LM185-2.5,LM285-2.5,LM385-2.5 LM185-2.5/LM285-2.5/LM385-2.5 Micropower Voltage Reference Diode Literature Number: SNVS743C LM185-2.5/LM285-2.5/LM385-2.5 Micropower Voltage Reference Diode General Description The LM185-2.5/LM285-2.5/LM385-2.5 are micropower 2-terminal band-gap voltage regulator diodes. Operating over a 20 μA to 20 mA current range, they feature exceptionally low dynamic impedance and good temperature stability. On-chip trimming is used to provide tight voltage tolerance. Since the LM-185-2.5 band-gap reference uses only transistors and resistors, low noise and good long term stability result. Careful design of the LM185-2.5 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 LM185-2.5 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. For applications requiring 1.2V see LM185-1.2. The LM185-2.5 is rated for operation over a −55°C to 125°C temperature range while the LM285-2.5 is rated −40°C to 85° C and the LM385-2.5 0°C to 70°C. The LM185-2.5/LM285-2.5 are available in a hermetic TO-46 package and the LM285-2.5/LM385-2.5 are also available in a low-cost TO-92 molded package, as well as S.O. and SOT-23. The LM185-2.5 is also available in a hermetic leadless chip carrier package. Features ■ ■ ■ ■ ■ ■ ±20 mV (±0.8%) max. initial tolerance (A grade) Operating current of 20 μA to 20 mA 0.6Ω dynamic impedance (A grade) Low temperature coefficient Low voltage reference—2.5V 1.2V device and adjustable device also available— LM185-1.2 series and LM185 series, respectively Connection Diagrams TO-92 Plastic Package SO Package 551908 Bottom View Order Number LM285Z-2.5, LM285BXZ-2.5, LM285BYZ-2.5 LM385Z-2.5, LM385AXZ-2.5 LM385AYZ-2.5, LM385BZ-2.5, LM385BXZ-2.5 or LM385BYZ-2.5 See NS Package Number Z03A 551911 Order Number LM285M-2.5, LM285BXM-2.5, LM285BYM-2.5 LM385M-2.5, LM385BM-2.5 LM385BXM-2.5 or LM385BYM-2.5 See NS Package Number M08A SOT-23 551929 * Pin 3 is attached to the Die Attach Pad (DAP) and should be connected to Pin 2 or left floating. Order Number LM385M3-2.5 See NS Package Number MA03B © 2008 National Semiconductor Corporation 5519 www.national.com LM185-2.5/LM285-2.5/LM385-2.5 Micropower Voltage Reference Diode January 30, 2008 LM185-2.5/LM285-2.5/LM385-2.5 LCC Leadless Chip Carrier TO-46 Metal Can Package 551913 Bottom View Order Number LM185H-2.5, LM185H-2.5/883, LM185BXH-2.5, LM185BXH-2.5/883, LM185BYH-2.5, LM185BYH2.5/883, LM285H-2.5, or LM285BYH-2.5 See NS Package Number H02A 551914 Order Number LM185E-2.5/883 See NS Package Number E20A www.national.com 2 If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Reverse Current Forward Current Operating Temperature Range (Note 3) LM185-2.5 LM285-2.5 LM385-2.5 30 mA 10 mA −55°C to + 125°C −40°C to + 85°C 0°C to 70°C 2kV −55°C to + 150°C 260°C 300°C 215°C 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) Parameter Reverse Breakdown Conditions Typ IR = 100 μA 2.500 Voltage LM385A-2.5 LM385AX-2.5 LM385AY-2.5 Tested Limit (Note 5) 12 V(Min) 2.520 V(Max) V(Min) V(Max) 2.470 2.530 18 20 1 1.5 Current Reverse Breakdown IMIN ≤ IR ≤ 1mA Voltage Change with Current Units (Limits) 2.480 2.500 Minimum Operating Design Limit (Note 6) μA (Max) mV (Max) 1 mA ≤ IR ≤ 20 mA 10 20 mV (Max) Reverse Dynamic IR = 100 μA, Impedance f = 20 Hz Wideband Noise (rms) IR = 100 μA 0.6 0.2 Ω 1.5 120 μV 20 ppm 10 Hz ≤ f ≤ 10 kHz Long Term Stability IR = 100 μA, T = 1000 Hr, TA = 25°C ±0.1°C Average Temperature IMIN ≤ IR ≤ 20 mA Coefficient (Note 7) X Suffix Y Suffix All Others ppm/°C (Max) 30 50 150 3 www.national.com LM185-2.5/LM285-2.5/LM385-2.5 ESD Susceptibility (Note 9) Storage Temperature Soldering Information TO-92 Package (10 sec.) TO-46 Package (10 sec.) SO and SOT Package Vapor Phase (60 sec.) Infrared (15 sec.) Absolute Maximum Ratings (Notes 1, 2) LM185-2.5/LM285-2.5/LM385-2.5 Electrical Characteristics Parameter Conditions LM185-2.5 LM185BX-2.5 LM185BY-2.5 LM285-2.5 LM285BX-2.5 LM285BY-2.5 Typ Tested Limit (Notes 5, 8) Reverse Breakdown Voltage TA = 25°C, 2.5 20 μA ≤ IR ≤ 20 mA Minimum Operating Current LM385M3-2.5 IR = 100 μA, Impedance f = 20 Hz Wideband Noise (rms) IR = 100 μA, Design Limit (Note 6) Tested Limit (Note 5) LM385-2.5 Design Limit (Note 6) Units (Limit) Tested Design Limit Limit (Note 5) (Note 6) 2.462 2.462 2.425 V(Min) 2.538 2.538 2.575 V(Max) 13 20 Reverse 20 μA ≤ IR ≤ 1 mA Breakdown Voltage Change with 1 mA ≤ IR ≤ 20 mA Current Reverse Dynamic LM385B-2.5 LM385BX-2.5 LM385BY-2.5 30 20 30 20 30 15 20 μA (Max) 1 1.5 2.0 2.5 2.0 2.5 mV (Max) 10 20 20 25 20 25 mV (Max) 1 Ω 120 μV 20 ppm 10 Hz ≤ f ≤ 10 kHz Long Term Stability IR = 100 μA, T = 1000 Hr, TA = 25°C ±0.1°C Average IR = 100 μA Temperature Coefficient (Note 7) X Suffix Y Suffix All Others 30 50 30 50 150 150 150 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-2.5 for military specifications. Note 3: For elevated temperature operation, TJ MAX is: LM185 LM285 LM385 150°C 125°C 100°C Thermal Resistance θja (Junction to Ambient) TO-92 TO-46 SO-8 SOT-23 180°C/W (0.4″ Leads) 440°C/W 165°C/W 283°C/W 80°C/W N/A N/A 170°C/W (0.125″ Leads) θjc (Junction to Case) 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 available on request. Note 9: The human body model is a 100 pF capacitor discharged through a 1.5 kΩ resistor into each pin. www.national.com 4 LM185-2.5/LM285-2.5/LM385-2.5 Typical Performance Characteristics Reverse Characteristics Reverse Characteristics 551916 551915 Forward Characteristics Temperature Drift 551917 551918 Reverse Dynamic Impedance Reverse Dynamic Impedance 551919 551920 5 www.national.com LM185-2.5/LM285-2.5/LM385-2.5 Noise Voltage Filtered Output Noise 551922 551921 Response Time 551923 Applications LM385-2.5 Applications Wide Input Range Reference Micropower 5V Reference 551912 Micropower Reference from 9V Battery 551909 Note 10: IQ ≃ 40 μA 551902 www.national.com 6 LM185-2.5/LM285-2.5/LM385-2.5 Micropower 10V Reference 551910 Note 11: IQ ≃ 30 μA standby current PRECISION 1 μA to 1 mA CURRENT SOURCES 551925 551924 7 www.national.com LM185-2.5/LM285-2.5/LM385-2.5 METER THERMOMETERS 0°C–100°C Thermomemter 551926 Calibration 1. Short LM385-2.5, adjust R3 for IOUT=temp at 1μA/°K Remove short, adjust R2 for correct reading in centigrade 0°F–50°F Thermomemter 551927 Calibration 1. Short LM385-2.5, adjust R3 for IOUT=temp at 1.8 μA/°K Remove short, adjust R2 for correct reading in °F www.national.com 8 LM185-2.5/LM285-2.5/LM385-2.5 Micropower Thermocouple Cold Junction Compensator 551906 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. Thermocouple Type Seebeck Coefficient R1 R2 (Ω) (Ω) 52.3 42.8 40.8 S 6.4 Voltage Across R2 (mV) (mV) (μV/°C) J T K Voltage Across R1 @25°C 523 1.24k 432 1k 412 953Ω 63.4 150Ω 15.60 12.77 12.17 14.32 11.78 11.17 1.908 1.766 Typical supply current 50 μA Improving Regulation of Adjstable Regulators 551907 9 www.national.com LM185-2.5/LM285-2.5/LM385-2.5 Schematic Diagram 551901 www.national.com 10 LM185-2.5/LM285-2.5/LM385-2.5 Physical Dimensions inches (millimeters) unless otherwise noted Order Number LM185E-2.5/883 NS Package Number E20A TO-46 Metal Can Package (H) Order Number LM185H-2.5, LM185H-2.5/883, LM185BXH-2.5, LM185BXH-2.5/883, LM185BYH-2.5, LM185BYH-2.5/883, LM285H-2.5, or LM285BYH-2.5 NS Package Number H02A 11 www.national.com LM185-2.5/LM285-2.5/LM385-2.5 SOT-23 Package (M3) Order Number LM385M3-2.5 NS Package Number MA03B www.national.com 12 LM185-2.5/LM285-2.5/LM385-2.5 Small Outline (SO-8) Package (M) Order Number LM285M-2.5, LM285BXM-2.5, LM285BYM-2.5, LM385M-2.5, LM385BM-2.5, LM385BXM-2.5 or LM385BYM-2.5 NS Package Number M08A 13 www.national.com LM185-2.5/LM285-2.5/LM385-2.5 TO-92 Plastic Package (Z) Order Number LM285Z-2.5, LM285BXZ-2.5, LM285BYZ-2.5, LM385Z-2.5, LM385AXZ-2.5, LM385AYZ-2.5, LM385BZ-2.5, LM385BXZ-2.5 or LM385BYZ-2.5 NS Package Number Z03A www.national.com 14 www.national.com 15 LM185-2.5/LM285-2.5/LM385-2.5 Notes LM185-2.5/LM285-2.5/LM385-2.5 Micropower Voltage Reference Diode Notes For more National Semiconductor product information and proven design tools, visit the following Web sites at: Products Design Support Amplifiers www.national.com/amplifiers WEBENCH www.national.com/webench Audio www.national.com/audio Analog University www.national.com/AU Clock Conditioners www.national.com/timing App Notes www.national.com/appnotes Data Converters www.national.com/adc Distributors www.national.com/contacts Displays www.national.com/displays Green Compliance www.national.com/quality/green Ethernet www.national.com/ethernet Packaging www.national.com/packaging Interface www.national.com/interface Quality and Reliability www.national.com/quality LVDS www.national.com/lvds Reference Designs www.national.com/refdesigns Power Management www.national.com/power Feedback www.national.com/feedback Switching Regulators www.national.com/switchers LDOs www.national.com/ldo LED Lighting www.national.com/led PowerWise www.national.com/powerwise Serial Digital Interface (SDI) www.national.com/sdi Temperature Sensors www.national.com/tempsensors Wireless (PLL/VCO) www.national.com/wireless THE CONTENTS OF THIS DOCUMENT ARE PROVIDED IN CONNECTION WITH NATIONAL SEMICONDUCTOR CORPORATION (“NATIONAL”) PRODUCTS. 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