LM185-1.2QML
Micropower Voltage Reference Diode
General Description
The LM185-1.2 is a micropower 2-terminal band-gap voltage
regulator diodes. Operating over a 10µA to 20mA current
range, it features exceptionally low dynamic impedance and
good temperature stability. On-chip trimming is used to pro-
vide 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 ex-
ceptionally 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.
Features
nOperating current of 10µA to 20mA
n1Ωmaximum dynamic impedance (typical)
nLow temperature coefficient
nLow voltage reference - 1.235V
Ordering Information
NS Part Number JAN Part Number NS Package Number Package Description
LM185E-1.2/883 5962–87594012A E20A 20LD LCC
LM185H-1.2-SMD 5962–8759401XA H02A 2 LD T0–46
LM185H-1.2-QV 5962–8759401VXA H02A 2 LD T0–46
LM185WG-1.2/883 5962–8759401YA WG10A 10LD Ceramic SOIC
LM185BYH-1.2-SMD 5962–8759405XA H02A 2 LD T0–46
LM185WG-1.2-QV 5962–8759401VYA WG10A 10LD Ceramic SOIC
Connection Diagrams
Hermetic Leadless Chip Carrier (E)
TO-46
Metal Can Package (H)
20156135
See NS Package Number E20A
20156106
Bottom View
See NS Package Number H02A
October 2005
LM185-1.2QML Micropower Voltage Reference Diode
© 2005 National Semiconductor Corporation DS201561 www.national.com
Connection Diagrams (Continued)
Ceramic SOIC (WG)
20156134
See NS Package Number WG10A
Schematic Diagram
20156107
LM185-1.2QML
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Absolute Maximum Ratings (Note 1)
Reverse Current 30mA
Forward Current 10mA
Operating Temperature Range −55˚C ≤T
A
≤+125˚C
Maximum Junction Temperature (T
Jmax
) (Note 2) +150˚C
Storage Temperature −55˚C ≤T
A
≤+150˚C
Lead Temperature (Soldering 10 Seconds)
Ceramic SOIC 260˚C
TO-46 package 300˚C
20LD LCC package 300˚C
Thermal Resistance
θ
JA
Metal Can (Still Air) 300˚C/W
Metal Can (500LF / Min Air Flow) 139˚C/W
20LD LCC (Still Air) 100˚C/W
20LD LCC (500LF / Min Air Flow) 73˚C/W
Ceramic SOIC (Still Air) 194˚C/W
Ceramic SOIC (500LF / Min Air Flow) 128˚C/W
θ
JC
Metal Can 57˚C/W
20LD LCC 25˚C/W
Ceramic SOIC 23˚C/W
Package Weight (Typical)
Metal Can TBD
20LD LCC TBD
Ceramic SOIC 210mg
ESD Tolerance (Note 3) 4KV
Quality Conformance Inspection
Mil-Std-883, Method 5005 - Group A
Subgroup Description Temp ˚C
1 Static tests at 25
2 Static tests at 125
3 Static tests at -55
4 Dynamic tests at 25
5 Dynamic tests at 125
6 Dynamic tests at -55
7 Functional tests at 25
8A Functional tests at 125
8B Functional tests at -55
9 Switching tests at 25
10 Switching tests at 125
11 Switching tests at -55
12 Settling time at 25
13 Settling time at 125
14 Settling time at -55
LM185-1.2QML
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LM185–1.2 Electrical Characteristics
DC Parameters
Symbol Parameter Conditions Notes Min Max Units Sub-
groups
V
Ref
Reverse Breakdown Voltage I
R
= 10µA 1.223 1.247 V 1
I
R
= 20µA 1.205 1.26 V 2, 3
I
R
= 1mA 1.223 1.247 V 1
1.205 1.26 V 2, 3
I
R
= 20mA 1.223 1.247 V 1
1.205 1.26 V 2, 3
∆V
Ref
/∆I
R
Reverse Breakdown Voltage
Change with Current
10µA ≤I
R
≤1mA -1.0 1.0 mV 1
20µA ≤I
R
≤1mA -1.5 1.5 mV 2, 3
1mA ≤I
R
≤20mA -10.0 10.0 mV 1
-20.0 20.0 mV 2, 3
V
F
Forward Bias Voltage I
F
= 2mA -1.0 -0.4 V 1
DC Drift Parameters
Delta calculations performed on QMLV devices at group B , subgroup 5, unless otherwise specified on the IPI.
Symbol Parameter Conditions Notes Min Max Units Sub-
groups
V
R
Reverse Breakdown Voltage I
R
= 10µA -0.01 0.01 V 1
I
R
= 20mA -0.01 0.01 V 1
LM185BY–1.2 Electrical Characteristics
DC Parameters
Symbol Parameter Conditions Notes Min Max Units Sub-
groups
V
Ref
Reverse Breakdown Voltage I
R
= 10µA 1.223 1.247 V 1
I
R
= 20µA 1.205 1.26 V 2, 3
I
R
= 1mA 1.223 1.247 V 1
1.205 1.26 V 2, 3
I
R
= 20mA 1.223 1.247 V 1
1.205 1.26 V 2, 3
∆V
Ref
/∆I
R
Reverse Breakdown Voltage
Change with Current
10µA ≤I
R
≤1mA -1.0 1.0 mV 1
20µA ≤I
R
≤1mA -1.5 1.5 mV 2, 3
1mA ≤I
R
≤20mA -10.0 10.0 mV 1
-20.0 20.0 mV 2, 3
V
F
Forward Bias Voltage I
F
= 2mA -1.0 -0.4 V 1
T
C
Temperature Coefficient (Note 4) 50 PPM/˚C 2, 3
Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is
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. Some performance characteristics may degrade when the device is not operated under the listed test
conditions.
Note 2: The maximum power dissipation must be derated at elevated temperatures and is dictated by TJmax (maximum junction temperature), θJA (package junction
to ambient thermal resistance), and TA(ambient temperature). The maximum allowable power dissipation at any temperature is PDmax =(T
Jmax -T
A)/θJA or the
number given in the Absolute Maximum Ratings, whichever is lower.
Note 3: Human body model, 1.5KΩin series with 100pF.
Note 4: The average temperature coefficient is defined as the maximum deviation of reference voltage, at all measured temperatures between the operating TMin
&T
Max, divided by (TMax −T
Min). The measured temperatures (TMeasured) are −55˚C, 25˚C, & 125˚C or ∆VRef /(T
Max −T
Min)
LM185-1.2QML
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Typical Performance Characteristics
Reverse Characteristics Reverse Characteristics
20156113 20156114
Forward Characteristics
Temperature Drift of 3
Representative Units
20156115 20156116
Reverse Dynamic Impedance Reverse Dynamic Impedance
20156117 20156118
LM185-1.2QML
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Typical Performance Characteristics (Continued)
Noise Voltage Filtered Output Noise
20156119 20156120
Response Time
20156121
Typical Applications
Wide Input
Range Reference
20156108
Micropower Reference
from 9V Battery
20156122
Reference from
1.5V Battery
20156123
LM185-1.2QML
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Typical Applications (Continued)
Micropower* 5V Regulator
20156124
*IQ.30µA
Micropower* 10V Reference
20156125
*IQ.20µA standby current
Precision 1µA to 1mA Current Sources
20156126
20156127
LM185-1.2QML
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Typical Applications (Continued)
METER THERMOMETERS
0˚C−100˚C Thermometer
20156128
Calibration
1. Short LM385-1.2, adjust R3 for IOUT= temp at 1µA/˚K
2. Remove short, adjust R2 for correct reading in centigrade
†IQat 1.3V.500µA
IQat 1.6V.2.4mA
Lower Power Thermometer
20156129
*2N3638 or 2N2907 select for inverse HFE .5
†Select for operation at 1.3V
‡IQ.600µA to 900µA
0˚F−50˚F Thermometer
20156130
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
Centigrade Thermometer
20156101
Calibration
1. Adjust R1 so that V1 = temp at 1mV/˚K
2. Adjust V2 to 273.2mV
†IQfor 1.3V to 1.6V battery volt-
age = 50µA to 150µA
Micropower Thermocouple Cold Junction
Compensator
20156131
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
(µV/˚C) @25˚C (mV)
(mV)
J 52.3 5231.24k 15.60 14.32
T 42.8 432 1k 12.77 11.78
K 40.8 412953Ω12.17 11.17
S 6.4 63.4150Ω1.908 1.766
Typical supply current 50µA
LM185-1.2QML
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Revision History Section
Released Revision Section Originator Changes
10/07/05 A New Release, Corporate format L. Lytle 2 MDS data sheets converted into one Corp.
data sheet format. MNLM185-1.2-X Rev 2A3
and MNLM185BY-1.2-X Rev 0B0 data
sheets will be archived.
LM185-1.2QML
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Physical Dimensions inches (millimeters) unless otherwise noted
TO-46 Metal Can Package (H)
NS Package Number H02A
Leadless Chip Carrier Package (E)
NS Package Number E20A
LM185-1.2QML
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Physical Dimensions inches (millimeters) unless otherwise noted (Continued)
Ceramic SOIC Package (WG)
NS Package Number WG10A
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.
For the most current product information visit us at www.national.com.
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LM185-1.2QML Micropower Voltage Reference Diode
