January 2000
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 −55ÊC to 125ÊC temperature range while the LM285-1.2 is rated −40ÊC to 85ÊC and the LM385-1.2 0ÊC to 70ÊC. 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±4 mV (±0.3%) max. initial tolerance (A grade)
nOperating current of 10 µA to 20 mA
n0.6Ω max dynamic impedance (A grade)
nLow temperature coefficient
nLow voltage reference Ð 1.235V
n2.5V device and adjustable device also available
nLM185-2.5 series and LM185 series, respectively
Connection Diagrams
T0-92
Plastic Package (Z)
DS005518-10
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
SOT23
DS005518-33
* 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 MA03B
Diode Reference Voltage Micropower 2.1-2/LM385.1-2/LM285.1-LM185
© 2000 National Semiconductor Corporation |
DS005518 |
www.national.com |
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 |
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) |
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LM185-1.2 |
−55ÊC to +125ÊC |
LM285-1.2 |
−40ÊC to +85ÊC |
LM385-1.2 |
0ÊC to 70ÊC |
Storage Temperature |
−55ÊC to +150ÊC |
Soldering Information |
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TO-92 package: 10 sec. |
260ÊC |
TO-46 package:10 sec. |
300ÊC |
SO and SOT Pkg. |
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Vapor phase (60 sec.) |
215ÊC |
Infrared (15 sec.) |
220ÊC |
See AN-450 ªSurface Mounting Methods and Their Effect on Product Reliabilityº for other methods of soldering surface mount devices.
Electrical Characteristics (Note 4)
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LM185-1.2 |
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LM185BX-1.2 |
LM385B-1.2 |
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LM185BY-1.2 |
LM385BX-1.2 |
LM385-1.2 |
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LM285-1.2 |
LM385BY-1.2 |
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Parameter |
Conditions |
Typ |
LM285BX-1.2 |
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(Limit) |
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LM285BY-1.2 |
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Tested |
Design |
Tested |
Design |
Tested |
Design |
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Limit |
Limit |
Limit |
Limit |
Limit |
Limit |
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(Notes |
(Note 6) |
(Note 5) |
(Note 6) |
(Note 5) |
(Note 6) |
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5, 8) |
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Reverse Breakdown |
TA = 25ÊC, |
1.235 |
1.223 |
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1.223 |
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1.205 |
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V(Min) |
Voltage |
10 µA ≤ IR ≤ 20 mA |
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1.247 |
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1.247 |
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1.260 |
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V(Max) |
Minimum Operating |
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8 |
10 |
20 |
15 |
20 |
15 |
20 |
µA |
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Current |
LM385M3-1.2 |
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10 |
15 |
(Max) |
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Reverse Breakdown |
10 µA ≤ IR ≤ 1 mA |
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1 |
1.5 |
1 |
1.5 |
1 |
1.5 |
mV |
Voltage Change |
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(Max) |
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with Current |
1 mA ≤ IR ≤ 20 mA |
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10 |
20 |
20 |
25 |
20 |
25 |
mV |
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(Max) |
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Reverse Dynamic |
IR = 100 µA, f = 20 Hz |
1 |
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Ω |
Impedance |
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Wideband Noise |
IR = 100 µA, |
60 |
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µV |
(rms) |
10 Hz ≤ f ≤ 10 kHz |
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Long Term Stability |
IR = 100 µA, T = 1000 Hr, |
20 |
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ppm |
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TA = 25ÊC ±0.1ÊC |
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Average Temperature |
IR = 100 µA |
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Coefficient (Note 7) |
X Suffix |
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30 |
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30 |
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ppm/ÊC |
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Y Suffix |
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50 |
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50 |
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ppm/ÊC |
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All Others |
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150 |
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150 |
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150 |
ppm/ÊC |
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(Max) |
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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 150ÊC
LM285 125ÊC
LM385 100ÊC
Thermal Resistance |
TO-92 |
TO-46 |
SO-8 |
SOT23 |
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θJA (junction to ambient) |
180ÊC/W (0.4" leads) |
440ÊC/W |
165ÊC/W |
283ÊC/W |
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170ÊC/W (0.125" leads) |
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θJC (junction to case) |
N/A |
80ÊC/W |
N/A |
N/A |
Note 4: Parameters identified with boldface type apply at temperature extremes. All other numbers apply at TA = TJ = 25ÊC.
2.1-2/LM385.1-2/LM285.1-LM185
3 |
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