NSC LM185-1.2 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 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
n
n
n
n
n
n
n
± 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
00551833
00551810
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
© 2004 National Semiconductor Corporation
DS005518
* 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
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LM185-1.2/LM285-1.2/LM385-1.2 Micropower Voltage Reference Diode
May 2003
LM185-1.2/LM285-1.2/LM385-1.2
Connection Diagrams
(Continued)
TO-46
Metal Can Package (H)
SO Package
00551806
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
00551809
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
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2
Storage Temperature
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Soldering Information
(Note 2)
−55˚C to +150˚C
TO-92 package: 10 sec.
260˚C
TO-46 package:10 sec.
300˚C
SO and SOT Pkg.
Reverse Current
30mA
Vapor phase (60 sec.)
215˚C
Forward Current
10mA
Infrared (15 sec.)
220˚C
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
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
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
10µA ≤ IR ≤ 20mA
Minimum Operating
1.235
8
Current
LM385M3-1.2
Reverse Breakdown
10µA ≤ IR ≤ 1mA
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)
1.223
1.223
1.205
V(Min)
1.247
1.247
1.260
V(Max)
10
20
1
1.5
15
1
20
1.5
15
20
µA
10
15
(Max)
1
1.5
Voltage Change
with Current
mV
(Max)
1mA ≤ IR ≤ 20mA
10
20
20
25
20
25
mV
(Max)
Reverse Dynamic
IR = 100µA, f = 20Hz
1
Ω
60
µV
20
ppm
Impedance
Wideband Noise
IR = 100µA,
(rms)
10Hz ≤ f ≤ 10kHz
Long Term Stability
IR = 100µA, T = 1000
Hr,
Average
Temperature
IR = 100µA
Coefficient (Note 7)
X Suffix
30
Y Suffix
50
TA = 25˚C ± 0.1˚C
30
ppm/˚C
50
All Others
150
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
3
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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
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.
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
00551813
00551814
Temperature Drift of 3
Representative Units
Forward Characteristics
00551816
00551815
Reverse Dynamic Impedance
Reverse Dynamic Impedance
00551818
00551817
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LM185-1.2/LM285-1.2/LM385-1.2
Typical Performance Characteristics
(Continued)
Noise Voltage
Filtered Output Noise
00551820
00551819
Response Time
00551821
Typical Applications
Reference from
1.5V Battery
Wide Input
Range Reference
00551823
00551808
Micropower Reference
from 9V Battery
00551822
5
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LM185-1.2/LM285-1.2/LM385-1.2
Typical Applications
(Continued)
Precision 1µA to 1mA Current Sources
Micropower* 5V Regulator
00551826
00551824
*IQ . 30µA
Micropower* 10V Reference
00551827
00551825
*IQ .20µA standby current
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6
(Continued)
METER THERMOMETERS
Micropower Thermocouple Cold Junction
Compensator
0˚C−100˚C Thermometer
00551828
Calibration
1. Short LM385-1.2, adjust R3 for IOUT= temp at 1µA/˚K
2. Remove short, adjust R2 for correct reading in centigrade
00551831
†IQ at 1.3V.500µA
Adjustment Procedure
IQ at 1.6V.2.4mA
1. Adjust TC ADJ pot until voltage across R1 equals Kelvin temperature
multiplied by the thermocouple Seebeck coefficient.
Lower Power Thermometer
2. Adjust zero ADJ pot until voltage across R2 equals the thermocouple
Seebeck coefficient multiplied by 273.2.
Thermocouple
Type
R1 R2
Voltage
Voltage
Coefficient (Ω) (Ω)
Seebeck
Across
R1
Across
R2
@ 25˚C
(mV)
(µV/˚C)
(mV)
J
52.3
5231.24k
15.60
14.32
T
42.8
432 1k
12.77
11.78
*2N3638 or 2N2907 select for inverse HFE . 5
K
40.8
412953Ω
12.17
11.17
†Select for operation at 1.3V
S
6.4
63.4150Ω
1.908
1.766
00551829
‡ IQ . 600µA to 900µA
0˚F−50˚F Thermometer
00551830
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
Typical supply current 50µA
7
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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)
Centigrade Thermometer
00551801
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 volt-
age = 50µA to 150µA
Schematic Diagram
00551807
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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 MF03A
9
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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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10
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LM185-1.2/LM285-1.2/LM385-1.2 Micropower Voltage Reference Diode
Notes
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