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
■
■
■
■
■
■
■
±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
551833
551810
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
SO Package
Order Number LM385M3-1.2
See NS Package Number MF03A
TO-46
Metal Can Package (H)
551809
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
© 2008 National Semiconductor Corporation
* Pin 3 is attached to the Die Attach Pad (DAP) and should be connected to
Pin 2 or left floating.
5518
551806
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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LM185-1.2/LM285-1.2/LM385-1.2 Micropower Voltage Reference Diode
January 30, 2008
LM185-1.2/LM285-1.2/LM385-1.2
ESD Susceptibility (Note 9)
2kV
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.
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
30mA
Forward Current
10mA
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
Electrical Characteristics
Parameter
(Note 4)
Conditions
Typ
LM185-1.2
LM185BX-1.2
LM185BY-1.2
LM285-1.2
LM285BX-1.2
LM285BY-1.2
Tested
Design
Limit
Limit
(Notes 5, (Note 6)
8)
Reverse Breakdown
TA = 25°C,
Voltage
10μA ≤ IR ≤ 20mA
Minimum Operating
1.23
5
8
LM385B-1.2
LM385BX-1.2
LM385BY-1.2
Tested
Limit
(Note 5)
Design
Limit
(Note 6)
LM385-1.2
Units
(Limit)
Tested
Limit
(Note 5)
Design
Limit
(Note 6)
1.223
1.223
1.205
V(Min)
1.247
1.247
1.260
V(Max)
10
20
15
20
15
20
10
15
μA
(Max)
mV
Current
LM385M3-1.2
Reverse Breakdown
10μA ≤ IR ≤ 1mA
1
1.5
1
1.5
1
1.5
with Current
1mA ≤ IR ≤ 20mA
10
20
20
25
20
25
Reverse Dynamic
IR = 100μA, f = 20Hz
1
Ω
Wideband Noise
IR = 100μA,
60
μV
(rms)
10Hz ≤ f ≤ 10kHz
Long Term Stability
IR = 100μA, T = 1000 Hr,
20
ppm
Voltage Change
(Max)
mV
(Max)
Impedance
TA = 25°C ±0.1°C
Average Temperature IR = 100μA
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-1.2 for military specifications.
Note 3: For elevated temperature operation, Tj max is:
LM185
LM285
LM385
150°C
125°C
100°C
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2
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.
Note 9: The human body model is a 100 pF capacitor discharged through a 1.5 kΩ resistor into each pin.
Typical Performance Characteristics
Reverse Characteristics
Reverse Characteristics
551813
551814
Forward Characteristics
Temperature Drift of 3
Representative Units
551815
551816
3
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LM185-1.2/LM285-1.2/LM385-1.2
Thermal Resistance
θJA (junction to ambient)
LM185-1.2/LM285-1.2/LM385-1.2
Reverse Dynamic Impedance
Reverse Dynamic Impedance
551818
551817
Noise Voltage
Filtered Output Noise
551820
551819
Response Time
551821
Micropower Reference
from 9V Battery
Typical Applications
Wide Input
Range Reference
551822
Reference from
551808
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4
LM185-1.2/LM285-1.2/LM385-1.2
*IQ ≃20μA standby current
1.5V Battery
Precision 1μA to 1mA Current Sources
551823
Micropower* 5V Regulator
551826
551824
*IQ ≃ 30μA
Micropower* 10V Reference
551827
551825
5
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LM185-1.2/LM285-1.2/LM385-1.2
METER THERMOMETERS
0°C−100°C Thermometer
†IQ at 1.3V″500μA
IQ at 1.6V″2.4mA
Lower Power Thermometer
551829
*2N3638 or 2N2907 select for inverse HFE ″ 5
†Select for operation at 1.3V
‡IQ ≃ 600μA to 900μA
551828
Calibration
1. Short LM385-1.2, adjust R3 for IOUT= temp at 1μA/°K
2. Remove short, adjust R2 for correct reading in centigrade
0°F−50°F Thermometer
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.
Thermocoup Seebeck R1 R2
le
Type
Coefficient (Ω) (Ω)
Voltage
Voltage
Across
R1
@ 25°C
Across
R2
(mV)
(mV)
15.60
14.32
12.77
11.78
95
3Ω
12.17
11.17
63. 15
4 0Ω
1.908
1.766
(μV/°C)
J
52.3
T
42.8
K
40.8
S
6.4
551830
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
Micropower Thermocouple Cold Junction Compensator
Typical supply current 50μA
551831
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6
52
3
43
2
41
2
1.2
4k
1k
LM185-1.2/LM285-1.2/LM385-1.2
Centigrade Thermometer
551801
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 voltage = 50μA to 150μA
Schematic Diagram
551807
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 MF03A
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8
LM185-1.2/LM285-1.2/LM385-1.2
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
9
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LM185-1.2/LM285-1.2/LM385-1.2 Micropower Voltage Reference Diode
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