TL/H/5519
LM185-2.5/LM285-2.5/LM385-2.5 Micropower Voltage Reference Diode
December 1994
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
a20mA 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 transis-
tors and resistors, low noise and good long term stability
result.
Careful design of the LM185-2.5 has made the device ex-
ceptionally 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 pur-
pose 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 re-
quiring 1.2V see LM185-1.2.
The LM185-2.5 is rated for operation over a b55§Cto
125§C temperature range while the LM285-2.5 is rated
b40§Cto85
§
C and the LM385-2.5 0§Cto70
§
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. The LM185-25
is also available in a hermetic leadless chip carrier package.
Features
Yg20 mV (g0.8%) max. initial tolerance (A grade)
YOperating current of 20 mAto20mA
Y0.6Xdynamic impedance (A grade)
YLow temperature coefficient
YLow voltage referenceÐ2.5V
Y1.2V device and adjustable device also availableÐ
LM185-1.2 series and LM185 series, respectively
Applications
Wide Input Range Reference
TL/H/551912
Micropower Reference from 9V Battery
TL/H/55192
Connection Diagrams
TO-92
Plastic Package
TL/H/55198
Bottom View
Order Number LM285Z-2.5,
LM285AZ-2.5, LM285AXZ-2.5,
LM285AYZ-2.5,
LM285BXZ-2.5, LM285BYZ-2.5,
LM385Z-2.5, LM385AZ-2.5,
LM385AXZ-2.5, LM385AYZ-2.5,
LM385BZ-2.5, LM385BXZ-2.5
or LM385BYZ-2.5
See NS Package Number Z03A
TO-46
Metal Can Package
TL/H/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, LM285BXH-2.5
or LM285BYH-2.5
See NS Package Number H02A
SO Package
TL/H/551911
Order Number LM285M-2.5,
LM285AM-2.5, LM285AXM-2.5,
LM285AYM-2.5, LM285BXM-2.5,
LM285BYM-2.5, LM385M-2.5,
LM385AM-2.5, LM385AXM-2.5,
LM385AYM-2.5, LM385BM-2.5,
LM385BXM-2.5 or LM385BYM-2.5
See NS Package Number M08A
C1995 National Semiconductor Corporation RRD-B30M75/Printed in U. S. A.
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 30 mA
Forward Current 10 mA
Operating Temperature Range (Note 3)
LM185-2.5 b55§Ctoa125§C
LM285-2.5 b40§Ctoa85§C
LM385-2.5 0§Cto70
§
C
Storage Temperature b55§Ctoa150§C
Soldering Information
TO-92 Package (10 sec.) 260§C
TO-46 Package (10 sec.) 300§C
SO Package
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 sur-
face mount devices.
Electrical Characteristics (Note 4)
Parameter Conditions Typ
LM285A-2.5 LM385A-2.5
(Limits)
Units
LM285AX-2.5 LM385AX-2.5
LM285AY-2.5 LM385AY-2.5
Tested Design Tested Design
Limit Limit Limit Limit
(Notes 5, 8) (Note 6) (Note 5) (Note 6)
Reverse Breakdown IRe100 mA 2.500 2.480 2.480 V(Min)
Voltage 2.520 2.520 V(Max)
2.500 2.460 2.470 V(Min)
2.535 2.530 V(Max)
Minimum Operating 12 18 20 18 20 mA
Current (Max)
Reverse Breakdown IMIN sIRs1mA 1 1.5 11.5 mV
Voltage Change with (Max)
Current 1mAsI
Rs20 mA 10 20 10 20 mV
(Max)
Reverse Dynamic IRe100 mA, 0.2 0.6 0.6 X
Impedance f e20 Hz 1.5 1.5
Wideband Noise (rms) IRe100 mA120 mV
10 Hz sfs10 kHz
Long Term Stability IRe100 mA,
Te1000 Hr, 20 ppm
TAe25§Cg0.1§C
Average Temperature IMIN sIRs20 mA
Coefficient (Note 7) X Suffix 30 30 ppm/§C
Y Suffix 50 50 (Max)
All Others 150 150
2
Electrical Characteristics (Continued) (Note 4)
LM185-2.5
LM185BX-2.5 LM385B-2.5
LM185BY-2.5 LM385BX-2.5 LM385-2.5 Units
LM285-2.5 LM385BY-2.5 (Limit)
Parameter Conditions Typ LM285BX-2.5
LM285BY-2.5
Tested Design Tested Design Tested Design
Limit Limit Limit Limit Limit Limit
(Notes 5, 8) (Note 6) (Note 5) (Note 6) (Note 5) (Note 6)
Reverse Breakdown TAe25§C, 2.5 2.462 2.462 2.425 V(Min)
Voltage 20 mAsIRs20 mA 2.538 2.538 2.575 V(Max)
Minimum Operating 13 20 30 20 30 20 30 mA
Current (Max)
Reverse Breakdown 20 mAsIRs1mA 1 1.5 2.0 2.5 2.0 2.5 mV
Voltage Change with (Max)
Current 1mAsI
Rs20 mA 10 20 20 25 20 25 mV
(Max)
Reverse Dynamic IRe100 mA, 1X
Impedance f e20 Hz
Wideband Noise (rms) IRe100 mA, 120 mV
10 Hz sfs10 kHz
Long Term Stability IRe100 mA,
Te1000 Hr, 20 ppm
TAe25§Cg0.1§C
Average Temperature IRe100 mA
Coefficient (Note 7) X Suffix 30 30 ppm/§C
Y Suffix 50 50 ppm/§C
All Others 150 150 150 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 150§C
LM285 125§C
LM385 100§C
Thermal Resistance TO-92 TO-46 SO-8
ija (Junction to Ambient) 180§C/W (0.4×Leads) 440§C/W 165§C/W
170§C/W (0.125×Leads)
ija (Junction to Case) N/A 80§C/W N/A
Note 4: Parameters identified with boldface type apply at temperature extremes. All other numbers apply at TAeTJe25§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 b55§C, b40§C, 0§C, 25§C, 70§C, 85§C, 125§C.
Note 8: A military RETS electrical specification available on request.
3
Typical Performance Characteristics
Reverse Characteristics Reverse Characteristics Forward Characteristics
Temperature Drift Impedance
Reverse Dynamic
Impedance
Reverse Dynamic
Noise Voltage Filtered Output Noise Response Time
TL/H/55193
Connection Diagram
TL/H/551914
Order Number LM185E-2.5/883
See NS Package Number E20A
4
LM385-2.5 Applications
Micropower*5V Regulator
*IQj40 mATL/H/55199
Micropower*10V Reference
TL/H/551910
*IQj30 mA standby current
Precision 1 mA to 1 mA Current Sources
TL/H/55194
*IOUT e2.5V
R2
METER THERMOMETERS
0§C100§C Thermometer 0§F–50§F Thermometer
TL/H/55195
Calibration
1. Short LM385-2.5, adjust R3 for IOUTetemp at 1mA/§K
2. Remove short, adjust R2 for correct reading in centigrade
Calibration
1. Short LM385-2.5, adjust R3 for IOUTetemp at 1.8 mA/§K
2. Remove short, adjust R2 for correct reading in §F
5
LM385-2.5 Applications (Continued)
Micropower Thermocouple Cold Junction Compensator
TL/H/55196
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.
Seebeck Voltage Voltage
Thermocouple Co- R1 R2 Across R1 Across R2
Type efficient (X)(X)@
25§C(mV)
(mV/§C) (mV)
J 52.3 523 1.24k 15.60 14.32
T 42.8 432 1k 12.77 11.78
K 40.8 412 953X12.17 11.17
S 6.4 63.4 150X1.908 1.766
Typical supply current 50 mA
Improving Regulation of Adjustable
Regulators
TL/H/55197
Schematic Diagram
TL/H/55191
6
Physical Dimensions inches (millimeters)
Order Number LM185E-2.5/883
NS Package Number E20A
7
Physical Dimensions inches (millimeters) (Continued)
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, LM285BXH-2.5 or LM285BYH-2.5
NS Package Number H02A
8
Physical Dimensions inches (millimeters) (Continued)
Small Outline (SO-8) Package (M)
Order Number LM285M-2.5, LM285AM-2.5, LM285AXM-2.5, LM285AYM-2.5,
LM285BXM-2.5, LM285BYM-2.5, LM385M-2.5, LM385AM-2.5, LM385AXM-2.5,
LM385AYM-2.5, LM385BM-2.5, LM385BXM-2.5 or LM385BYM-2.5
NS Package Number M08A
9
LM185-2.5/LM285-2.5/LM385-2.5 Micropower Voltage Reference Diode
Physical Dimensions inches (millimeters) (Continued)
TO-92 Plastic Package (Z)
Order Number LM285Z-2.5, LM285AZ-2.5, LM285AXZ-2.5, LM285AYZ-2.5,
LM285BXZ-2.5, LM285BYZ-2.5, LM385Z-2.5, LM385AZ-2.5, LM385AXZ-2.5,
LM385AYZ-2.5, LM385BZ-2.5, LM385BXZ-2.5 or LM385BYZ-2.5
NS Package Number Z03A
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with instructions for use provided in the labeling, can effectiveness.
be reasonably expected to result in a significant injury
to the user.
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