Micropower, Low Noise Precision Voltage References with Shutdown ADR390/ADR391/ADR392/ADR395 FEATURES APPLICATIONS Battery-powered instrumentation Portable medical instrumentation Data acquisition systems Industrial process controls Automotive FUNCTIONAL BLOCK DIAGRAM SHDN 1 VIN 2 ADR390/ ADR391/ ADR392/ ADR395 5 GND VOUT (SENSE) 3 (Not to Scale) 4 V OUT (FORCE) 00419-D-001 Compact TSOT-23-5 packages Low temperature coefficient B grade: 9 ppm/°C A grade: 25 ppm/°C Initial accuracy B grade: ±4 mV maximum A grade: ±6 mV maximum Ultralow output noise: 5 µV p-p (0.1 Hz to 10 Hz) Low dropout: 300 mV Low supply current 3 µA maximum in shutdown 120 µA maximum in operation No external capacitor required Output current: 5 mA Wide temperature range −40°C to + 125°C Figure 1. 5-Lead TSOT (UJ Suffix) Table 1. Model ADR390B ADR390A ADR391B ADR391A ADR392B ADR392A ADR395B ADR395A VOUT (V) 2.048 2.048 2.5 2.5 4.096 4.096 5.0 5.0 Temperature Coefficient (ppm/°C) 9 25 9 25 9 25 9 25 Accuracy (mV) ±4 ±6 ±4 ±6 ±5 ±6 ±5 ±6 GENERAL DESCRIPTION The ADR390, ADR391, ADR392, and ADR395 are precision 2.048 V, 2.5 V, 4.096 V, and 5 V band gap voltage references, respectively, featuring low power and high precision in a tiny footprint. Using ADI’s patented temperature drift curvature correction techniques, the ADR39x references achieve a low 9 ppm/°C of temperature drift in the TSOT package. The ADR39x family of micropower, low dropout voltage references provides a stable output voltage from a minimum supply of 300 mV above the output. Their advanced design eliminates the need for external capacitors, which further reduces board space and system cost. The combination of low power operation, small size, and ease of use makes the ADR39x precision voltage references ideally suited for batteryoperated applications. Rev. F 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 © 2005 Analog Devices, Inc. All rights reserved. ADR390/ADR391/ADR392/ADR395 TABLE OF CONTENTS ADR390 Specifications .................................................................... 3 Terminology .......................................................................................8 ADR391 Specifications .................................................................... 4 Typical Performance Characteristics ..............................................9 ADR392 Specifications .................................................................... 5 Theory of Operation ...................................................................... 16 ADR395 Specifications .................................................................... 6 Applications..................................................................................... 17 Absolute Maximum Ratings............................................................ 7 Basic Voltage Reference Connection ....................................... 17 Thermal Resistance ...................................................................... 7 Outline Dimensions ....................................................................... 19 ESD Caution.................................................................................. 7 Ordering Guide .......................................................................... 19 REVISION HISTORY 5/05—Rev. E to Rev. F Changes to Table 5........................................................................... 7 Changes to Figure 2......................................................................... 9 4/04—Rev. D to Rev. E Changes to ADR390—Specifications............................................ 3 Changes to ADR391—Specifications............................................ 4 Changes to ADR392—Specifications............................................ 5 Changes to ADR395—Specifications............................................ 6 4/04—Rev. C to Rev. D Updated Format................................................................ Universal Changes to Title ............................................................................... 1 Changes to Features......................................................................... 1 Changes to Applications ................................................................. 1 Changes to General Description ................................................... 1 Changes to Table 1........................................................................... 1 Changes to ADR390—Specifications............................................ 3 Changes to ADR391—Specifications............................................ 4 Changes to ADR392—Specifications............................................ 5 Changes to ADR395—Specifications............................................ 6 Changes to Absolute Maximum Ratings ...................................... 7 Changes to Thermal Resistance..................................................... 7 Moved ESD Caution........................................................................ 7 Changes to Figure 3, Figure 4, Figure 7, and Figure 8 ................ 9 Changes to Figure 11, Figure 12, Figure 13, and Figure 14...... 10 Changes to Figure 15, Figure 16, Figure 19, and Figure 20...... 11 Changes to Figure 23 and Figure 24............................................ 12 Changes to Figure 27..................................................................... 13 Changes to Ordering Guide ......................................................... 19 Updated Outline Dimensions...................................................... 19 10/02—Rev. B to Rev. C Add parts ADR392 and ADR395 ....................................Universal Changes to Features ........................................................................ 1 Changes to General Description ................................................... 1 Additions to Table I......................................................................... 1 Changes to Specifications............................................................... 2 Changes to Ordering Guide ........................................................... 4 Changes to Absolute Maximum Ratings...................................... 4 New TPCs 3, 4, 7, 8, 11, 12, 15, 16, 19, and 20 ............................ 6 New Figures 4 and 5...................................................................... 13 Deleted A Negative Precision Reference without Precision Resistors Section ............................................ 13 Edits to General-Purpose Current Source Section ................... 13 Updated Outline Dimensions...................................................... 15 5/02—Rev. A to Rev. B Edits to Layout ...................................................................Universal Changes to Figure 6....................................................................... 13 Revision 0: Initial Version Rev. F | Page 2 of 20 ADR390/ADR391/ADR392/ADR395 ADR390 SPECIFICATIONS Electrical characteristics, VIN = 2.5 V to 15 V, TA = 25°C, unless otherwise noted. Table 2. Parameter OUTPUT VOLTAGE TEMPERATURE COEFFICIENT Symbol VO VO VOERR VOERR VOERR VOERR TCVO SUPPLY VOLTAGE HEADROOM LINE REGULATION LOAD REGULATION VIN − VO ∆VO/∆VIN ∆VO/∆ILOAD QUIESCENT CURRENT IIN VOLTAGE NOISE TURN-ON SETTLING TIME LONG-TERM STABILITY1 OUTPUT VOLTAGE HYSTERESIS RIPPLE REJECTION RATIO SHORT CIRCUIT TO GND en p-p tR ∆VO ∆VO_HYS RRR ISC SHUTDOWN PIN Shutdown Supply Current Shutdown Logic Input Current Shutdown Logic Low Shutdown Logic High ISHDN ILOGIC VINL VINH INITIAL ACCURACY 1 Conditions A grade B grade A grade A grade B grade B grade A grade: −40°C < TA < +125°C B grade: −40°C < TA < +125°C Min 2.042 2.044 Typ 2.048 2.048 Max 2.054 2.052 6 0.29 4 0.19 25 9 10 25 60 140 120 140 300 VIN = 2.5 V to 15 V, −40°C < TA < +125°C ILOAD = 0 mA to 5 mA, −40°C < TA < +85°C, VIN = 3 V ILOAD = 0 mA to 5 mA, −40°C < TA < +125°C, VIN = 3 V No load −40°C < TA < +125°C 0.1 Hz to 10 Hz 5 20 50 100 80 25 30 1000 hours fIN = 60 kHz VIN = 5 V VIN = 15 V 3 500 0.8 2.4 The long-term stability specification is noncumulative. The drift of subsequent 1000 hour periods is significantly lower than in the first 1000 hour period. Rev. F | Page 3 of 20 Unit V V mV % mV % ppm/°C ppm/°C mV ppm/V ppm/mA ppm/mA µA µA µV p-p µs ppm ppm dB mA mA µA nA V V ADR390/ADR391/ADR392/ADR395 ADR391 SPECIFICATIONS Electrical characteristics, VIN = 2.8 V to 15 V, TA = 25°C, unless otherwise noted. Table 3. Parameter OUTPUT VOLTAGE INITIAL ACCURACY TEMPERATURE COEFFICIENT Symbol VO VO VOERR VOERR VOERR VOERR TCVO Conditions A grade B grade A grade A grade B grade B grade A grade, −40°C < TA < +125°C Min 2.494 2.496 Typ 2.5 2.5 B grade, −40°C < TA < +125°C SUPPLY VOLTAGE HEADROOM LINE REGULATION LOAD REGULATION VIN − VO ∆VO/∆VIN ∆VO/∆ILOAD QUIESCENT CURRENT IIN VOLTAGE NOISE TURN-ON SETTLING TIME LONG-TERM STABILITY1 OUTPUT VOLTAGE HYSTERESIS RIPPLE REJECTION RATIO SHORT CIRCUIT TO GND enp-p tR ∆VO ∆VO_HYS RRR ISC SHUTDOWN PIN Shutdown Supply Current Shutdown Logic Input Current Shutdown Logic Low Shutdown Logic High ISHDN ILOGIC VINL VINH 1 Max 2.506 2.504 6 0.24 4 0.16 25 Unit V V mV % mV % ppm/°C 9 ppm/°C 300 VIN = 2.8 V to 15 V, −40°C < TA < +125°C ILOAD = 0 mA to 5 mA, −40°C < TA < +85°C, VIN = 3 V ILOAD = 0 mA to 5 mA, −40°C < TA < +125°C, VIN = 3 V No load −40°C < TA < +125°C 0.1 Hz to 10 Hz 10 25 60 140 120 140 5 20 50 100 80 25 30 1000 hours fIN = 60 kHz VIN = 5 V VIN = 15 V 3 500 0.8 2.4 The long-term stability specification is noncumulative. The drift of subsequent 1000 hour periods is significantly lower than in the first 1000 hour period. Rev. F | Page 4 of 20 mV ppm/V ppm/mA ppm/mA µA µA µV p-p µs ppm ppm dB mA mA µA nA V V ADR390/ADR391/ADR392/ADR395 ADR392 SPECIFICATIONS Electrical characteristics, VIN = 4.3 V to 15 V, TA = 25°C, unless otherwise noted. Table 4. Parameter OUTPUT VOLTAGE TEMPERATURE COEFFICIENT Symbol VO VO VOERR VOERR VOERR VOERR TCVO SUPPLY VOLTAGE HEADROOM LINE REGULATION LOAD REGULATION QUIESCENT CURRENT VIN − VO ∆VO/∆VIN ∆VO/∆ILOAD IIN VOLTAGE NOISE TURN-ON SETTLING TIME LONG-TERM STABILITY1 OUTPUT VOLTAGE HYSTERESIS RIPPLE REJECTION RATIO SHORT CIRCUIT TO GND enp-p tR ∆VO ∆VO_HYS RRR ISC SHUTDOWN PIN Shutdown Supply Current Shutdown Logic Input Current Shutdown Logic Low Shutdown Logic High ISHDN ILOGIC VINL VINH INITIAL ACCURACY 1 Conditions A grade B grade A grade A grade B grade B grade A grade, −40°C < TA < +125°C B grade, −40°C < TA < +125°C Min 4.090 4.091 Typ 4.096 4.096 Max 4.102 4.101 6 0.15 5 0.12 25 9 10 25 140 120 140 300 VIN = 4.3 V to 15 V, −40°C < TA < +125°C ILOAD = 0 mA to 5 mA, −40°C < TA < +125°C, VIN = 5 V No load −40°C < TA < +125°C 0.1 Hz to 10 Hz 7 20 50 100 80 25 30 1000 hours fIN = 60 kHz VIN = 5 V VIN = 15 V 3 500 0.8 2.4 The long-term stability specification is noncumulative. The drift of subsequent 1000 hour periods is significantly lower than in the first 1000 hour period. Rev. F | Page 5 of 20 Unit V V mV % mV % ppm/°C ppm/°C mV ppm/V ppm/mA µA µA µV p-p µs ppm ppm dB mA mA µA nA V V ADR390/ADR391/ADR392/ADR395 ADR395 SPECIFICATIONS Electrical characteristics, VIN = 5.3 V to 15 V, TA = 25°C, unless otherwise noted. Table 5. Parameter OUTPUT VOLTAGE TEMPERATURE COEFFICIENT Symbol VO VO VOERR VOERR VOERR VOERR TCVO SUPPLY VOLTAGE HEADROOM LINE REGULATION LOAD REGULATION QUIESCENT CURRENT VIN − VO ∆VO/∆VIN ∆VO/∆ILOAD IIN VOLTAGE NOISE TURN-ON SETTLING TIME LONG-TERM STABILITY1 OUTPUT VOLTAGE HYSTERESIS RIPPLE REJECTION RATIO SHORT CIRCUIT TO GND en p-p tR ∆VO ∆VO_HYS RRR ISC SHUTDOWN PIN Shutdown Supply Current Shutdown Logic Input Current Shutdown Logic Low Shutdown Logic High ISHDN ILOGIC VINL VINH INITIAL ACCURACY 1 Conditions A grade B grade A grade B grade B grade B grade A grade, −40°C < TA < +125°C B grade, −40°C < TA < +125°C Min 4.994 4.995 Typ 5.000 5.000 Max 5.006 5.005 6 0.12 5 0.10 25 9 10 25 140 120 140 300 VIN = 4.3 V to 15 V, −40°C < TA < +125°C ILOAD = 0 mA to 5 mA, −40°C < TA < +125°C, VIN = 6 V No load −40°C < TA < +125°C 0.1 Hz to 10 Hz 8 20 50 100 80 25 30 1, 000 hours fIN = 60 kHz VIN = 5 V VIN = 15 V 3 500 0.8 2.4 The long-term stability specification is noncumulative. The drift of subsequent 1,000 hour periods is significantly lower than in the first 1,000 hour period. Rev. F | Page 6 of 20 Unit V V mV % mV % ppm/°C ppm/°C mV ppm/V ppm/mA µA µA µV p-p µs ppm ppm dB mA mA µA nA V V ADR390/ADR391/ADR392/ADR395 ABSOLUTE MAXIMUM RATINGS THERMAL RESISTANCE At 25°C, unless otherwise noted. Table 6. Parameter Supply Voltage Output Short-Circuit Duration to GND Storage Temperature Range Operating Temperature Range Junction Temperature Range Lead Temperature Range (Soldering, 60 sec) Rating 18 V See derating curves –65°C to +125°C –40°C to +125°C –65°C to +125°C 300°C θJA is specified for the worst-case conditions, that is, θJA is specified for a device soldered in a circuit board for surfacemount packages. Table 7. Thermal Resistance Package Type TSOT-23-5 (UJ-5) θJA 230 Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating only and 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. 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. F | Page 7 of 20 θJC 146 Unit °C/W ADR390/ADR391/ADR392/ADR395 TERMINOLOGY Temperature Coefficient The change of output voltage with respect to operating temperature changes normalized by the output voltage at 25°C. This parameter is expressed in ppm/°C and can be determined by the following equation: VO_HYS [ppm] = VO (25°C ) – VO_TC VO (25°C ) × 10 6 where: VO (25°C) = VO at 25°C VO (T2 ) – VO (T1 ) TCVO [ppm/ °C ] = × 10 6 VO (25°C ) × (T2 – T1 ) VO_TC = VO at 25°C after a temperature cycle from + 25°C to –40°C to +125°C and back to +25°C where: NOTES VO (25°C) = VO at 25°C Input Capacitor Input capacitors are not required on the ADR39x. There is no limit for the value of the capacitor used on the input, but a 1 µF to 10 µF capacitor on the input improves transient response in applications where the supply suddenly changes. An additional 0.1 µF in parallel also helps reduce noise from the supply. VO (T1) = VO at Temperature 1 VO (T2) = VO at Temperature 2 Line Regulation The change in output voltage due to a specified change in input voltage. This parameter accounts for the effects of self-heating. Line regulation is expressed in either percent per volt, partsper-million per volt, or microvolts per volt change in input voltage. Load Regulation The change in output voltage due to a specified change in load current. This parameter accounts for the effects of self-heating. Load regulation is expressed in either microvolts per milliampere, parts-per-million per milliampere, or ohms of dc output resistance. Long-Term Stability Typical shift of output voltage at 25°C on a sample of parts subjected to a test of 1,000 hours at 25°C. Output Capacitor The ADR39x does not require output capacitors for stability under any load condition. An output capacitor, typically 0.1 µF, filters out any low level noise voltage and does not affect the operation of the part. On the other hand, the load transient response can improve with the addition of a 1 µF to 10 µF output capacitor in parallel. A capacitor here acts as a source of stored energy for a sudden increase in load current. The only parameter that degrades by adding an output capacitor is the turn-on time, and it depends on the size of the capacitor chosen. 150 100 ∆VO = VO(t0) – VO(t1) ⎛ V (t ) – VO (t 1 ) ⎞ ∆VO [ppm] = ⎜⎜ O 0 × 10 6 ⎟⎟ V ( t ) O 0 ⎝ ⎠ DRIFT (ppm) 50 where: 0 –50 VO (T0) = VO at 25°C at Time 0 00419-D-002 –100 VO (T1) = VO at 25°C after 1,000 hours operation at 25°C –150 Thermal Hysteresis The change of output voltage after the device is cycled through temperatures from +25°C to –40°C to +125°C and back to +25°C. This is a typical value from a sample of parts put through such a cycle. VO_HYS = VO(25°C) – VO_TC Rev. F | Page 8 of 20 0 100 200 300 400 500 600 TIME (Hours) 700 800 900 1000 Figure 2. ADR391 Typical Long-Term Drift over 1,000 Hours ADR390/ADR391/ADR392/ADR395 TYPICAL PERFORMANCE CHARACTERISTICS 5.006 2.060 5.004 SAMPLE 3 SAMPLE 2 5.002 2.052 VOUT (V) OUTPUT VOLTAGE (V) 2.056 SAMPLE 3 2.048 SAMPLE 2 5.000 SAMPLE 1 4.998 SAMPLE 1 2.044 –5 30 65 TEMPERATURE (°C) 100 4.994 –40 125 Figure 3. ADR390 Output Voltage vs. Temperature 00419-D-006 00419-D-003 2.040 –40 4.996 –5 100 30 65 TEMPERATURE (°C) 125 Figure 6. ADR395 Output Voltage vs. Temperature 140 2.506 SAMPLE 2 +125°C 2.504 120 SUPPLY CURRENT (µA) SAMPLE 1 SAMPLE 3 2.500 2.498 +85°C –40°C 80 00419-D-004 2.494 –40 –5 30 65 TEMPERATURE (°C) 100 40 2.5 125 Figure 4. ADR391 Output Voltage vs. Temperature 00419-D-007 60 2.496 5.0 7.5 10.0 INPUT VOLTAGE (V) 12.5 15.0 Figure 7. ADR390 Supply Current vs. Input Voltage 4.100 140 4.098 120 SUPPLY CURRENT (µA) SAMPLE 3 4.096 SAMPLE 2 4.094 SAMPLE 1 4.092 +85°C 100 +25°C –40°C 80 60 4.090 4.088 –40 00419-D-005 VOUT (V) +25°C 100 0 40 TEMPERATURE (°C) 80 40 2.5 125 Figure 5. ADR392 Output Voltage vs. Temperature 00419-D-008 VOUT (V) 2.502 5.0 7.5 10.0 INPUT VOLTAGE (V) 12.5 Figure 8. ADR391 Supply Current vs. Input Voltage Rev. F | Page 9 of 20 15.0 ADR390/ADR391/ADR392/ADR395 140 180 IL= 0mA TO 5mA 100 +25°C –40°C 80 00419-D-009 60 40 5 7 9 11 INPUT VOLTAGE (V) VIN = 5.0V 140 VIN = 3.0V 120 100 80 –40 15 13 160 Figure 9. ADR392 Supply Current vs. Input Voltage 00419-D-012 SUPPLY CURRENT (µA) 120 LOAD REGULATION (ppm/mA) +125°C –10 20 50 TEMPERATURE (°C) 80 110 125 Figure 12. ADR391 Load Regulation vs. Temperature 90 140 IL= 0mA TO 5mA –40°C 80 40 5.5 00419-D-010 60 7.0 8.5 11.5 10.0 INPUT VOLTAGE (V) 13.0 VIN = 7.5V 70 VIN = 5V 60 50 40 –40 14.5 –5 30 65 TEMPERATURE (°C) 125 100 Figure 13. ADR392 Load Regulation vs. Temperature Figure 10. ADR395 Supply Current vs. Input Voltage 80 120 IL= 0mA TO 5mA IL= 0mA TO 5mA LOAD REGULATION (ppm/mA) 100 80 60 VIN = 3.0V VIN = 5.0V 40 20 0 –40 00419-D-011 LOAD REGULATION (ppm/mA) 00419-D-013 +25°C 100 80 –10 20 50 TEMPERATURE (°C) 80 110 70 VIN = 7.5V VIN = 5V 60 50 40 30 –40 125 Figure 11. ADR390 Load Regulation vs. Temperature 00419-D-014 SUPPLY CURRENT (µA) LOAD REGULATION (ppm/mA) +125°C 120 –5 30 65 TEMPERATURE (°C) 100 Figure 14. ADR395 Load Regulation vs. Temperature Rev. F | Page 10 of 20 125 ADR390/ADR391/ADR392/ADR395 25 14 LINE REGULATION (ppm/V) LINE REGULATION (ppm/V) 12 20 15 10 10 VIN = 5.3V TO 15V 8 6 4 –10 20 50 TEMPERATURE (°C) 80 110 2 00419-D-018 0 –40 00419-D-015 5 0 –40 125 Figure 15. ADR390 Line Regulation vs. Temperature –5 30 65 TEMPERATURE (°C) 125 100 Figure 18. ADR395 Line Regulation vs. Temperature 25 3.0 20 2.8 VIN_MIN (V) 15 10 2.6 –40°C 2.4 +25°C +85°C 2.2 0 –40 00419-D-016 5 –10 20 50 TEMPERATURE (°C) 80 110 2.0 125 00419-D-019 LINE REGULATION (ppm/V) +125°C 0 1 2 3 LOAD CURRENT (mA) 4 5 Figure 19. ADR390 Minimum Input Voltage vs. Load Current Figure 16. ADR391 Line Regulation vs. Temperature 14 3.6 +125°C 12 +85°C VIN_MIN (V) 10 8 VIN = 4.4V TO 15V 6 3.2 +25°C 3.0 –40°C 4 0 –40 –5 30 65 TEMPERATURE (°C) 100 2.6 125 00419-D-020 2.8 2 00419-D-017 LINE REGULATION (ppm/V) 3.4 0 1 2 3 LOAD CURRENT (mA) 4 Figure 20. ADR391 Minimum Input Voltage vs. Load Current Figure 17. ADR392 Line Regulation vs. Temperature Rev. F | Page 11 of 20 5 ADR390/ADR391/ADR392/ADR395 4.8 70 TEMPERATURE: +25°C –40°C +125°C +25°C 60 +125°C 4.6 4.4 FREQUENCY VIN_MIN (V) 50 +25°C –40°C 4.2 40 30 20 4.0 3.8 0 1 4 2 3 LOAD CURRENT (mA) 0 –0.56 5 Figure 21. ADR392 Minimum Input Voltage vs. Load Current 1k VOLTAGE NOISE DENSITY (nV/ Hz) 5.8 VIN_MIN (V) +25°C –40°C 5.0 00419-D-022 4.8 4.6 0 1 2 3 LOAD CURRENT (mA) 0.34 VIN = 5V ADR390 100 10 1k 100 FREQUENCY (Hz) 10k Figure 25. Voltage Noise Density vs. Frequency Figure 22. ADR395 Minimum Input Voltage vs. Load Current 60 0.19 ADR391 5 4 –0.11 –0.26 0.04 VOUT DEVIATION (mV) 00419-D-025 +125°C 5.6 5.2 –0.41 Figure 24. ADR391 VOUT Hysteresis Distribution 6.0 5.4 00419-D-024 00419-D-021 10 0 TEMPERATURE: +25°C –40°C +125°C +25°C 0 50 VOLTAGE (2µV/DIV) 0 0 0 30 0 20 0 –0.24 –0.18 –0.12 –0.06 0 0.06 0.12 VOUT DEVIATION (mV) 0.18 0.24 00419-D-026 0 10 00419-D-023 FREQUENCY 40 0 0 0.30 TIME (1 Sec/DIV) Figure 23. ADR390 VOUT Hysteresis Distribution Figure 26. ADR391 Typical Voltage Noise 0.1 Hz to 10 Hz Rev. F | Page 12 of 20 ADR390/ADR391/ADR392/ADR395 CL = 0nF VLOAD ON LOAD OFF 00419-D-030 VOLTAGE (1V/DIV) VOLTAGE (100µV/DIV) VOUT TIME (200µs/DIV) TIME (10µs/DIV) Figure 27. ADR391 Voltage Noise 10 Hz to 10 kHz Figure 30. ADR391 Load Transient Response CL = 1nF CBYPASS = 0µF VOUT LINE INTERRUPTION VOLTAGE VOLTAGE (1V/DIV) 0.5V/DIV VOUT VLOAD ON 00419-D-028 00419-D-031 1V/DIV LOAD OFF TIME (200µs/DIV) TIME (10µs/DIV) Figure 28. ADR391 Line Transient Response Figure 31. ADR391 Load Transient Response CBYPASS = 0.1µF CL = 100nF VOUT VOLTAGE VOLTAGE (1V/DIV) 0.5V/DIV LINE INTERRUPTION VOUT VLOAD ON 00419-D-032 00419-D-029 1V/DIV LOAD OFF TIME (10µs/DIV) TIME (200µs/DIV) Figure 29. ADR391 Line Transient Response Figure 32. ADR391 Load Transient Response Rev. F | Page 13 of 20 ADR390/ADR391/ADR392/ADR395 RL = 500Ω VIN = 15V 5V/DIV 2V/DIV VOLTAGE VOLTAGE VOUT VIN 2V/DIV VOUT 5V/DIV 00419-D-036 00419-D-033 VIN TIME (20µs/DIV) TIME (200µs/DIV) Figure 33. ADR391 Turn-On Response Time at 15 V Figure 36. ADR391 Turn-On/Turn-Off Response at 5 V VIN = 15V VIN RL = 500Ω CL = 100nF 5V/DIV 2V/DIV VOLTAGE (5V/DIV) VOLTAGE 5V/DIV VIN 00419-D-037 2V/DIV 00419-D-034 VOUT VOUT TIME (40µs/DIV) TIME (200µs/DIV) Figure 37. ADR391 Turn-On/Turn-Off Response at 5 V Figure 34. ADR391 Turn-Off Response at 15 V 80 CBYPASS = 0.1µF 60 40 RIPPLE REJECTION (dB) 2V/DIV VOLTAGE VOUT 5V/DIV 0 –20 –40 –60 00419-D-038 –80 00419-D-035 VIN 20 –100 –120 10 TIME (200µs/DIV) Figure 35. ADR391 Turn-On/Turn-Off Response at 5 V 100 1k 10k FREQUENCY (Hz) 100k Figure 38. Ripple Rejection vs. Frequency Rev. F | Page 14 of 20 1M ADR390/ADR391/ADR392/ADR395 100 90 70 60 CL = 0µF 50 40 30 20 CL = 1µF 10 0 10 100 1k 10k FREQUENCY (Hz) CL = 0.1µF 100k 00419-D-039 OUTPUT IMPEDANCE (Ω) 80 1M Figure 39. Output Impedance vs. Frequency Rev. F | Page 15 of 20 ADR390/ADR391/ADR392/ADR395 THEORY OF OPERATION Band gap references are the high performance solution for low supply voltage and low power voltage reference applications, and the ADR390/ADR391/ADR392/ADR395 are no exception. The uniqueness of these devices lies in the architecture. As shown in Figure 40, the ideal zero TC band gap voltage is referenced to the output, not to ground. Therefore, if noise exists on the ground line, it is greatly attenuated on VOUT. The band gap cell consists of the PNP pair, Q51 and Q52, running at unequal current densities. The difference in VBE results in a voltage with a positive TC, which is amplified by a ratio of 2× DEVICE POWER DISSIPATION CONSIDERATIONS The ADR390/ADR391/ADR392/ADR395 are capable of delivering load currents to 5 mA, with an input voltage that ranges from 2.8 V (ADR391 only) to 15 V. When these devices are used in applications with large input voltages, care should be taken to avoid exceeding the specified maximum power dissipation or junction temperature because it could result in premature device failure. The following formula should be used to calcu-late a device’s maximum junction temperature or dissipation: R58 R54 PD = This PTAT voltage, combined with VBEs of Q51 and Q52, produces a stable band gap voltage. Reduction in the band gap curvature is performed by the ratio of the resistors R44 and R59, one of which is linearly temperature dependent. Precision laser trimming and other patented circuit techniques are used to further enhance the drift performance. VIN Q1 VOUT (FORCE) VOUT (SENSE) R59 R44 SHUTDOWN MODE OPERATION The ADR390/ADR391/ADR392/ADR395 include a shutdown feature that is TTL/CMOS level compatible. A logic low or a zero volt condition on the SHDN pin is required to turn the devices off. During shutdown, the output of the reference becomes a high impedance state, where its potential would then be determined by external circuitry. If the shutdown feature is not used, the SHDN pin should be connected to VIN (Pin 2). R49 R54 Q51 R53 R48 R61 GND 00419-D-040 Q52 R60 θJA In this equation, TJ and TA are, respectively, the junction and ambient temperatures. PD is the device power dissipation, and θJA is the device package thermal resistance. R58 SHDN TJ – TA Figure 40. Simplified Schematic Rev. F | Page 16 of 20 ADR390/ADR391/ADR392/ADR395 APPLICATIONS BASIC VOLTAGE REFERENCE CONNECTION The circuit shown in Figure 41 illustrates the basic configuration for the ADR39x family. Decoupling capacitors are not required for circuit stability. The ADR39x family is capable of driving capacitive loads from 0 µF to 10 µF. However, a 0.1 µF ceramic output capacitor is recommended to absorb and deliver the charge, as required by a dynamic load. SHUTDOWN GND SHDN ADR39x INPUT CB * VIN 0.1µF * CB *NOT REQUIRED OUTPUT 0.1µF 00419-D-041 VOUT(S) VOUT(F) Figure 41. Basic Configuration for the ADR39x Family Stacking Reference ICs for Arbitrary Outputs Some applications may require two reference voltage sources, which are a combined sum of standard outputs. Figure 42 shows how this stacked output reference can be implemented. OUTPUT TABLE U1/U2 2.048 2.5 4.096 5 4.096 5.0 8.192 10 A negative reference can be easily generated by adding an A1 op amp and is configured as shown in Figure 43. VOUTF and VOUTS are 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, low offset, and rail-to-rail if the negative supply voltage is close to the reference output. VIN 2 U2 VIN 1 VOUT(F) SHDN C2 0.1µF VOUT(S) 4 While this concept is simple, a precaution is required. Since the lower reference circuit must sink a small bias current from U2 plus the base current from the series PNP output transistor in U2, either the external load of U1 or R1 must provide a path for this current. If the U1 minimum load is not well defined, the R1 resistor should be used and set to a value that will conservatively pass 600 µA of current with the applicable VOUT1 across it. Note that the two U1 and U2 reference circuits are treated locally as macrocells; each has its own bypasses at input and output for best stability. Both U1 and U2 in this circuit can source dc currents up to their full rating. The minimum input voltage, VIN, is determined by the sum of the outputs, VOUT2, plus the dropout voltage of U2. A Negative Precision Reference without Precision Resistors VOUT1 (V) VOUT2 (V) ADR390/ADR390 ADR391/ADR391 ADR392/ADR392 ADR395/ADR395 Two reference ICs are used, fed from an unregulated input, VIN. The outputs of the individual ICs are simply connected in series, which provides two output voltages, VOUT1 and VOUT2. VOUT1 is the terminal voltage of U1, while VOUT2 is the sum of this voltage and the terminal voltage of U2. U1 and U2 are simply chosen for the two voltages that supply the required outputs (see the Output Table in Figure 42). For example, if both U1 and U2 are ADR391s, VOUT1 is 2.5 V and VOUT2 is 5.0 V. VOUT2 +VDD 3 GND 2 5 VIN 4 V OUT(F) U1 2 VIN VOUT(F) SHDN VOUT(S) 4 VOUT1 1 GND 5 3 GND –VREF A1 00419-D-042 5 SHDN –VDD Figure 42. Stacking Voltage References with the ADR390/ADR391/ADR392/ADR395 Figure 43. Negative Reference Rev. F | Page 17 of 20 00419-D-043 1 C2 0.1µF 3 V OUT(S) ADR390/ADR391/ADR392/ADR395 Many times in low power applications, the need arises for a precision current source that can operate on low supply voltages. ADR390/ADR391/ADR392/ADR395 can be configured as a precision current source. As shown in Figure 45, the circuit configuration is a floating current source with a grounded load. The reference’s output voltage is bootstrapped across RSET, which sets the output current into the load. With this configuration, circuit precision is maintained for load currents in the range from the reference’s supply current, typically 90 µA to approximately 5 mA. The transistor Q2 protects Q1 during short-circuit limit faults by robbing its base drive. The maximum current is ILMAX ≈ 0.6 V/RS VIN R1 4.7kΩ U1 SHDN GND VIN VOUT (FORCE) VOUT (SENSE) Q1 Q2N4921 Q2 Q2N2222 RS ADR39x VIN RL SHDN VOUT IL 00419-D-045 General-Purpose Current Source Figure 45. ADR39x for High Power Performance with Current Limit ADR39x VIN ISET VOUT R1 0.1µF A similar circuit function can also be achieved with the Darlington transistor configuration, as shown in Figure 46. R1 GND ISY (ISET) VIN P1 U1 SHDN GND VIN IOUT = ISET + ISY (ISET) Q2N2222 VOUT (FORCE) 00419-D-044 RL R1 4.7kΩ Q1 Q2 VOUT (SENSE) ADR39x Figure 44. A General-Purpose Current Source Q2N4921 RS RL High Power Performance with Current Limit In some cases, the user may want higher output current delivered to a load and still achieve better than 0.5% accuracy out of the ADR39x. The accuracy for a reference is normally specified on the data sheet with no load. However, the output voltage changes with load current. The circuit shown in Figure 45 provides high current without compromising the accuracy of the ADR39x. The series pass transistor Q1 provides up to 1 A load current. The ADR39x delivers only the base drive to Q1 through the force pin. The sense pin of the ADR39x is a regulated output and is connected to the load. Rev. F | Page 18 of 20 Figure 46. ADR39x for High Output Current with Darlington Drive Configuration 00419-D-046 RSET ISY ADJUST ADR390/ADR391/ADR392/ADR395 OUTLINE DIMENSIONS 2.90 BSC 5 4 2.80 BSC 1.60 BSC 1 2 3 PIN 1 0.95 BSC 1.90 BSC 0.90 0.87 0.84 1.00 MAX 0.10 MAX 0.50 0.30 SEATING PLANE 8° 4° 0.20 0.08 0.60 0.45 0.30 COMPLIANT TO JEDEC STANDARDS MO-193AB Figure 47. 5-Lead Thin Small Outline Transistor Package [TSOT] (UJ-5) Dimensions shown in millimeters ORDERING GUIDE Models ADR390AUJZ-REEL71 ADR390AUJZ-R21 ADR390BUJZ-REEL71 ADR390BUJZ-R21 ADR391AUJZ-REEL71 ADR391AUJZ-R21 ADR391BUJZ-REEL71 ADR391BUJZ-R21 ADR392AUJZ-REEL71 ADR392AUJZ-R21 ADR392BUJZ-REEL71 ADR392BUJZ-R21 ADR395AUJZ-REEL71 ADR395AUJZ-R21 ADR395BUJZ-REEL71 ADR395BUJZ-R21 1 Output Voltage (VO) 2.048 2.048 2.048 2.048 2.5 2.5 2.5 2.5 4.096 4.096 4.096 4.096 5.0 5.0 5.0 5.0 Initial Accuracy (mV) (%) 6 0.29 6 0.29 4 0.19 4 0.19 6 0.24 6 0.24 4 0.16 4 0.16 6 0.15 6 0.15 5 0.12 5 0.12 6 0.12 6 0.12 5 0.10 5 0.10 Temperature Coefficient (ppm/°C) 25 25 9 9 25 25 9 9 25 25 9 9 25 25 9 9 Package Description TSOT TSOT TSOT TSOT TSOT TSOT TSOT TSOT TSOT TSOT TSOT TSOT TSOT TSOT TSOT TSOT Z = Pb-free part. Rev. F | Page 19 of 20 Package Option UJ-5 UJ-5 UJ-5 UJ-5 UJ-5 UJ-5 UJ-5 UJ-5 UJ-5 UJ-5 UJ-5 UJ-5 UJ-5 UJ-5 UJ-5 UJ-5 Branding R0A R0A R0B R0B R1A R1A R1B R1B RCA RCA RCB RCB RDA RDA RDB RDB Number of Parts per Reel 3,000 250 3,000 250 3,000 250 3,000 250 3,000 250 3,000 250 3,000 250 3,000 250 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 ADR390/ADR391/ADR392/ADR395 NOTES © 2005 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. C00419–0–5/05(F) Rev. F | Page 20 of 20