LM185-1.2

LM185-1.2/LM285-1.2/LM385-1.2 Micropower Voltage Reference Diode January 30, 2008 LM185-1.2/LM285-1.2/LM385-1.2 Micropower Voltage Reference Diode General Description The LM185-1.2/LM285-1.2/LM385-1.2 are micropower 2-terminal band-gap voltage regulator diodes. Operating over a 10μA to 20mA current range, they feature exceptionally low dynamic impedance and good temperature stability. On-chip trimming is used to provide tight voltage tolerance. Since the LM185-1.2 band-gap reference uses only transistors and resistors, low noise and good long term stability result. Careful design of the LM185-1.2 has made the device exceptionally tolerant of capacitive loading, making it easy to use in almost any reference application. The wide dynamic operating range allows its use with widely varying supplies with excellent regulation. The extremely low power drain of the LM185-1.2 makes it useful for micropower circuitry. This voltage reference can be used to make portable meters, regulators or general purpose analog circuitry with battery life approaching shelf life. Further, the wide operating current allows it to replace older references with a tighter tolerance part. The LM185-1.2 is rated for operation over a −55°C to 125°C temperature range while the LM285-1.2 is rated −40°C to 85° C and the LM385-1.2 0°C to 70°C. The LM185-1.2/LM285-1.2 are available in a hermetic TO-46 package and the LM285-1.2/LM385-1.2 are also available in a low-cost TO-92 molded package, as well as SO and SOT-23. The LM185-1.2 is also available in a hermetic leadless chip carrier package. Features ■ ■ ■ ■ ■ ■ ■ ±1% and 2% initial tolerance Operating current of 10μA to 20mA 1Ω dynamic impedance Low temperature coefficient Low voltage reference—1.235V 2.5V device and adjustable device also available LM185-2.5 series and LM185 series, respectively Connection Diagrams T0-92 Plastic Package (Z) SOT23 551833 551810 Bottom View Order Number LM285Z-1.2, LM285BXZ-1.2, LM285BYZ-1.2 LM385Z-1.2, LM385BZ-1.2 LM385BXZ-1.2 or LM385BYZ-1.2 See NS Package Number Z03A SO Package * Pin 3 is attached to the Die Attach Pad (DAP) and should be connected to Pin 2 or left floating. Order Number LM385M3-1.2 See NS Package Number MF03A TO-46 Metal Can Package (H) 551809 551806 Order Number LM285M-1.2, LM285BXM-1.2, LM285BYM-1.2 LM385M-1.2, LM385BM-1.2 LM385BXM-1.2 or LM385BYM-1.2 See NS Package Number M08A Bottom View Order Number LM185H-1.2, LM185H-1.2/883, LM185BXH-1.2, LM185BYH-1.2 LM285H-1.2 or LM285BXH-1.2 See NS Package Number H02A © 2008 National Semiconductor Corporation 5518 www.national.com LM185-1.2/LM285-1.2/LM385-1.2 Absolute Maximum Ratings (Note 1) If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. (Note 2) Reverse Current 30mA Forward Current 10mA Operating Temperature Range (Note 3) LM185-1.2 −55°C to +125°C LM285-1.2 −40°C to +85°C LM385-1.2 0°C to 70°C ESD Susceptibility (Note 9) 2kV Storage Temperature −55°C to +150°C Soldering Information TO-92 package: 10 sec. 260°C TO-46 package:10 sec. 300°C SO and SOT Pkg. Vapor phase (60 sec.) 215°C Infrared (15 sec.) 220°C See AN-450 “Surface Mounting Methods and Their Effect on Product Reliability” for other methods of soldering surface mount devices. Electrical Characteristics (Note 4) LM185-1.2 LM185BX-1.2 LM185BY-1.2 LM285-1.2 LM285BX-1.2 LM285BY-1.2 Tested Design Limit Limit (Notes 5, (Note 6) 8) LM385B-1.2 LM385BX-1.2 LM385BY-1.2 LM385-1.2 Units (Limit) Tested Limit (Note 5) 1.205 1.260 Design Limit (Note 6) V(Min) V(Max) 20 15 1.5 25 μA (Max) mV (Max) mV (Max) Ω μV ppm Parameter Conditions Typ Tested Limit (Note 5) 1.223 1.247 Design Limit (Note 6) Reverse Breakdown Voltage Minimum Operating Current Reverse Breakdown Voltage Change with Current Reverse Dynamic Impedance Wideband Noise (rms) Long Term Stability TA = 25°C, 10μA ≤ IR ≤ 20mA 1.23 5 8 1.223 1.247 10 1 10 20 1.5 20 15 1 20 20 1.5 25 15 10 1 20 LM385M3-1.2 10μA ≤ IR ≤ 1mA 1mA ≤ IR ≤ 20mA IR = 100μA, f = 20Hz IR = 100μA, 10Hz ≤ f ≤ 10kHz IR = 100μA, T = 1000 Hr, TA = 25°C ±0.1°C 20 1 60 Average Temperature IR = 100μA Coefficient (Note 7) X Suffix Y Suffix All Others 30 50 150 30 50 150 150 ppm/°C ppm/°C ppm/°C (Max) Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is intended to be functional, but do not guarantee specific performance limits. For guaranteed specifications and test conditions, see the Electrical Characteristics. The guaranteed specifications apply only for the test conditions listed. Note 2: Refer to RETS185H-1.2 for military specifications. Note 3: For elevated temperature operation, Tj max is: LM185 LM285 LM385 150°C 125°C 100°C www.national.com 2 LM185-1.2/LM285-1.2/LM385-1.2 Thermal Resistance θJA (junction to ambient) θJC (junction to case) TO-92 180°C/W (0.4″ leads) 170°C/W (0.125″ leads) N/A TO-46 440°C/W 80°C/W SO-8 165°C/W N/A SOT23 283°C/W N/A Note 4: Parameters identified with boldface type apply at temperature extremes. All other numbers apply at TA = TJ = 25°C. Note 5: Guaranteed and 100% production tested. Note 6: Guaranteed, but not 100% production tested. These limits are not used to calculate average outgoing quality levels. Note 7: The average temperature coefficient is defined as the maximum deviation of reference voltage at all measured temperatures between the operating TMAX and TMIN, divided by TMAX − TMIN. The measured temperatures are −55°C, −40°C, 0°C, 25°C, 70°C, 85°C, 125°C. Note 8: A military RETS electrical specification is available on request. Note 9: The human body model is a 100 pF capacitor discharged through a 1.5 kΩ resistor into each pin. Typical Performance Characteristics Reverse Characteristics Reverse Characteristics 551813 551814 Forward Characteristics Temperature Drift of 3 Representative Units 551815 551816 3 www.national.com LM185-1.2/LM285-1.2/LM385-1.2 Reverse Dynamic Impedance Reverse Dynamic Impedance 551817 551818 Noise Voltage Filtered Output Noise 551819 551820 Response Time 551821 Typical Applications Wide Input Range Reference Micropower Reference from 9V Battery 551822 Reference from 551808 www.national.com 4 LM185-1.2/LM285-1.2/LM385-1.2 1.5V Battery *IQ ≃20μA standby current Precision 1μA to 1mA Current Sources 551823 Micropower* 5V Regulator 551826 551824 *IQ ≃ 30μA Micropower* 10V Reference 551827 551825 5 www.national.com LM185-1.2/LM285-1.2/LM385-1.2 METER THERMOMETERS 0°C−100°C Thermometer †IQ at 1.3V″500μA IQ at 1.6V″2.4mA Lower Power Thermometer 551829 551828 Calibration 1. Short LM385-1.2, adjust R3 for IOUT= temp at 1μA/°K 2. Remove short, adjust R2 for correct reading in centigrade *2N3638 or 2N2907 select for inverse HFE ″ 5 †Select for operation at 1.3V ‡IQ ≃ 600μA to 900μA 0°F−50°F Thermometer Adjustment Procedure 1. Adjust TC ADJ pot until voltage across R1 equals Kelvin temperature multiplied by the thermocouple Seebeck coefficient. 2. Adjust zero ADJ pot until voltage across R2 equals the thermocouple Seebeck coefficient multiplied by 273.2. Thermocoup Seebeck R1 R2 le Type Coefficient (Ω) (Ω) (μV/°C) J T 551830 Voltage Across R1 @ 25°C (mV) 15.60 12.77 12.17 1.908 Voltage Across R2 (mV) 14.32 11.78 11.17 1.766 52.3 42.8 40.8 6.4 Calibration 1. Short LM385-1.2, adjust R3 for IOUT= temp at 1.8μA/°K 2. Remove short, adjust R2 for correct reading in °F K S 52 3 43 2 41 2 1.2 4k 1k 95 3Ω Micropower Thermocouple Cold Junction Compensator 63. 15 4 0Ω Typical supply current 50μA 551831 www.national.com 6 LM185-1.2/LM285-1.2/LM385-1.2 Centigrade Thermometer 551801 Calibration 1. Adjust R1 so that V1 = temp at 1mV/°K 2. Adjust V2 to 273.2mV †IQ for 1.3V to 1.6V battery voltage = 50μA to 150μA Schematic Diagram 551807 7 www.national.com LM185-1.2/LM285-1.2/LM385-1.2 Physical Dimensions inches (millimeters) unless otherwise noted TO-46 Metal Can Package (H) Order Number LM185H-1.2, LM185H-1.2/883, LM185BXH-1.2, LM185BYH-1.2, LM285H-1.2, or LM285BXH-1.2 NS Package Number H02A SOT-23 Package (M3) Order Number LM385M3-1.2 NS Package Number MF03A www.national.com 8 LM185-1.2/LM285-1.2/LM385-1.2 Small Outline (SO-8) Package Order Number LM285M-1.2, LM285BXM-1.2, LM285BYM-1.2 LM385M-1.2, LM385BM-1.2, LM385BXM-1.2, LM385BYM-1.2 NS Package Number M08A TO-92 Plastic Package (Z) Order Number LM285Z-1.2, LM285BXZ-1.2 LM285BYZ-1.2, LM385Z-1.2, LM385BZ-1.2 LM385BXZ-1.2 or LM385BYZ-1.2 NS Package Number Z03A 9 www.national.com LM185-1.2/LM285-1.2/LM385-1.2 Micropower Voltage Reference Diode Notes For more National Semiconductor product information and proven design tools, visit the following Web sites at: Products Amplifiers Audio Clock Conditioners Data Converters Displays Ethernet Interface LVDS Power Management Switching Regulators LDOs LED Lighting PowerWise Serial Digital Interface (SDI) Temperature Sensors Wireless (PLL/VCO) www.national.com/amplifiers www.national.com/audio www.national.com/timing www.national.com/adc www.national.com/displays www.national.com/ethernet www.national.com/interface www.national.com/lvds www.national.com/power www.national.com/switchers www.national.com/ldo www.national.com/led www.national.com/powerwise www.national.com/sdi www.national.com/tempsensors www.national.com/wireless WEBENCH Analog University App Notes Distributors Green Compliance Packaging Design Support www.national.com/webench www.national.com/AU www.national.com/appnotes www.national.com/contacts www.national.com/quality/green www.national.com/packaging www.national.com/quality www.national.com/refdesigns www.national.com/feedback Quality and Reliability Reference Designs Feedback THE CONTENTS OF THIS DOCUMENT ARE PROVIDED IN CONNECTION WITH NATIONAL SEMICONDUCTOR CORPORATION (“NATIONAL”) PRODUCTS. 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