LM185/LM285/LM385 Adjustable Micropower Voltage Reference
February 2005
LM185/LM285/LM385 Adjustable Micropower Voltage References
General Description
The LM185/LM285/LM385 are micropower 3-terminal adjustable band-gap voltage reference diodes. Operating from 1.24 to 5.3V and 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 band-gap reference uses only transistors and resistors, low noise and good long-term stability result. Careful design of the LM185 has made the device 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 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 is rated for operation over a −55˚C to 125˚C temperature range, while the LM285 is rated −40˚C to 85˚C and the LM385 0˚C to 70˚C. The LM185 is available in a hermetic TO-46 package and a leadless chip carrier package, while the LM285/LM385 are available in a low-cost TO-92 molded package, as well as S.O.
Features
n n n n n Adjustable from 1.24V to 5.30V Operating current of 10µA to 20mA 1% and 2% initial tolerance 1Ω dynamic impedance Low temperature coefficient
Connection Diagrams
TO-92 Plastic Package TO-46 Metal Can Package
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Bottom View
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Bottom View 20-Leadless Chip Carrier
SOIC Package
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Top View Top View
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© 2005 National Semiconductor Corporation
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LM185/LM285/LM385
Ordering Information
Package −55˚C to 125˚C LM185BH TO-46 LM185BH/883 LM185BYH LM185BYH/883 LM285BXZ TO-92 LM285BYZ LM285Z LM285M LM285BYM LM185BE/883 LM385BXZ LM385BYZ LM385BZ LM385Z 8-Pin SOIC 20-Leadless Chip Carrier LM385M LM385BM M08A E20A Z03A H03H Temperature Range −40˚C to 85˚C 0˚C to 70˚C NSC Drawing
Block Diagram
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Typical Applications
1.2V Reference 5.0V Reference
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LM185/LM285/LM385
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 Forward Current Operating Temperature Range (Note 3) LM185 Series LM285 Series LM385 Series −55˚C to 125˚C −40˚C to 85˚C 0˚C to 70˚C 30mA 10mA
Storage Temperature Soldering Information TO-92 Package (10 sec.) TO-46 Package (10 sec.) SO Package Vapor Phase (60 sec.) Infrared (15 sec.)
−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)
LM185, LM285 LM185BX, LM185BY LM185B, LM285BX, Typ LM285BY Tested Design Tested Design Limit (Note 5) Reference Voltage IR = 100µA 1.240 1.252 1.255 1.228 1.215 Reference Voltage Change with Current Impedance IMIN < IR < 1mA 1mA < IR < 20mA 0.2 4 1 10 1.5 20 1 10 1.5 20 0.2 5 1 15 1.5 25 1 15 1.5 25 1.215 1.205 1.228 1.215 1.215 1.205 Limit (Note 6) Limit (Note 5) 1.265 Limit (Note 6) LM285 Typ Tested Design Tested Design Limit (Note 5) Limit (Note 6) 1.255 Limit (Note 5) 1.265 Limit (Note 6) 1.270 V (max) V (min) mV (max) LM385 LM385BX, LM385BY LM385 Units (Limit)
Parameter
Conditions
1.270 1.240 1.252
Dynamic Output IR = 100µA, f = 100Hz IAC = 0.1 IR VOUT = VREF VOUT = 5.3V Reference Voltage Change with Output Voltage Feedback Current Minimum Operating Current (see curve) Output Wideband Noise VOUT = VREF VOUT = 5.3V IR = 100µA, 10Hz < f < 10kHz VOUT = VREF VOUT = 5.3V 50 170 50 170 µVrms 13 6 30 20 9 45 25 10 50 20 9 45 25 10 50 16 7 35 30 11 55 35 13 60 30 11 55 35 13 60 nA (max) µA (max) IR = 100µA 1 3 6 3 6 2 5 10 5 10 0.3 0.7 0.4 1 Ω
mV (max)
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LM185/LM285/LM385
Electrical Characteristics (Note 4)
(Continued) LM185, LM285 LM385 LM385BX, LM285 Typ Tested Design Tested Design Limit (Note 5) 30 50 150 150 20 150 150 ppm Limit (Note 6) Limit (Note 5) Limit (Note 6) ppm/˚c (max) Limit (Note 5) Limit (Note 6) LM385BY LM385 Units (Limit)
LM185BX, LM185BY LM185B, LM285BX, Typ LM285BY Tested Design Tested Design Limit (Note 5) Average Temperature Coefficient (Note 7) Long Term Stability IR = 100µA X Suffix Y Suffix All Others IR = 100µA, T = 1000 Hr, TA = 25˚C ± 0.1˚C 20 30 50 Limit (Note 6)
Parameter
Conditions
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 for military specifications. Note 3: For elevated temperature operation, TJmax is:
LM185 LM285 LM385 Thermal Resistance θJA (Junction to Ambient) θJC (Junction to Case)
150˚C 125˚C 100˚C TO-92 TO-46 SO-8
180˚C/W (0.4" leads) 170˚C/W (0.125" leads) N/A
440˚C/W 165˚C/W 80˚C/W N/A
Note 4: Parameters identified with boldface type apply at temperature extremes. All other numbers apply at TA = TJ = 25˚C. Unless otherwise specified, all parameters apply for VREF < VOUT < 5.3V. Note 5: Guaranteed and 100% production tested. Note 6: Guaranteed, but not 100% production tested. These limits are not to be 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 from TMIN to TMAX, divided by TMAX − TMIN. The measured temperatures are −55, −40, 0, 25, 70, 85, 125˚C.
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LM185/LM285/LM385
Typical Performance Characteristics
Temperature Drift of 3 Representative Units Feedback Current
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Minimum Operating Current
Reverse Characteristics
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Reverse Characteristics
Forward Characteristics
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LM185/LM285/LM385
Typical Performance Characteristics
Output Noise Voltage
(Continued) Dynamic Output Impedance
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Response Time
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Temperature Coefficient Typical LM185 LM285 LM385
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LM185/LM285/LM385
Typical Applications
Precision 10V Reference Low AC Noise Reference
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25V Low Current Shunt Regulator
200 mA Shunt Regulator
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LM185/LM285/LM385
Typical Applications
(Continued) High Efficiency Low Power Regulator
Series-Shunt 20 mA Regulator
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Voltage Level Detector
Voltage Level Detector
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Fast Positive Clamp 2.4V + ∆VD1
Bidirectional Clamp ± 2.4V
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LM185/LM285/LM385
Typical Applications
(Continued) Bidirectional Adjustable Clamp ± 2.4V to ± 6V
Bidirectional Adjustable Clamp ± 1.8V to ± 2.4V
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Simple Floating Current Detector
Current Source
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LM185/LM285/LM385
Typical Applications
(Continued) Precision Floating Current Detector
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*D1 can be any LED, VF=1.5V to 2.2V at 3 mA. D1 may act as an indicator. D1 will be on if ITHRESHOLD falls below the threshold current, except with I=O.
Centigrade Thermometer, 10mV/˚C
Freezer Alarm
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LM185/LM285/LM385
Schematic Diagram
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LM185/LM285/LM385
Physical Dimensions
unless otherwise noted
inches (millimeters)
20-Leadless Chip Carrier (E) NS Package Number E20A
TO-46 Metal Can Package (H) NS Package Number H03H
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LM185/LM285/LM385
Physical Dimensions
inches (millimeters) unless otherwise noted (Continued)
SO Package (M) NS Package Number M08A
TO-92 Plastic Package (Z) NS Package Number Z03A
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LM185/LM285/LM385 Adjustable Micropower Voltage Reference
Notes
National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications. For the most current product information visit us at www.national.com. LIFE SUPPORT POLICY NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein: 1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body, or (b) support or sustain life, and whose failure to perform when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury to the user. BANNED SUBSTANCE COMPLIANCE National Semiconductor manufactures products and uses packing materials that meet the provisions of the Customer Products Stewardship Specification (CSP-9-111C2) and the Banned Substances and Materials of Interest Specification (CSP-9-111S2) and contain no ‘‘Banned Substances’’ as defined in CSP-9-111S2.
National Semiconductor Americas Customer Support Center Email: new.feedback@nsc.com Tel: 1-800-272-9959 www.national.com National Semiconductor Europe Customer Support Center Fax: +49 (0) 180-530 85 86 Email: europe.support@nsc.com Deutsch Tel: +49 (0) 69 9508 6208 English Tel: +44 (0) 870 24 0 2171 Français Tel: +33 (0) 1 41 91 8790 National Semiconductor Asia Pacific Customer Support Center Email: ap.support@nsc.com National Semiconductor Japan Customer Support Center Fax: 81-3-5639-7507 Email: jpn.feedback@nsc.com Tel: 81-3-5639-7560
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