LM185BXH-2.5/883 - National Semiconductor

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 µAto 20 mAcurrent range, they feature exception-

ally 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 transis-

tors and resistors, low noise and good long term stability re-

sult.

Careful design of the LM185-2.5 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 LM185-2.5 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. Fur-

ther, the wide operating current allows it to replace older ref-

erences with a tighter tolerance part. For applications requir-

ing 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 car-

rier package.

Features

n±20 mV (±0.8%) max. initial tolerance (A grade)

nOperating current of 20 µA to 20 mA

n0.6Ωdynamic impedance (A grade)

nLow temperature coefficient

nLow voltage reference—2.5V

n1.2V device and adjustable device also

available—LM185-1.2 series and LM185 series,

respectively

Connection Diagrams

TO-92

Plastic Package

DS005519-8

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

SO Package

DS005519-11

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

DS005519-29

*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

December 1999

LM185-2.5/LM285-2.5/LM385-2.5 Micropower Voltage Reference Diode

Connection Diagrams (Continued)

LCC

Leadless Chip Carrier

DS005519-14

Order Number LM185E-2.5/883

See NS Package Number E20A

TO-46

Metal Can Package

DS005519-13

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

LM185-2.5/LM285-2.5/LM385-2.5

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Absolute Maximum Ratings (Notes 1, 2)

If Military/Aerospace specified devices are required,

please contact the National Semiconductor Sales Office/

Distributors for availability and specifications.

Reverse Current 30 mA

Forward Current 10 mA

Operating Temperature Range (Note 3)

LM185-2.5 −55˚C to + 125˚C

LM285-2.5 −40˚C to + 85˚C

LM385-2.5 0˚C to 70˚C

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 Package

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)

Parameter Conditions Typ

LM385A-2.5

Units

(Limits)

LM385AX-2.5

LM385AY-2.5

Tested Design

Limit Limit

(Note 5) (Note 6)

Reverse Breakdown I

=100 µA 2.500 2.480 V(Min)

Voltage 2.520 V(Max)

2.500 2.470 V(Min)

2.530 V(Max)

Minimum Operating 12 18 20 µA

Current (Max)

Reverse Breakdown I

MIN

≤I

≤1mA 1 1.5 mV

Voltage Change with (Max)

Current 1 mA ≤I

≤20 mA 10 20 mV

(Max)

Reverse Dynamic I

=100 µA, 0.2 0.6 Ω

Impedance f =20 Hz 1.5

Wideband Noise (rms) I

=100 µA 120 µV

10 Hz ≤f≤10 kHz

Long Term Stability I

=100 µA,

T=1000 Hr, 20 ppm

=25˚C ±0.1˚C

Average Temperature I

MIN

≤I

≤20 mA

Coefficient (Note 7) X Suffix 30 ppm/˚C

Y Suffix 50 (Max)

All Others 150

LM185-2.5/LM285-2.5/LM385-2.5

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Electrical Characteristics (Continued)

LM185-2.5

LM185BX-2.5 LM385B-2.5

LM185BY-2.5 LM385BX-2.5 LM385-2.5 Units

LM285-2.5 LM385BY-2.5 (Limit)

Parameter Conditions Typ LM285BX-2.5

LM285BY-2.5

Tested 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)

Reverse Breakdown T

=25˚C, 2.5 2.462 2.462 2.425 V(Min)

Voltage 20 µA ≤I

≤20 mA 2.538 2.538 2.575 V(Max)

Minimum Operating

Current 13 20 30 20 30 20 30 µA

(Max)

LM385M3-2.5 15 20

Reverse Breakdown

Voltage Change with

Current

20 µA ≤I

≤1mA 1 1.5 2.0 2.5 2.0 2.5 mV

(Max)

1mA≤I

≤20 mA 10 20 20 25 20 25 mV

(Max)

Reverse Dynamic I

=100 µA, 1 Ω

Impedance f =20 Hz

Wideband Noise (rms) I

=100 µA, 120 µV

10 Hz ≤f≤10 kHz

Long Term Stability I

=100 µA,

T=1000 Hr, 20 ppm

=25˚C ±0.1˚C

Average Temperature I

=100 µA

Coefficient (Note 7) X Suffix 30 30 ppm/˚C

Y Suffix 50 50 ppm/˚C

All Others 150 150 150 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 in-

tended 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 TO-92 TO-46 SO-8 SOT-23

θja (Junction to Ambient) 180˚C/W (0.4" Leads) 440˚C/W 165˚C/W 283˚C/W

170˚C/W (0.125" Leads)

θjc (Junction to Case) N/A 80˚C/W N/A 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 available on request.

LM185-2.5/LM285-2.5/LM385-2.5

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Typical Performance Characteristics

Applications

LM385-2.5 Applications

Reverse Characteristics

DS005519-15

Reverse Characteristics

DS005519-16

Forward Characteristics

DS005519-17

Temperature Drift

DS005519-18

Reverse Dynamic

Impedance

DS005519-19

Reverse Dynamic

Impedance

DS005519-20

Noise Voltage

DS005519-21

Filtered Output Noise

DS005519-22

Response Time

DS005519-23

Wide Input Range Reference

DS005519-12

Micropower Reference from 9V Battery

DS005519-2

LM185-2.5/LM285-2.5/LM385-2.5

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LM385-2.5 Applications (Continued)

Micropower 5V Reference (Note 9)

DS005519-9

Note 9: IQ≅40 µA

Micropower 10V Reference (Note 10)

DS005519-10

Note 10: IQ≅30 µA standby current

LM185-2.5/LM285-2.5/LM385-2.5

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LM385-2.5 Applications (Continued)

Precision 1 µA to 1 mA Current Sources

DS005519-24

DS005519-25

METER THERMOMETERS

0˚C–100˚C Thermomemter

DS005519-26

Calibration

1. Short LM385-2.5, adjust R3 for I

OUT

=temp at 1µA/˚K

2. Remove short, adjust R2 for correct reading in centi-

grade

0˚F–50˚F Thermomemter

DS005519-27

Calibration

1. Short LM385-2.5, adjust R3 for I

OUT

=temp at 1.8 µA/˚K

2. Remove short, adjust R2 for correct reading in ˚F

LM185-2.5/LM285-2.5/LM385-2.5

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LM385-2.5 Applications (Continued)

Seebeck Voltage Voltage

Thermocouple Co- R1 R2 Across R1 Across R2

Type efficient (Ω)(Ω)@

25˚C (mV)

(

V/˚C) (mV)

J 52.3 523 1.24k 15.60 14.32

T 42.8 432 1k 12.77 11.78

K 40.8 412 953Ω12.17 11.17

S 6.4 63.4 150Ω1.908 1.766

Typical supply current 50 µA

Micropower Thermocouple Cold Junction

Compensator

DS005519-6

Adjustment Procedure

1. Adjust TCADJ 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.

Improving Regulation of Adjstable Regulators

DS005519-7

LM185-2.5/LM285-2.5/LM385-2.5

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Schematic Diagram

DS005519-1

LM185-2.5/LM285-2.5/LM385-2.5

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Physical Dimensions inches (millimeters) unless otherwise noted

Order Number LM185E-2.5/883

NS Package Number E20A

LM185-2.5/LM285-2.5/LM385-2.5

www.national.com 10

Physical Dimensions inches (millimeters) unless otherwise noted (Continued)

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

LM185-2.5/LM285-2.5/LM385-2.5

www.national.com11

Physical Dimensions inches (millimeters) unless otherwise noted (Continued)

SOT-23 Package (M3)

Order Number LM385M3-2.5

NS Package Number MA03B

LM185-2.5/LM285-2.5/LM385-2.5

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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

LM185-2.5/LM285-2.5/LM385-2.5

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Physical Dimensions inches (millimeters) unless otherwise noted (Continued)

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DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL

COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein:

1. Life support devices or systems are devices or

systems which, (a) are intended for surgical implant

into the body, or (b) support or sustain life, and

whose failure to perform when properly used in

accordance with instructions for use provided in the

labeling, can be reasonably expected to result in a

significant injury to the user.

2. A critical component is any component of a life

support device or system whose failure to perform

can be reasonably expected to cause the failure of

the life support device or system, or to affect its

safety or effectiveness.

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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

LM185-2.5/LM285-2.5/LM385-2.5 Micropower Voltage Reference Diode

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.