NSC LM285M-2.5 Micropower voltage reference diode Datasheet

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 a 20 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 LM-185-2.5 band-gap reference uses only
transistors and resistors, low noise and good long term
stability result.
Careful design of the LM185-2.5 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 LM185-2.5 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. For applications
requiring 1.2V see LM185-1.2.
The LM185-2.5 is rated for operation over a −55˚C to 125˚C
temperature range while the LM285-2.5 is rated −40˚C to
85˚C and the LM385-2.5 0˚C to 70˚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. and SOT-23. The
LM185-2.5 is also available in a hermetic leadless chip
carrier package.
Features
n
n
n
n
n
n
± 20 mV ( ± 0.8%) max. initial tolerance (A grade)
Operating current of 20 µA to 20 mA
0.6Ω dynamic impedance (A grade)
Low temperature coefficient
Low voltage reference — 2.5V
1.2V device and adjustable device also
available — LM185-1.2 series and LM185 series,
respectively
Connection Diagrams
TO-92
Plastic Package
SO Package
00551908
Bottom View
Order Number LM285Z-2.5,
LM285BXZ-2.5, LM285BYZ-2.5
LM385Z-2.5, LM385AXZ-2.5
LM385AYZ-2.5, LM385BZ-2.5,
LM385BXZ-2.5 or LM385BYZ-2.5
See NS Package Number Z03A
00551911
Order Number LM285M-2.5,
LM285BXM-2.5, LM285BYM-2.5
LM385M-2.5, LM385BM-2.5
LM385BXM-2.5 or LM385BYM-2.5
See NS Package Number M08A
SOT-23
00551929
* Pin 3 is attached to the Die Attach Pad (DAP) and should be connected to Pin 2 or left floating.
Order Number LM385M3-2.5
See NS Package Number MA03B
© 2005 National Semiconductor Corporation
DS005519
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LM185-2.5/LM285-2.5/LM385-2.5 Micropower Voltage Reference Diode
February 2005
LM185-2.5/LM285-2.5/LM385-2.5
Connection Diagrams
(Continued)
LCC
Leadless Chip Carrier
TO-46
Metal Can Package
00551913
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,
or LM285BYH-2.5
See NS Package Number H02A
00551914
Order Number LM185E-2.5/883
See NS Package Number E20A
www.national.com
2
LM385-2.5
(Notes 1,
0˚C to 70˚C
2)
Storage Temperature
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Soldering Information
Reverse Current
30 mA
Forward Current
10 mA
−55˚C to + 125˚C
LM285-2.5
−40˚C to + 85˚C
TO-92 Package (10 sec.)
260˚C
TO-46 Package (10 sec.)
300˚C
SO and SOT Package
Operating Temperature
Range (Note 3)
LM185-2.5
−55˚C to + 150˚C
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.
Electrical Characteristics
(Note 4)
LM385A-2.5
LM385AX-2.5
Parameter
Reverse Breakdown
Conditions
Typ
IR = 100 µA
2.500
Voltage
LM385AY-2.5
Tested
Design
Limit
Limit
(Note 5)
(Note 6)
2.480
V(Min)
2.520
2.500
Minimum Operating
12
18
V(Max)
2.470
V(Min)
2.530
V(Max)
20
Current
Reverse Breakdown
µA
(Max)
IMIN ≤ IR ≤ 1mA
1
1.5
1 mA ≤ IR ≤ 20 mA
10
20
Voltage Change with
Current
Units
(Limits)
mV
(Max)
mV
(Max)
Reverse Dynamic
IR = 100 µA,
Impedance
f = 20 Hz
Wideband Noise (rms)
IR = 100 µA
0.2
0.6
Ω
1.5
120
µV
20
ppm
10 Hz ≤ f ≤ 10 kHz
Long Term Stability
IR = 100 µA,
T = 1000 Hr,
TA = 25˚C ± 0.1˚C
Average Temperature
IMIN ≤ IR ≤ 20 mA
Coefficient (Note 7)
X Suffix
30
Y Suffix
50
All Others
ppm/˚C
(Max)
150
3
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LM185-2.5/LM285-2.5/LM385-2.5
Absolute Maximum Ratings
LM185-2.5/LM285-2.5/LM385-2.5
Electrical Characteristics
LM185-2.5
Parameter
Conditions
Typ
LM185BX-2.5
LM385B-2.5
LM185BY-2.5
LM385BX-2.5
LM285-2.5
LM385BY-2.5
LM385-2.5
Units
(Limit)
LM285BX-2.5
LM285BY-2.5
Tested
Reverse
Breakdown
TA = 25˚C,
Voltage
20 µA ≤ IR ≤ 20
mA
Minimum
Operating
Current
2.5
13
Design
Tested
Design
Tested Design
Limit
Limit
Limit
Limit
Limit
Limit
(Note 5) (Note
8)
(Note
6)
(Note
5)
(Note 6)
(Note
5)
(Note
6)
2.462
2.462
2.425
V(Min)
2.538
2.538
2.575
V(Max)
20
30
20
30
LM385M3-2.5
Reverse
Breakdown
Voltage Change
with Current
20
30
15
20
µA
(Max)
20 µA ≤ IR ≤ 1
mA
1
1.5
2.0
2.5
2.0
2.5
mV
(Max)
1 mA ≤ IR ≤ 20
mA
10
20
20
25
20
25
mV
(Max)
Reverse
Dynamic
IR = 100 µA,
Impedance
f = 20 Hz
Wideband
Noise (rms)
IR = 100 µA,
1
Ω
120
µV
20
ppm
10 Hz ≤ f ≤ 10
kHz
IR = 100 µA,
Long Term
Stability
T = 1000 Hr,
TA = 25˚C
± 0.1˚C
Average
Temperature
IR = 100 µA
Coefficient
(Note 7)
X Suffix
30
Y Suffix
50
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-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
θja (Junction to Ambient)
TO-92
180˚C/W (0.4" Leads)
TO-46
SO-8
SOT-23
440˚C/W 165˚C/W 283˚C/W
170˚C/W (0.125" Leads)
θjc (Junction to Case)
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N/A
80˚C/W
4
N/A
N/A
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 available on request.
Typical Performance Characteristics
Reverse Characteristics
Reverse Characteristics
00551916
00551915
Forward Characteristics
Temperature Drift
00551917
00551918
Reverse Dynamic
Impedance
Reverse Dynamic
Impedance
00551919
00551920
5
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LM185-2.5/LM285-2.5/LM385-2.5
Note 4: Parameters identified with boldface type apply at temperature extremes. All other numbers apply at TA = TJ = 25˚C.
LM185-2.5/LM285-2.5/LM385-2.5
Typical Performance Characteristics
(Continued)
Noise Voltage
Filtered Output Noise
00551922
00551921
Response Time
00551923
Applications
LM385-2.5 Applications
Wide Input Range Reference
Micropower 5V Reference (Note 9)
00551912
Micropower Reference from 9V Battery
00551909
Note 9: IQ . 40 µA
00551902
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6
LM185-2.5/LM285-2.5/LM385-2.5
LM385-2.5 Applications
(Continued)
Micropower 10V Reference (Note 10)
00551910
Note 10: IQ . 30 µA standby current
Precision 1 µA to 1 mA Current Sources
00551925
00551924
7
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LM185-2.5/LM285-2.5/LM385-2.5
LM385-2.5 Applications
(Continued)
METER THERMOMETERS
0˚C–100˚C Thermomemter
Micropower Thermocouple Cold Junction
Compensator
00551926
Calibration
1. Short LM385-2.5, adjust R3 for IOUT=temp at 1µA/˚K
2. Remove short, adjust R2 for correct reading in
centigrade
00551906
Adjustment Procedure
1. Adjust TC ADJ pot until voltage across R1 equals Kelvin
temperature multiplied by the thermocouple Seebeck
coefficient.
0˚F–50˚F Thermomemter
2.
Adjust zero ADJ pot until voltage across R2 equals the
thermocouple Seebeck coefficient multiplied by 273.2.
00551927
Calibration
1. Short LM385-2.5, adjust R3 for IOUT=temp at 1.8 µA/˚K
2. Remove short, adjust R2 for correct reading in ˚F
Voltage
Voltage
Thermocouple
Seebeck
Co-
R1
R2
Across R1
Across R2
Type
efficient
(Ω)
(Ω)
@ 25˚C
(mV)
(µV/˚C)
(mV)
J
52.3
523 1.24k
1k
14.32
T
42.8
432
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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15.60
8
LM185-2.5/LM285-2.5/LM385-2.5
LM385-2.5 Applications
(Continued)
Improving Regulation of Adjstable Regulators
00551907
Schematic Diagram
00551901
9
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LM185-2.5/LM285-2.5/LM385-2.5
Physical Dimensions
inches (millimeters)
unless otherwise noted
Order Number LM185E-2.5/883
NS Package Number E20A
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, or LM285BYH-2.5
NS Package Number H02A
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10
LM185-2.5/LM285-2.5/LM385-2.5
Physical Dimensions
inches (millimeters) unless otherwise noted (Continued)
SOT-23 Package (M3)
Order Number LM385M3-2.5
NS Package Number MA03B
11
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LM185-2.5/LM285-2.5/LM385-2.5
Physical Dimensions
inches (millimeters) unless otherwise noted (Continued)
Small Outline (SO-8) Package (M)
Order Number LM285M-2.5, LM285BXM-2.5, LM285BYM-2.5,
LM385M-2.5, LM385BM-2.5, LM385BXM-2.5 or LM385BYM-2.5
NS Package Number M08A
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12
inches (millimeters) unless otherwise noted (Continued)
TO-92 Plastic Package (Z)
Order Number LM285Z-2.5, LM285BXZ-2.5, LM285BYZ-2.5,
LM385Z-2.5, LM385AXZ-2.5, LM385AYZ-2.5,
LM385BZ-2.5, LM385BXZ-2.5 or LM385BYZ-2.5
NS Package Number Z03A
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.
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LM185-2.5/LM285-2.5/LM385-2.5 Micropower Voltage Reference Diode
Physical Dimensions
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