NSC LM285M-1.2 Micropower voltage reference diode Datasheet

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 10 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 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
n
n
n
n
n
n
n
± 4 mV ( ± 0.3%) max. initial tolerance (A grade)
Operating current of 10 µA to 20 mA
0.6Ω max dynamic impedance (A grade)
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
SOT23
T0-92
Plastic Package (Z)
DS005518-33
* Pin 3 is attached to the Die Attach Pad (DAP) and should be connected
to Pin 2 or left floating.
DS005518-10
Order Number LM385M3-1.2
See NS Package Number MA03B
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
© 2000 National Semiconductor Corporation
DS005518
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LM185-1.2/LM285-1.2/LM385-1.2 Micropower Voltage Reference Diode
January 2000
LM185-1.2/LM285-1.2/LM385-1.2
Connection Diagrams
(Continued)
SO Package
DS005518-9
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
TO-46
Metal Can Package (H)
DS005518-6
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
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2
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.
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)
LM185-1.2
LM285-1.2
LM385-1.2
30 mA
10 mA
−55˚C to +125˚C
−40˚C to +85˚C
0˚C to 70˚C
Electrical Characteristics (Note 4)
LM185-1.2
Parameter
Conditions
Typ
LM185BX-1.2
LM385B-1.2
LM185BY-1.2
LM385BX-1.2
LM285-1.2
LM385BY-1.2
LM385-1.2
Units
LM285BX-1.2
(Limit)
LM285BY-1.2
Reverse Breakdown
TA = 25˚C,
Voltage
10 µA ≤ IR ≤ 20 mA
1.235
Minimum Operating
8
Current
LM385M3-1.2
Reverse Breakdown
10 µA ≤ IR ≤ 1 mA
Tested
Design
Tested
Design
Tested
Limit
Limit
Limit
Limit
Limit
Design
Limit
(Notes
5, 8)
(Note 6)
(Note 5)
(Note 6)
(Note 5)
(Note 6)
1.223
1.223
1.205
V(Min)
1.247
1.247
1.260
V(Max)
10
1
20
15
1.5
1
20
1.5
15
20
µA
10
15
(Max)
1
1.5
Voltage Change
1 mA ≤ IR ≤ 20 mA
with Current
mV
(Max)
10
20
20
25
20
25
mV
(Max)
IR = 100 µA, f = 20 Hz
1
Ω
Wideband Noise
IR = 100 µA,
60
µV
(rms)
10 Hz ≤ f ≤ 10 kHz
20
ppm
Reverse Dynamic
Impedance
Long Term Stability
IR = 100 µA, T = 1000 Hr,
TA = 25˚C ± 0.1˚C
Average Temperature
Coefficient (Note 7)
IR = 100 µA
X Suffix
30
30
Y Suffix
50
50
All Others
150
ppm/˚C
ppm/˚C
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-1.2 for military specifications.
Note 3: For elevated temperature operation, Tj max is:
LM185
150˚C
LM285
125˚C
LM385
100˚C
Thermal Resistance
θJA (junction to ambient)
TO-92
TO-46
SO-8
SOT23
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.
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LM185-1.2/LM285-1.2/LM385-1.2
Absolute Maximum Ratings (Note 1)
LM185-1.2/LM285-1.2/LM385-1.2
Electrical Characteristics (Note 4)
(Continued)
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.
Typical Performance Characteristics
Reverse Characteristics
Reverse Characteristics
DS005518-13
Temperature Drift of 3
Representative Units
Forward Characteristics
DS005518-14
Reverse Dynamic Impedance
DS005518-15
Reverse Dynamic Impedance
DS005518-18
DS005518-17
DS005518-16
Noise Voltage
Filtered Output Noise
DS005518-20
DS005518-19
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Response Time
4
DS005518-21
Wide Input
Range Reference
Micropower Reference
from 9V Battery
Reference from
1.5V Battery
DS005518-22
DS005518-23
DS005518-8
Micropower* 5V Regulator
Micropower* 10V Reference
DS005518-25
*IQ ≅ 20 µA standby current
DS005518-24
*IQ ≅ 30 µA
Precision 1 µA to 1 mA Current Sources
DS005518-27
DS005518-26
5
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LM185-1.2/LM285-1.2/LM385-1.2
Typical Applications
LM185-1.2/LM285-1.2/LM385-1.2
Typical Applications
(Continued)
METER THERMOMETERS
Lower Power Thermometer
0˚C−100˚C Thermometer
DS005518-29
*2N3638 or 2N2907 select for inverse HFE ≅ 5
†Select for operation at 1.3V
‡ IQ ≅ 600 µA to 900 µA
DS005518-28
Calibration
1. Short LM385-1.2, adjust R3 for IOUT = temp at 1 µA/˚K
2. Remove short, adjust R2 for correct reading in centigrade
†IQ at 1.3V ≅ 500 µA
IQ at 1.6V ≅ 2.4 mA
0˚F−50˚F Thermometer
Micropower Thermocouple Cold Junction
Compensator
DS005518-30
Calibration
1. Short LM385-1.2, adjust R3 for IOUT = temp at 1.8 µA/˚K
2. Remove short, adjust R2 for correct reading in ˚F
DS005518-31
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
Seebeck
R1
R2
Voltage
Voltage
Type
Coefficient
(Ω)
(Ω)
Across R1
Across R2
@ 25˚C
(mV)
(µV/˚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 953Ω
12.17
11.17
S
6.4
63.4 150Ω
1.908
1.766
Typical supply current 50 µA
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LM185-1.2/LM285-1.2/LM385-1.2
Typical Applications
(Continued)
Centigrade Thermometer
DS005518-1
Calibration
1. Adjust R1 so that V1 = temp at 1 mV/˚K
2. Adjust V2 to 273.2 mV
†IQ for 1.3V to 1.6V battery voltage = 50 µA to 150 µA
Schematic Diagram
DS005518-7
7
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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 MA03B
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8
LM185-1.2/LM285-1.2/LM385-1.2
Physical Dimensions
inches (millimeters) unless otherwise noted (Continued)
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
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LM185-1.2/LM285-1.2/LM385-1.2 Micropower Voltage Reference Diode
Notes
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