITY 1 OUTPUT VOLTAGE HYSTERESIS RIPPLE REJECTION RATIO SHORT CIRCUIT TO GND SUPPLY VOLTAGE OPERATING RANGE SUPPLY VOLTAGE HEADROOM 1 IIN eN p-p eN tR VO VO_HYS RRR ISC VIN VIN − VO −40°C < TA < +125°C −40°C < TA < +125°C −40°C < TA < +125°C ILOAD = 0 mA to 10 mA, VIN = 3.5 V, −40°C < TA < +125°C ILOAD = 0 mA to −5 mA, VIN = 3.5 V, −40°C < TA < +125°C No load, −40°C < TA < +125°C 0.1 Hz to 10 Hz 1 kHz −20 2 1 +10 −50 −50 3 1 45 10 50 70 −75 27 1000 hours fIN = 10 kHz 3 500 18 The long-term stability specification is noncumulative. The drift in the subsequent 1000-hour period is significantly lower than in the first 1000-hour period. Rev. A | Page 3 of 20 ADR440/ADR441/ADR443/ADR444/ADR445 ADR441 ELECTRICAL CHARACTERISTICS VIN = 3 V to 18 V, TA = 25°C, CIN = COUT = 0.1 μF, unless otherwise noted. Table 3. Parameter OUTPUT VOLTAGE A Grade B Grade INITIAL ACCURACY A Grade Symbol VO Conditions Min Typ Max Unit 2.497 2.499 2.500 2.500 2.503 2.501 V V 3 0.12 1 0.04 mV % mV % 10 3 20 ppm/°C ppm/°C ppm/V +50 ppm/mA +50 3.75 ppm/mA mA μV p-p nV/√Hz μs ppm ppm dB mA V mV VOERR B Grade TEMPERATURE DRIFT A Grade B Grade LINE REGULATION LOAD REGULATION TCVO ΔVO/ΔVIN ΔVO/ΔILOAD ΔVO/ΔILOAD QUIESCENT CURRENT VOLTAGE NOISE VOLTAGE NOISE DENSITY TURN-ON SETTLING TIME LONG-TERM STABILITY 1 OUTPUT VOLTAGE HYSTERESIS RIPPLE REJECTION RATIO SHORT CIRCUIT TO GND SUPPLY VOLTAGE OPERATING RANGE SUPPLY VOLTAGE HEADROOM 1 IIN eN p-p eN tR VO VO_HYS RRR ISC VIN VIN − VO −40°C < TA < +125°C −40°C < TA < +125°C −40°C < TA < +125°C ILOAD = 0 mA to 10 mA, VIN = 4 V, −40°C < TA < +125°C ILOAD = 0 mA to −5 mA, VIN = 4 V, −40°C < TA < +125°C No load, −40°C < TA < +125°C 0.1 Hz to 10 Hz 1 kHz 2 1 10 −50 −50 3 1.2 48 10 50 70 −75 27 1000 hours fIN = 10 kHz 3 500 18 The long-term stability specification is noncumulative. The drift in subsequent 1000-hour period is significantly lower than in the first 1000-hour period. Rev. A | Page 4 of 20 ADR440/ADR441/ADR443/ADR444/ADR445 ADR443 ELECTRICAL CHARACTERISTICS VIN = 3.5 V to 18 V, TA = 25°C, CIN = COUT = 0.1 μF, unless otherwise noted. Table 4. Parameter OUTPUT VOLTAGE A Grade B Grade INITIAL ACCURACY A Grade Symbol VO Conditions Min Typ Max Unit 2.996 2.9988 3.000 3.000 3.004 3.0012 V V 4 0.13 1.2 0.04 mV % mV % 10 3 20 ppm/°C ppm/°C ppm/V +50 ppm/mA +50 3.75 ppm/mA mA μV p-p nV/√Hz μs ppm ppm dB mA V mV VOERR B Grade TEMPERATURE DRIFT A Grade B Grade LINE REGULATION LOAD REGULATION TCVO ΔVO/ΔVIN ΔVO/ΔILOAD ΔVO/ΔILOAD QUIESCENT CURRENT VOLTAGE NOISE VOLTAGE NOISE DENSITY TURN-ON SETTLING TIME LONG-TERM STABILITY 1 OUTPUT VOLTAGE HYSTERESIS RIPPLE REJECTION RATIO SHORT CIRCUIT TO GND SUPPLY VOLTAGE OPERATING RANGE SUPPLY VOLTAGE HEADROOM 1 IIN eN p-p eN tR VO VO_HYS RRR ISC VIN VIN − VO −40°C < TA < +125°C −40°C < TA < +125°C −40°C < TA < +125°C ILOAD = 0 mA to 10 mA, VIN = 5 V, −40°C < TA < +125°C ILOAD = 0 mA to −5 mA, VIN = 5 V, −40°C < TA < +125°C No load, −40°C < TA < +125°C 0.1 Hz to 10 Hz 1 kHz 2 1 10 −50 −50 3 1.4 57.6 10 50 70 −75 27 1000 hours fIN = 10 kHz 3.5 500 18 The long-term stability specification is noncumulative. The drift in the subsequent 1000-hour period is significantly lower than in the first 1000-hour period. Rev. A | Page 5 of 20 ADR440/ADR441/ADR443/ADR444/ADR445 ADR444 ELECTRICAL CHARACTERISTICS VIN = 4.6 V to 18 V, TA = 25°C, CIN = COUT = 0.1 μF, unless otherwise noted. Table 5. Parameter OUTPUT VOLTAGE A Grade B Grade INITIAL ACCURACY A Grade Symbol VO Conditions Min Typ Max Unit 4.091 4.0944 4.096 4.096 4.101 4.0976 V V 5 0.13 1.6 0.04 mV % mV % 10 3 20 ppm/°C ppm/°C ppm/V +50 ppm/mA +50 3.75 ppm/mA mA μV p-p nV/√Hz μs ppm ppm dB mA V mV VOERR B Grade TEMPERATURE DRIFT A Grade B Grade LINE REGULATION LOAD REGULATION TCVO ΔVO/ΔVIN ΔVO/ΔILOAD ΔVO/ΔILOAD QUIESCENT CURRENT VOLTAGE NOISE VOLTAGE NOISE DENSITY TURN-ON SETTLING TIME LONG-TERM STABILITY 1 OUTPUT VOLTAGE HYSTERESIS RIPPLE REJECTION RATIO SHORT CIRCUIT TO GND SUPPLY VOLTAGE OPERATING RANGE SUPPLY VOLTAGE HEADROOM 1 IIN eN p-p eN tR VO VO_HYS RRR ISC VIN VIN − VO −40°C < TA < +125°C −40°C < TA < +125°C −40°C < TA < +125°C ILOAD = 0 mA to 10 mA, VIN = 5.5 V, −40°C < TA < +125°C ILOAD = 0 mA to −5 mA, VIN = 5.5 V, −40°C < TA < +125°C No load, −40°C < TA < +125°C 0.1 Hz to 10 Hz 1 kHz 2 1 10 −50 −50 3 1.8 78.6 10 50 70 −75 27 1000 hours fIN = 10 kHz 4.6 500 18 The long-term stability specification is noncumulative. The drift in the subsequent 1000-hour period is significantly lower than in the first 1000-hour period. Rev. A | Page 6 of 20 ADR440/ADR441/ADR443/ADR444/ADR445 ADR445 ELECTRICAL CHARACTERISTICS VIN = 5.5 V to 18 V, TA = 25°C, CIN = COUT = 0.1 μF, unless otherwise noted. Table 6. Parameter OUTPUT VOLTAGE A Grade B Grade INITIAL ACCURACY A Grade Symbol VO Conditions Min Typ Max Unit 4.994 4.998 5.000 5.000 5.006 5.002 V V 6 0.12 2 0.04 mV % mV % 10 3 20 ppm/°C ppm/°C ppm/V +50 ppm/mA +50 3.75 ppm/mA mA μV p-p nV/√Hz μs ppm ppm dB mA V mV VOERR B Grade TEMPERATURE DRIFT A Grade B Grade LINE REGULATION LOAD REGULATION TCVO ΔVO/ΔVIN ΔVO/ΔILOAD ΔVO/ΔILOAD QUIESCENT CURRENT VOLTAGE NOISE VOLTAGE NOISE DENSITY TURN-ON SETTLING TIME LONG-TERM STABILITY 1 OUTPUT VOLTAGE HYSTERESIS RIPPLE REJECTION RATIO SHORT CIRCUIT TO GND SUPPLY VOLTAGE OPERATING RANGE SUPPLY VOLTAGE HEADROOM 1 IIN eN p-p eN tR VO VO_HYS RRR ISC VIN VIN − VO −40°C < TA < +125°C −40°C < TA < +125°C −40°C < TA < +125°C ILOAD = 0 mA to 10 mA, VIN = 6.5 V, −40°C < TA < +125°C ILOAD = 0 mA to −5 mA, VIN = 6.5 V, −40°C < TA < +125°C No load, −40°C < TA < +125°C 0.1 Hz to 10 Hz 1 kHz 2 1 10 −50 −50 3 2.25 90 10 50 70 –75 27 1000 hours fIN = 10 kHz 5.5 500 18 The long-term stability specification is noncumulative. The drift in the subsequent 1000-hour period is significantly lower than in the first 1000-hour period. Rev. A | Page 7 of 20 ADR440/ADR441/ADR443/ADR444/ADR445 ABSOLUTE MAXIMUM RATINGS TA = 25°C, unless otherwise noted. THERMAL RESISTANCE Table 7. θJA is specified for the worst-case conditions, that is, a device soldered in a circuit board for surface-mount packages. Parameter Supply Voltage Output Short-Circuit Duration to GND Storage Temperature Range Operating Temperature Range Junction Temperature Range Lead Temperature, Soldering (60 sec) Rating 20 V Indefinite −65°C to +125°C −40°C to +125°C −65°C to +150°C 300°C Table 8. Thermal Resistance Package Type 8-Lead SOIC_N (R-Suffix) 8-Lead MSOP (RM-Suffix) 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. A | Page 8 of 20 θJA 130 190 θJC 43 Unit °C/W °C/W ADR440/ADR441/ADR443/ADR444/ADR445 TYPICAL PERFORMANCE CHARACTERISTICS VIN = 7 V, TA = 25°C, CIN = COUT = 0.1 μF, unless otherwise noted. 2.051 2.5020 2.050 OUTPUT VOLTAGE (V) 2.5010 2.5005 2.5000 2.049 2.048 2.047 2.046 2.4990 –40 05428-003 2.4995 –25 –10 5 20 35 50 65 TEMPERATURE (°C) 80 95 110 2.045 –40 125 –20 0 20 40 60 80 100 120 TEMPERATURE (°C) Figure 3. ADR441 Output Voltage vs. Temperature Figure 6. ADR440 Output Voltage vs. Temperature 5.006 3.0020 3.0015 OUTPUT VOLTAGE (V) 5.004 3.0010 OUTPUT VOLTAGE (V) 05428-042 OUTPUT VOLTAGE (V) 2.5015 UNIT 1 3.0005 UNIT 2 3.0000 UNIT 3 2.9995 5.002 5.000 4.998 2.9990 05428-004 2.9980 –40 –25 –10 5 20 35 50 65 TEMPERATURE (°C) 80 95 110 4.994 –40 125 05428-043 4.996 2.9985 –20 0 20 40 60 80 100 120 TEMPERATURE (°C) Figure 4. ADR443 Output Voltage vs. Temperature Figure 7. ADR445 Output Voltage vs. Temperature 4.0980 4.0 4.0975 4.0965 4.0960 UNIT 2 UNIT 3 4.0955 4.0950 4.0945 4.0940 –40 –25 –10 5 20 35 50 65 TEMPERATURE (°C) 80 95 110 3.5 +125°C –40°C 2.5 2.0 125 Figure 5. ADR444 Output Voltage vs. Temperature +25°C 3.0 05428-006 SUPPLY CURRENT (mA) UNIT 1 05428-005 OUTPUT VOLTAGE (V) 4.0970 4 6 8 10 12 INPUT VOLTAGE (V) 14 16 Figure 8. ADR441 Supply Current vs. Input Voltage Rev. A | Page 9 of 20 18 ADR440/ADR441/ADR443/ADR444/ADR445 10 3.5 LINE REGULATION (ppm/V) SUPPLY CURRENT (mA) 4.0 3.0 2.5 8 6 4 –25 –10 5 20 35 50 65 TEMPERATURE (°C) 80 95 110 0 –40 125 Figure 9. ADR441 Supply Current vs. Temperature 05428-010 2.0 –40 05428-007 2 –25 –10 5 20 35 50 65 TEMPERATURE (°C) 80 95 110 125 Figure 12. ADR441 Line Regulation vs. Temperature 60 3.5 3.4 LOAD REGULATION (ppm/mA) 3.2 3.1 +125°C 3.0 2.9 +25°C 2.8 2.7 –40°C 05428-008 7.3 9.3 11.3 13.3 15.3 INPUT VOLTAGE (V) VIN = 18V 50 ILOAD = 0mA TO 10mA 45 VIN = 6V 40 35 2.6 2.5 5.3 55 17.3 30 –40 19.3 05428-011 SUPPLY CURRENT (mA) 3.3 –25 –10 5 20 35 50 65 TEMPERATURE (°C) 80 95 110 125 Figure 13. ADR441 Load Regulation vs. Temperature Figure 10. ADR445 Supply Current vs. Input Voltage 7 3.25 LINE REGULATIOIN (ppm/V) 3.05 2.95 5 4 3 2 2.85 –25 –10 5 20 35 50 65 TEMPERATURE (°C) 80 95 110 125 1 0 –40 05428-012 2.75 –40 05428-009 QUIESCENT CURRENT (mA) 6 3.15 –25 –10 5 20 35 50 65 TEMPERATURE (°C) 80 95 110 Figure 14. ADR445 Line Regulation vs. Temperature Figure 11. ADR445 Quiescent Current vs. Temperature Rev. A | Page 10 of 20 125 ADR440/ADR441/ADR443/ADR444/ADR445 50 1.0 0.9 20 10 VIN = 6V 0 –10 –20 ILOAD = 0mA TO –5mA –30 –40 –50 –40 –25 –10 5 20 35 50 65 TEMPERATURE (°C) 80 95 110 0.8 +125°C 0.7 0.6 0.5 +25°C 0.4 –40°C 0.3 0.2 05428-016 30 DIFFERENTIAL VOLTAGE (V) ILOAD = 0mA TO +10mA 05428-013 LOAD REGULATION (ppm/mA) 40 0.1 0 –5 125 Figure 15. ADR445 Load Regulation vs. Temperature 0 5 LOAD CURRENT (mA) 10 Figure 18. ADR445 Minimum Input/Output Differential Voltage vs. Load Current 0.7 0.5 NO LOAD 0.4 MINIMUM HEADROOM (V) 0.5 +125°C 0.4 +25°C –40°C 0.3 0.2 0.3 0.2 0.1 05428-014 0.1 0 –10 –5 0 LOAD CURRENT (mA) 5 10 Figure 16. ADR441 Minimum Input/Output Differential Voltage vs. Load Current 0 –40 05428-017 DIFFERENTIAL VOLTAGE (V) 0.6 –25 –10 5 20 35 50 65 TEMPERATURE (°C) 80 95 110 125 Figure 19. ADR445 Minimum Headroom vs. Temperature 0.5 NO LOAD CIN, COUT = 0.1µF VIN = 5V/DIV 0.3 0.2 0.1 –25 –10 5 20 35 50 65 TEMPERATURE (°C) 80 95 110 125 Figure 17. ADR441 Minimum Headroom vs. Temperature VOUT = 1V/DIV TIME = 10µs/DIV Figure 20. ADR441 Turn-On Response Rev. A | Page 11 of 20 05428-018 0 –40 05428-015 MINIMUM HEADROOM (V) 0.4 ADR440/ADR441/ADR443/ADR444/ADR445 CIN, COUT = 0.1µF CIN, COUT = 0.1µF LOAD OFF LOAD ON VIN = 5V/DIV 5mV/DIV TIME = 200µs/DIV TIME = 200µs/DIV 05428-022 05428-019 VOUT = 1V/DIV Figure 24. ADR441 Load Transient Response Figure 21. ADR441 Turn-Off Response CIN = 0.1µF COUT = 10µF CIN = 0.1µF COUT = 10µF LOAD OFF LOAD ON VIN = 5V/DIV 5mV/DIV TIME = 200µs/DIV Figure 22. ADR441 Turn-On Response 05428-023 TIME = 200µs/DIV 05428-020 VOUT = 1V/DIV Figure 25. ADR441 Load Transient Response CIN = 0.1µF COUT = 10µF 2V/DIV 4V 1µV/DIV CH1 p-p 1.18µV TIME = 1s/DIV Figure 23. ADR441 Line Transient Response Figure 26. ADR441 0.1 Hz to 10.0 Hz Voltage Noise Rev. A | Page 12 of 20 05428-024 TIME = 100µs/DIV 05428-021 2mV/DIV ADR440/ADR441/ADR443/ADR444/ADR445 16 14 50µV/DIV CH1 p-p 49µV NUMBER OF PARTS 12 10 8 6 4 150 130 90 70 50 30 10 –10 –30 –50 –70 –90 –110 –130 05428-025 –150 0 TIME = 1s/DIV 110 05428-028 2 DEVIATION (PPM) Figure 30. ADR441 Typical Output Voltage Hysteresis Figure 27. ADR441 10 Hz to 10 kHz Voltage Noise 10 9 CH1 p-p 2.24µV 7 ADR445 6 5 ADR443 4 3 2 ADR441 1 0 05428-026 TIME = 1s/DIV 10 100 1k FREQUENCY (Hz) 10k 05428-029 1µV/DIV OUTPUT IMPEDANCE (Ω) 8 100k Figure 31. Output Impedance vs. Frequency Figure 28. ADR445 0.1 Hz to 10.0 Hz Voltage Noise 0 CH1 p-p 66µV –20 –30 –40 –50 –60 –70 –80 05428-030 50µV/DIV RIPPLE REJECTION RATIO (dB) –10 –90 05428-027 TIME = 1s/DIV –100 100 1k 10k FREQUENCY (Hz) 100k Figure 32. Ripple Rejection Ratio vs. Frequency Figure 29. ADR445 10 Hz to 10 kHz Voltage Noise Rev. A | Page 13 of 20 1M ADR440/ADR441/ADR443/ADR444/ADR445 THEORY OF OPERATION The ADR44x series of references uses a new reference generation technique known as XFET (eXtra implanted junction FET). This technique yields a reference with low dropout, 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. POWER DISSIPATION CONSIDERATIONS 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 it can be closely compensated for by adding a correction term generated in the same fashion as the proportional-to-temperature (PTAT) term used to compensate band gap references. The advantage of an XFET reference is its correction term, which is approximately 20 times lower and requires less correction than that of a band gap reference. Because most of the noise of a band gap reference comes from the temperature compensation circuitry, the XFET results in much lower noise. TJ and TA are the junction and ambient temperatures, respectively. PD is the device power dissipation. θJA is the device package thermal resistance. The ADR44x family of references is guaranteed to deliver load currents to 10 mA with an input voltage that ranges from 3 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 of increases in power dissipation: TJ = PD × θJA + TA where: BASIC VOLTAGE REFERENCE CONNECTIONS The ADR44x family requires a 0.1 μF capacitor on the input and the output for stability. While not required for operation, a 10 μF capacitor at the input can help with line voltage transient performance. VIN 10µF 0.1µF NC 3 GND 4 8 TP 7 NC 6 VOUT TOP VIEW 5 TRIM (Not to Scale) NOTES 1. NC = NO CONNECT 2. TP = TEST PIN (DO NOT CONNECT) (1) where: 0.1µF Figure 34. Basic Voltage Reference Configuration G is the gain of the reciprocal of the divider ratio. ΔVP is the difference in pinch-off voltage between the two JFETs. IPTAT is the positive temperature coefficient correction current. ADR44x devices are created by on-chip adjustment of R2 and R3 to achieve the different voltage option at the reference output. VIN I1 I1 ADR44x VOUT R2 * ΔVP R1 *EXTRA CHANNEL IMPLANT VOUT = G (ΔVP – R1 × IPTAT) R3 GND 05428-033 IPTAT + 2 ADR440/ ADR441/ ADR443/ ADR444/ ADR445 05428-034 TP 1 Figure 33 shows the basic topology of the ADR44x 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 (ΔVP − R1 × I PTAT ) (2) NOISE PERFORMANCE The noise generated by the ADR44x family of references is typically less than 1.4 μV p-p over the 0.1 Hz to 10.0 Hz band for ADR440, ADR441, and ADR443. Figure 26 shows the 0.1 Hz to 10 Hz noise of the ADR441, which is only 1.2 μV p-p. The noise measurement is made with a band-pass filter made of a 2pole high-pass filter with a corner frequency at 0.1 Hz and a 2pole low-pass filter with a corner frequency at 10.0 Hz. 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 20 and Figure 21 show the turn-on and turn-off settling times for the ADR441. Figure 33. Simplified Schematic Device Rev. A | Page 14 of 20 ADR440/ADR441/ADR443/ADR444/ADR445 APPLICATIONS +VDD OUTPUT ADJUSTMENT The ADR44x family features a TRIM pin that allows the user to adjust the output voltage of the part over a limited range. This allows errors from the reference and overall system errors to be trimmed out by connecting a potentiometer between the output and the ground, with the wiper connected to the TRIM pin. Figure 35 shows the optimal trim configuration. R1 allows fine adjustment of the output and is not always required. RP should be sufficiently large so that the maximum output current from the ADR44x is not exceeded. 2 VIN 0.1µF ADR440/ ADR441/ ADR443/ ADR444/ ADR445 +5V VOUT 6 0.1µF GND R1 R2 10kΩ 10kΩ 4 +10V 05428-036 –5V 0.1µF R3 5kΩ 2 –10V VIN VOUT 6 4 R1 100kΩ NEGATIVE REFERENCE RP 10kΩ R2 1kΩ Figure 35. ADR44x Trim Function Using the trim function has a negligible effect on the temperature performance of the ADR44x. However, all resistors need to be low temperature coefficient resistors, or errors can occur. Figure 37 shows how to connect the ADR44x and a standard operational amplifier, such as the OP1177, to provide negative voltage. This configuration provides two main advantages. First, it only requires two devices; therefore, it does not require excessive board space. Second, and more importantly, it does not require any external resistors. This means the performance of this circuit does not rely on choosing low temperature coefficient resistors to ensure accuracy. +VDD 2 BIPOLAR OUTPUTS VIN ADR440/ ADR441/ ADR443/ ADR444/ ADR445 By connecting the output of the ADR44x to the inverting terminal of an operational amplifier, it is possible to obtain both positive and negative reference voltages. Care must be taken when choosing Resistor R1 and Resistor R2 (see Figure 36). They must be matched as closely as possible to ensure minimal differences between the negative and positive outputs. In addition, care must be taken to ensure performance over temperature. Use low temperature coefficient resistors if the circuit is used over temperature; otherwise, differences exist between the two outputs. 6 VOUT GND 4 –VREF –VDD 05428-037 TRIM 5 GND 0.1µF 05428-035 ADR440/ ADR441/ ADR443/ ADR444/ ADR445 Figure 36. ADR44x Bipolar Outputs VO = ±0.5% Figure 37. ADR44x Negative Reference VOUT is at virtual ground, and the negative reference is taken directly from the output of the operational amplifier. If the negative supply voltage is close to the reference output, the operational amplifier must be dual supply and have low offset and rail-to-rail capability. Rev. A | Page 15 of 20 ADR440/ADR441/ADR443/ADR444/ADR445 PROGRAMMABLE VOLTAGE SOURCE PROGRAMMABLE CURRENT SOURCE To obtain different voltages than those offered by the ADR44x, some extra components are needed. In Figure 38, two potentiometers are used to set the desired voltage, while the buffering amplifier provides current drive. The potentiometer connected between VOUT and GND, with its wiper connected to the noninverting input of the operational amplifier, takes care of coarse trim. The second potentiometer, with its wiper connected to the trim terminal of the ADR44x, is used for fine adjustment. Resolution depends on the end-to-end resistance value and the resolution of the selected potentiometer. It is possible to build a programmable current source using a setup similar to the programmable voltage source, as shown in Figure 39. The constant voltage on the gate of the transistor sets the current through the load. Varying the voltage on the gate changes the current. This circuit does not require a dual digital potentiometer. VCC 0.1µF 2 VIN RSENSE ADR440/ ADR441/ ADR443/ ADR444/ ADR445 +VDD 2 VOUT 6 VIN GND 0.1µF 4 ADJ VREF AD5259 VOUT 6 ILOAD R1 R2 10kΩ 10kΩ 05428-038 4 Figure 39. Programmable Current Source HIGH VOLTAGE FLOATING CURRENT SOURCE Figure 38. Programmable Voltage Source For a completely programmable solution, replace the two potentiometers in Figure 38 with one Analog Devices dual digital potentiometer, offered with either an SPI® or an I2C® interface. These interfaces set the position of the wiper on both potentiometers and allow the output voltage to be set. Table 9 lists compatible Analog Devices digital potentiometers. Use the circuit in Figure 40 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. Table 9. Digital Potentiometer Parts Part No. AD5251 AD5207 AD5242 AD5262 AD5282 AD5252 AD5232 AD5235 ADN2850 1 No. of Channels 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 No. of Positions 64.00 256.00 256.00 256.00 256.00 256.00 256.00 1024.00 1024.00 +VS SST111 VISHAY 2 VIN ITF I2C SPI I2C SPI I2C I 2C SPI SPI SPI R (kΩ) 1, 10, 50, 100 10, 50, 100 10, 100, 1M 20, 50, 200 20, 50, 100 1, 10, 50, 100 10, 50, 100 25, 250 25, 250 VDD1 5.5 5.5 5.5 15 15 5.5 5.5 5.5 5.5 Can also use a negative supply. ADR440/ ADR441/ ADR443/ ADR444/ ADR445 VOUT 6 OP90 2N3904 GND 4 –VS Figure 40. Floating Current Source Adding a negative supply to the operational amplifier allows the user also to produce a negative programmable reference, by connecting the reference output to the inverting terminal of the operational amplifier. Choose feedback resistors to minimize errors over temperature. Rev. A | Page 16 of 20 05428-040 GND 05428-039 ADR440/ ADR441/ ADR443/ ADR444/ ADR445 ADR440/ADR441/ADR443/ADR444/ADR445 PRECISION OUTPUT REGULATOR (BOOSTED REFERENCE) VIN 2 VIN 15V VOUT 6 GND 4 COUT 0.1µF RL 200Ω –V CL 1µF VO 05428-041 CIN 0.1µF 2N7002 ADR440/ ADR441/ ADR443/ ADR444/ ADR445 Figure 41. Boosted Output Reference Higher current drive capability can be obtained, without sacrificing accuracy, by using the circuit in Figure 41. The operational amplifier regulates the MOSFET turn-on, forcing VO to equal the VREF. Current is then drawn from VIN, allowing increased current drive capability. The circuit allows a 50 mA load; if higher current drive is required, use a larger MOSFET. For fast transient response, add a buffer at VO to aid with capacitive loading. Rev. A | Page 17 of 20 ADR440/ADR441/ADR443/ADR444/ADR445 OUTLINE DIMENSIONS 5.00 (0.1968) 4.80 (0.1890) 8 5 4.00 (0.1574) 3.80 (0.1497) 1 6.20 (0.2440) 5.80 (0.2284) 4 1.27 (0.0500) BSC 0.25 (0.0098) 0.10 (0.0040) 0.50 (0.0196) × 45° 0.25 (0.0099) 1.75 (0.0688) 1.35 (0.0532) 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-012-AA 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 42. 8-Lead Standard Small Outline Package [SOIC_N] Narrow Body (R-8) Dimensions shown in millimeters and (inches) 3.00 BSC 8 3.00 BSC 1 5 4.90 BSC 4 PIN 1 0.65 BSC 1.10 MAX 0.15 0.00 0.38 0.22 COPLANARITY 0.10 0.23 0.08 8° 0° SEATING PLANE COMPLIANT TO JEDEC STANDARDS MO-187-AA Figure 43. 8-Lead Mini Small Outline Package [MSOP] (RM-8) Dimensions show in millimeters Rev. A | Page 18 of 20 0.80 0.60 0.40 ADR440/ADR441/ADR443/ADR444/ADR445 ORDERING GUIDE Model ADR440ARZ 1 ADR440ARZ-REEL71 ADR440ARMZ1 ADR440ARMZ-REEL71 ADR440BRZ1 ADR440BRZ-REEL71 ADR441ARZ1 ADR441ARZ-REEL71 ADR441ARMZ1 ADR441ARMZ-REEL71 ADR441BRZ1 ADR441BRZ-REEL71 ADR443ARZ1 ADR443ARZ-REEL71 ADR443ARMZ1 ADR443ARMZ-REEL71 ADR443BRZ1 ADR443BRZ-REEL71 ADR444ARZ1 ADR444ARZ-REEL71 ADR444ARMZ1 ADR444ARMZ-REEL71 ADR444BRZ1 ADR444BRZ-REEL71 ADR445ARZ1 ADR445ARZ-REEL71 ADR445ARMZ1 ADR445ARMZ-REEL71 ADR445BRZ1 ADR445BRZ-REEL71 1 Output Voltage (V) 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 Initial Accuracy, ± (mV) (%) 3 0.15 3 0.15 3 0.15 3 0.15 1 0.05 1 0.05 3 0.12 3 0.12 3 0.12 3 0.12 1 0.04 1 0.04 4 0.13 4 0.13 4 0.13 4 0.13 1.2 0.04 1.2 0.04 5 0.13 5 0.13 5 0.13 5 0.13 1.6 0.04 1.6 0.04 6 0.12 6 0.12 6 0.12 6 0.12 2 0.04 2 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 Z = Pb-free part. Rev. A | Page 19 of 20 Package Description 8-Lead SOIC_N 8-Lead SOIC_N 8-Lead MSOP 8-Lead MSOP 8-Lead SOIC_N 8-Lead SOIC_N 8-Lead SOIC_N 8-Lead SOIC_N 8-Lead MSOP 8-Lead MSOP 8-Lead SOIC_N 8-Lead SOIC_N 8-Lead SOIC_N 8-Lead SOIC_N 8-Lead MSOP 8-Lead MSOP 8-Lead SOIC_N 8-Lead SOIC_N 8-Lead SOIC_N 8-Lead SOIC_N 8-Lead MSOP 8-Lead MSOP 8-Lead SOIC_N 8-Lead SOIC_N 8-Lead SOIC_N 8-Lead SOIC_N 8-Lead MSOP 8-Lead MSOP 8-Lead SOIC_N 8-Lead SOIC_N Branding R01 R01 R02 R02 R03 R03 R04 R04 R05 R05 Temperature Range –40°C to +125°C –40°C to +125°C –40°C to +125°C –40°C to +125°C –40°C to +125°C –40°C to +125°C –40°C to +125°C –40°C to +125°C –40°C to +125°C –40°C to +125°C –40°C to +125°C –40°C to +125°C –40°C to +125°C –40°C to +125°C –40°C to +125°C –40°C to +125°C –40°C to +125°C –40°C to +125°C –40°C to +125°C –40°C to +125°C –40°C to +125°C –40°C to +125°C –40°C to +125°C –40°C to +125°C –40°C to +125°C –40°C to +125°C –40°C to +125°C –40°C to +125°C –40°C to +125°C –40°C to +125°C Package Option R-8 R-8 RM-8 RM-8 R-8 R-8 R-8 R-8 RM-8 RM-8 R-8 R-8 R-8 R-8 RM-8 RM-8 R-8 R-8 R-8 R-8 RM-8 RM-8 R-8 R-8 R-8 R-8 RM-8 RM-8 R-8 R-8 ADR440/ADR441/ADR443/ADR444/ADR445 NOTES Purchase of licensed I2C components of Analog Devices or one of its sublicensed Associated Companies conveys a license for the purchaser under the Philips I2C Patent Rights to use these components in an I2C system, provided that the system conforms to the I2C Standard Specification as defined by Philips. ©2006 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D05428-0-9/06(A) Rev. A | Page 20 of 20